PubMed Help
Updated: July 18, 2001

PubMed Searching

PubMed was developed by the National Center for Biotechnology Information (NCBI) at the National Library of Medicine (NLM), the Overview contains additional information.

Databases on the black menu bar are links to PubMed and the other NCBI resources.

PubMed searching is easy, just enter search terms in the query box, and press the Enter Go or click Go.  The Features bar directly beneath the query box provides access to additional search options. The PubMed query box and Features bar are available from every screen, so don't need to return to the homepage to enter a new search.

You may enter one or more terms (e.g., vitamin c common cold) in the query box and PubMed automatically combines (ANDs) significant terms together using automatic term mapping. The terms are searched in various fields of the citation. If you search includes Boolean operators AND, OR, NOT, they must be in upper case, e.g., vitamin c OR zinc.

Once you click Go, PubMed will display your search results.  The query box displays your search terms as you entered them.

You can modify your current search by adding or eliminating terms in the query box or in Details.  If you applied Limits, the check box next to Limits will be marked and a listing of your limit selections will be displayed.  To turn off the existing limits, click on the check box to remove the check before running your next search.

Author Names
To search by an author's name enter the name in the format of last name plus initials (no punctuation), e.g., smith ja, jones k.  PubMed automatically truncates the author's name to account for varying initials and designations such as Jr. or 2nd.  A name entered using this format will search in the author field.   If only the author's last name is entered, PubMed searches the name in All Fields, except when the author name is found in the MeSH (National Library of Medicine's Medical Subject Headings) Translation table (e.g., Yang will search as Yin-Yang [MeSH] or Yang [Text Word].) To search for an author in the author field when only the last name is available qualify the author name with the author search field tag [au], e.g., yang [au].

Note:

Use double quotes around the author's name with the author search field tag [au] to turn off the automatic truncation, e.g., "smith j" [au].
Journal Titles
You may search by the full journal title, e.g., molecular biology of the cell; the MEDLINE abbreviation, e.g., mol biol cell; or the ISSN number (standardized international code), e.g., 1059-1524. See the Journal Browser  for the full journal titles.

Note:

  1. If a journal name is also a MeSH term (e.g., Gene Therapy, Science, or Cell), PubMed will search the unqualified term as MeSH. Qualify the journal title with the Journal Title search field tag, e.g., gene therapy [ta], to search for the journal name.
  2. Qualify single word journal titles using the Journal Title search field tag, e.g., scanning [ta], as PubMed will search unqualified single journal titles in All Fields.
  3. Searching with the full journal title or MEDLINE abbreviation is recommended for complete retrieval of indexed items; the ISSN number is not guaranteed to be on older citations.
  4. If a journal name includes parentheses or brackets, enter the name without the parentheses or brackets, e.g., enter J Hand Surg [Am] as J Hand Surg Am.
See also: Automatic Term Mapping
Unqualified terms that are entered in the query box are matched (in this order) against a MeSH (Medical Subject Headings) Translation Table, a Journals Translation Table, a Phrase List, and an Author Index.  PubMed ignores stopwords from search queries.

1. MeSH Translation Table
The MeSH translation table contains MeSH Terms, the See-Reference mappings (also known as entry terms) for MeSH Heading terms, Subheadings, terms derived from the Unified Medical Language System (UMLS) that have equivalent synonyms or lexical variants in English, and the Supplementary Concept (Substance) Names, and their synonyms. If a match is found in this translation table, the term will be searched as MeSH and as a Text Word. For example, if you enter vitamin h in the query box, PubMed will translate this search to: ("Biotin"[MeSH Terms] OR vitamin h[Text Word]) - vitamin h is an entry term for the MeSH term Biotin.

Note:

Click on Details to verify how your terms are translated. If you want to report a translation that does not seem accurate for your search topic, please e-mail the information to pubmed@ncbi.nlm.nih.gov
2. Journals Translation Table
The Journals translation table contains the full journal title, the MEDLINE abbreviation, and the ISSN number.  These map to the journal abbreviation which is used to search journal names in PubMed.  For example, if you enter the journal title, new england journal of medicine in the PubMed query box, PubMed will translate this search to: "N Engl J Med"[Journal Name].

3. Phrase List
If no match is found in the MeSH or Journals Translation tables, PubMed consults a Phrase List. Phrases on this list are generated from MeSH, the UMLS, and Supplementary Concept Substance Names, e.g., cold compresses.

4. Author Index
If the phrase is not found in the above tables or list, and is a word with one or two letters after it, PubMed then checks the Author index.

If no match is found?
PubMed breaks apart the phrase and repeats the above automatic term mapping process until a match is found. If there is no match, the individual terms will be combined (ANDed) together and searched in All Fields.

See Also:

Truncation (finding all terms that begin with a given text string)
Place an asterisk at the end of a term to search for all terms that begin with that word; for instance flavor* will find all terms that begin with the letters flavor, e.g., flavored, flavorful, flavoring, etc. PubMed searches for the first 150 variations of a truncated term. If a truncated term, e.g., staph*, produces more than 150 variations, PubMed displays the warning message shown below.

Wildcard search for 'term*' used only the first 150 variations. Lengthen the root word to search for all endings.

Note:

  1. Phrases that include a space in a word after the asterisk will NOT be included; for example, infection* includes infections, but not infection control.
  2. Truncation turns off automatic term mapping and the automatic explosion of a MeSH term. For example, heart attack* will not map to the MeSH term, Myocardial Infarction or include any of the more specific terms, e.g., Myocardial Stunning; Shock, Cardiogenic.
Phrase Searching (specifying a phrase in a search)
PubMed does not actually perform adjacency searching, but uses a list of recognized phrases against which search terms are matched. Many phrases are recognized by PubMed's automatic term mapping feature. For example, if you enter poison ivy, PubMed recognizes these two words as a phrase and searches it as one search term. If your phrase is not recognized, you can instruct PubMed to check for a phrase in the Index of searchable terms. This is done by entering quotes (" ") around the phrase, e.g., "single cell."

Note:

  1. If your search phrase is not on the list of recognized phrases, then the double quotes are ignored and the phrase is processed using automatic term mapping.  Your phrase may actually appear in the citation and abstract data, yet not be on the phrase list.
  2. When you enclose a phrase in double quotes, PubMed will not perform automatic term mapping. For example, "health planning" will include citations that are indexed to the MeSH term, Health Planning, but will not include the more specific terms, e.g., Health Care Rationing, Health Care Reform, Health Plan Implementation and so on, that are typically included with the automatic MeSH mapping.
For Additional Information on Search Strategies, see also: Additional Search Commands

Search Rules and Syntax

  1. Boolean operators, AND, OR, NOT must be entered in upper case, e.g., vitamin c OR zinc.
  2. PubMed processes all Boolean connectors in a left-to-right sequence. You can change the order that PubMed processes a search statement by enclosing individual concepts in parentheses. The terms inside the set of parentheses will be processed as a unit and then incorporated into the overall strategy, e.g., common cold AND (vitamin c OR zinc).
  3. If PubMed finds a phrase within a search strategy string that uses unqualified terms it will automatically search the terms as a phrase rather than simply combining the individual words.   For example, if you enter air bladder fistula in the PubMed query box, PubMed will search "air bladder" as a phrase. If you do not want this automatic phrase parsing enter each term separated by the Boolean operator AND, e.g., air AND bladder AND fistula. Click Details to see how PubMed translated your search strategy.
  4. Follow PubMed's search and syntax rules to enter search terms, specify the search field to be searched, and the Boolean operators in your search statement:
      search term [tag] BOOLEAN OPERATOR search term [tag]

Examples of Boolean Search Statements:

      Find citations on DNA that were authored by Dr. Crick in 1993.

            dna [mh] AND crick [au] AND 1993 [dp]

      Find articles that deal with the effects of heat or humidity on multiple sclerosis, where
      these words appear in all fields in the citation.

            (heat OR humidity) AND multiple sclerosis

      Find English language review articles that discuss the treatment of asthma in preschool children.

            asthma/therapy [mh] AND review [pt] AND child, preschool [mh] AND
               english [la]

Search Field Qualification
Terms can be qualified using PubMed's Search Field tags.

  1. Add the search tag after the term, e.g., aromatherapy [mh].
  2. Search field tags must be enclosed in square brackets,  [mh].
  3. Case does not matter nor does spacing, e.g., crabs [mh] = Crabs[mh].
Dates & Date Ranging
Dates or date ranges must be entered using the format YYYY/MM/DD [date field], e.g., 1997/10/06 [edat] or 1998/03/15 [dp]. The month and day are optional, e.g., 1997 [edat] or 1997/03 [dp].

To enter a date range, insert a colon (:) between each date, e.g., 1993:1995 [edat] or
1997/01:1997/06 [edat].

PubMed's Date Fields:

Date of Publication [DP]
Entrez Date [EDAT]  The date the citation first entered PubMed.
MeSH Date [MHDA]  The date the citation was indexed with MeSH terms.

Date ranging is also available from the fill-in-the-blank selection on the Limits screen.

Subsets
There are three types of PubMed subsets: Journal, Subject, and Citation Status. PubMed's Limit screen has a Subset pull-down menu where some of these subsets can be selected; alternatively the subset can be incorporated into a search by entering a subset value.

Journal subsets and their values are listed below. Several are closed subsets no longer being assigned to current data.

AIM - Abridged Index Medicus A list of indexed core clinical journals created 20 years ago
IM - Indexed Index Medicus journals
D  - Indexed dentistry journals
N  - Indexed nursing journals
X - Indexed AIDS/HIV journals, non-Index Medicus
B - Indexed biotechnology journals (assigned 1990 - 1998), non-Index Medicus
K - Indexed consumer health journals, non-Index Medicus
H - Indexed health administration journals, non-Index Medicus
R - Indexed reproduction journals (assigned 1972 - 1979), non-Index Medicus
C - Indexed communication disorders journals (assigned 1977 - 1997), non-Index Medicus
T - Indexed health technology assessment journals, non-Index Medicus

To search for a journal subset use jsubset? where ? stands for the journal subset value.

 For example: neoplasms AND jsubsetaim

Note:

  1. The Journal subset does not use a search field tag.
  2. Search LOCATORplus, NLM's catalog of books, audiovisuals, and journals for subset journal titles.
Subject subsets are AIDS, Toxicology (tox), and Complementary Medicine (cam).  Subject subsets may be selected from the Subset pull-down menu in Limits, or searched as aids, tox, or cam - using the [SB] search tag.

For example: asthma AND cam [sb]

Citation Status subsets, MEDLINE, in process, and supplied by publisher, can be selected from the Subset pull-down menu in Limits, or searched directly with the [SB] search tag as medline, in process, or publisher.

The following Citation Status tags display next to the PMID on all PubMed citations:

PubMed Central - To limit to citations with full-text links to PubMed Central use the following strategy with the [SB] search tag:  medline pmc [sb]

Citations with Abstracts

To search for citations with abstracts use the value 'hasabstract'.

For example: neoplasms AND hasabstract

Note:

The 'hasabstract' value does not use a search field tag.
Limiting to only items with abstracts is also available form the Limits screen.

Ahead of Print Citations
To search for ahead of print citations enter the value 'pubstatusaheadofprint'.

For example: pubstatusaheadofprint AND gene

These citations display the tag [epub ahead of print] immediately following the date of the citation.

Details
Details lets you view your search strategy as it was translated using PubMed's automatic term mapping and search rules and syntax. From Details, you can save a search strategy or edit the search strategy and resubmit it. The Details window also contains error messages and notes.

Editing Your Search in Details
The PubMed Query box shows the actual search strategy and syntax used to run the search. Beneath this box, the Result number hyperlink displays the total number of matches for the current search. To  return to the current search results screen, click this link or use the "Back" function of your Web browser. The Translations area details how each term was translated using PubMed's search rules and syntax, and the User Query area shows the search terms as you entered them in the query box.

To edit the search strategy in the PubMed Query box,  click in the box to add or delete terms and then click Search.

Saving a Search Strategy from Details
From the Details window, use the URL button to display the current search strategy as a URL and then bookmark the URL for future use.

To save a search strategy:

  1. From the Details window, click on URL.  PubMed will return to the search results screen. The translated search strategy will be displayed in the query box and this search strategy will also be embedded as part of the URL
  2. Next, use your Web browser's bookmark function to save the URL as a bookmark.  After saving the bookmark, you may want to use your Web browser's edit functions to rename the bookmark.
  3. You may also save your search strategies using the Cubby.
Note:
Searches that were created using a search statement number in History  (e.g., (#1 or #2 AND human[mh]]) should not be saved using the URL feature as the search statements represented by these numbers are lost when History is deleted.
Cookies

What is a "cookie?"
A "cookie" is information sent by a web site server (e.g., PubMed) to your computer. In the case of PubMed, it is information about your interactions that may be needed later to perform a function. Cookies allow PubMed to provide more interactive features such as Preview/Index, Clipboard, History, and the Cubby. Cookies placed by PubMed are removed from your computer after a set time period.

If you are interested, there are many web sites that provide information about cookies.  Try surfing for "What are cookies?" Netscape provides technical information.

How can I tell if my system accepts cookies?
Cookie-dependent features of PubMed include Preview/Index, History, Clipboard, and the Cubby. To use these features, your system must be able to accept cookies. Below we provide information on how to verify that your system is set to enable cookies. If you still have problems using cookie-dependent features of PubMed even after enabling cookies possible reasons may include:

1) Cookies are blocked by your provider or institution.

Please check with your Internet provider and/or the system administrator at your institution to see if cookies can be accepted. Even if you have them enabled in your web browser, if they are blocked by your provider or institution (e.g., by a firewall, proxy server, etc.), cookie-dependent features of PubMed won't work.

2) Your computer's date & time settings are incorrect.

Please check your computer's time settings to ensure that they are correct. For IBM-compatible PCs, open Start, Settings, Control Panel ... Double-click the Date/Time icon. On the Date & Time tab, set the correct date & time for your location. On the Time Zone tab, set the correct time zone for your location. Click OK.

For Macs, use the Apple pull-down menu to select Control Panels, Date &Time... Set the correct date & time as well as the correct time zone. Close the Date & Time control panel.

      Enabling Cookies:
In Microsoft Internet Explorer 5, pull down from the Tools menu  and select Internet  Options...,  click on the Security tab.  If you are set for High Security, you may want to select a lower setting that will permit your browser to accept cookies.  (MSIE 4 users: Pull down from View; select Internet Options...;  Cookie settings are under the Advance tab.) Check IE's Help for more information.

In Netscape 4.6 pull down the Edit menu and select Preferences...,  click on Advanced.  Look in the "Cookies" section.  If this is set for "Disable Cookies," you may want to change this to another selection that will permit your browser to accept cookies.  Check Netscape's Help for more information.

If you are using another brand of web browser or an Internet provider, please check the Help for that browser, or contact your support provider.

Features Bar

Limits
Click Limits from the Features bar to limit your search to specific age group, gender, or human or animal studies.   Limits also allows you to restrict to articles published in a specific language, and to specific types of articles such as review articles.  You can limit by either Entrez or Publication Date. And lastly, you may limit your retrieval to a specific subset of citations within PubMed, such as AIDS-related citations or nursing journals.

Note:

If you select a limit and either run a search or move to another screen, a check will appear in a box next to Limits on the Features bar to indicate that limits have been selected.  If you then run a search, the limits in effect will appear in the yellow bar above the Display button.  To turn off the limits before you run your next search, click on the box to remove the check.
 


Field Selection
You may limit your search terms to a specific search field. All Fields is the default for searching. To select a specific field, click the All Fields pull-down menu and select a search field.

See also:

Only Items with Abstracts
You may limit your retrieval to only citations that contain an abstract by using the check box next to  only items with abstracts.  Citations to articles published prior to 1975 do not include abstracts.

Publication Types
All citations in PubMed are for journal articles. However, you may limit your retrieval based on the type of material the article represents (e.g., Clinical Trials or Review articles). The Publication Types pull-down menu contains a list of frequently searched publication types.  If you do not make a selection, PubMed will not restrict to any particular publication type.  The available selections are:

Note:
If you use the Publication Types pull-down menu to select a search field, your retrieval will be limited to MEDLINE citations. The in process and supplied by publisher citations will be excluded as they have not yet completed the indexing process and will not include a Publication Type.
See also: PubMed indexes journals published in approximately forty languages.  The Languages pull-down menu contains a list of frequently searched languages. If you do not select a language, PubMed will not limit your retrieval by language.

Languages
To select a language, click on the Languages pull-down menu and select one of the following languages:

Ages
To select a specific age group for human studies, click on the Ages pull-down menu and select from one of the age groups listed below.  If you do not make a selection, PubMed will not limit your retrieval by age groups. Note:
If you use the Ages pull-down menu to select a search field, your retrieval will be limited to MEDLINE citations. The in process and supplied by publisher citations are automatically excluded as they have not yet completed the indexing process and do not carry these  data.
Gender
To select a specific gender for a human study, click on the Gender pull-down menu and select either Female or Male.  If you do not make a selection, PubMed will not limit your retrieval by gender.

Note:

If you use the Gender pull-down menu to select a search field, your retrieval will be limited to MEDLINE citations. The in process and supplied by publisher citations are automatically excluded as they have not yet completed the indexing process and do not carry these data.
Human or Animal
To select a specific study group, click on the Human or Animal pull-down menu and select either, Human or Animal.  If you do not make a selection, PubMed will not limit your retrieval by Human and Animal studies.

Note:

If you use the Human or Animal pull-down menu to select a search field, your retrieval will be limited to MEDLINE citations. The in process and supplied by publisher citations are automatically excluded as they have not yet completed the indexing process and do not carry these data.
Subsets
The Subsets pull-down menu allows you to limit your retrieval to one of the following subsets contained within PubMed: To limit your retrieval to one of these subsets, click on the Subsets pull-down menu and select from the following options: Dates
PubMed contains citations published back to 1966 and new citations are added daily. The Entrez Date is the date the citation was added to PubMed.  The Publication Date is the date the article was published.

When PubMed displays your search results, the citations are displayed in descending Entrez Date order i.e., last in, first out. If you do not specify a date range, PubMed searches for citations to articles back to 1966.

Preview/Index
Use the Preview/Index feature to: To preview the number of results before displaying the citations, type your term(s) in the query box and click Preview.  Preview displays the number of citations in your search results.  To refine your search strategy, add another term to the existing term(s) in the query box and click Preview.  The additional terms will be combined with the existing terms, and the new search with the new number of citations will display.  Continue adding terms until your strategy is complete. To display your results, click on the result number (hypertext) in the Preview display.

To search for terms from specific search fields use the Add Term(s) to Query text box.    Select a search field from the All Fields pull-down menu and enter a term in the text box.  Click AND, OR, or NOT to add the term to the query box with the appropriate search field tag, or click Preview to see the number of results..

The available Boolean operators are:

     Intersection (AND) - only those citations that contain selected terms.
     Union (OR) - citations that contain at least one of the selected terms.
     Difference (NOT) - exclude citations with the selected term.

You can also use Index to select from a list of terms within a search field.  Select a search field from the All Fields pull-down menu, enter a term in the box, and click Index. PubMed displays an alphabetic list of terms in the Index for the selected search field.  The number of citations in PubMed that contain the term appears in parentheses to the right of the term. You can scroll up or down the list, or click Up or Down to move along in the Index.

Highlight a term by clicking on it.  Then click the appropriate operator, AND, OR, NOT. The selected term will be added to the query box.  To OR together multiple terms from an Index display and then add (or AND) them to your search, click on each term while holding down the Ctrl-key (PC) or the Command-key (Mac).  When all the terms you want are highlighted, click the connector AND to add the terms (ORed together) to the query.

You may then continue to add additional terms from other search fields. Once your strategy is complete, click Preview to see the number of results, or click Go to display the citations.

For example, to see the MeSH Terms beginning with "chickenpox," select MeSH Terms from the All Fields pull-down menu, enter the term, chickenpox, in the text box, and click Index.  Scroll down in the Index box, highlight the MeSH Term "chickenpox vaccine," and click AND.  "Chickenpox vaccine" [MeSH Terms] will be added to the query box.

Note:
  1. Preview/Index displays the last three queries from History.  Use History to review up to the last 100 queries.
  2. PubMed automatically truncates on the author's name to account for varying initials, e.g., smith j will retrieve smith ja, smith jb, smith j jr, etc.  When an author's name is displayed with the @ symbol after the first initial, it reflects the authors in PubMed without a middle initial e.g., smith j@ will only retrieve smith j.
  3. PubMed processes all Boolean operators left to right. To change this order enclose search terms to be processed first in parentheses, e.g., common cold AND (vitamin c OR zinc).  You may edit (e.g., add parentheses) in any query box.  PubMed will automatically OR (and add parentheses) for multiple terms selected from the Index.
  4. Preview uses cookies to keep a history of your searches.  In order for you to use this feature your web browser must be set to accept cookies.
History
PubMed holds all your search strategies and results in History.  You can see your search History by clicking on History from the Features bar.  History is only available after you run your first search.  History lists and numbers your searches in the order in which they were run.  History displays the search number, your search query, the time of search, and the number of citations in your results.  To view the results from a search, click on the number of results.

You can combine searches or add additional terms to an existing search by using the pound sign (#) before the search number, e.g., #2 AND #6, or  #3 AND (drug therapy OR diet therapy).  Once you have entered a revised search strategy in the query box, click Go to view the search results.  Click Clear History to remove all searches from the History screen and the Preview/Index screen.

Note:

  1. The maximum number of queries held in History is 100.  Once the maximum number is reached, PubMed will remove the oldest search from the History to add the most current search.
  2. The Search History will be lost after one hour of inactivity on PubMed or any of the other Entrez databases. The Clear History button in History will also clear the Preview/Index history information.
  3. PubMed will move a search statement number to the top of the History if the new search is the same as a previous search.
  4. A separate Search History will be kept for each of the Entrez databases although the search statement numbers will be assigned sequentially for all databases.
  5. PubMed uses cookies to keep a history of your searches.  In order for you to use this feature your web browser must be set to accept cookies.
  6. Citations in the Clipboard are represented by the search number #0 which may be used in Boolean search statements. For example, to limit the citations you have collected in the Clipboard to English language citations use the following search: #0 AND english [la].  This does not change or replace the Clipboard contents.
  7. History search numbers may not be continuous because some numbers are assigned to intermediate processes such as displaying a citation in another format.


Clipboard
The Clipboard gives you a place to collect selected citations from one search or several searches. After you add citations to the Clipboard you may then want to use the print, save, or order buttons. The maximum number of items that can be placed in the Clipboard is 500. Once you have added items to the Clipboard, you can click on Clipboard from the Features bar to view your selections.

Add to Clipboard
To place an item in the Clipboard, click on the check box to the left of the citation and then click Add to Clipboard.  Once you have added a citation to the Clipboard, the record number color will change to green.

Note:

  1. If you click Add to Clipboard without selecting citations using the check box, PubMed will add all (up to 500 citations) of your search results to the Clipboard.
  2. The Clipboard will be lost after one hour of inactivity on PubMed or any of the other Entrez databases.
  3. PubMed uses cookies to add your selections to the Clipboard.  In order for you to use this feature your web browser must be set to accept cookies.
  4. Citations in the Clipboard are represented by the search number #0 which may be used in Boolean search statements. For example, to limit the citations you have collected in the Clipboard to English language citations use the following search: #0 AND english [la].  This does not affect or replace the Clipboard contents.

Saving from the Clipboard
Citations are initially displayed in the summary format in the order they were added.  Use Sort to change the order. You can select all or individual citations to display or save in one of the citation display formats. Select the desired format from the pull-down menu, click Save to save your selections to a file, or use the Print feature of your web browser to print the citations.  Printing from your web browser will only print the information and citations listed on the web page. You may also display citations as plain text without the sidebar menu and toolbars by clicking the Text button.

Note:

Your results may be on more than one page.  PubMed will retain your selections from all pages of your results.  To mark specific citations to save, click on the check box to the left of each citation and continue to page through your results.   Use Save to save all the selected citations to a file.
See Also: Ordering Documents in the Clipboard
Order allows you to order the full-text copy of an article from a library in your area using the Order Documents feature of PubMed.

Note:

  1. Prior to using this program you must establish an agreement with a Loansome Doc participating library. Local fees may apply. For information on the medical libraries in your area (or country) that can provide the Loansome Doc service, click on Order Documents from the PubMed sidebar menu, then "Registration" from the Loansome Doc Ordering System screen.
  2. You may use the Clipboard to collect items from multiple searches before ordering.
Once you have registered with Loansome Doc, you can order citations, by clicking on the check box to the left of each citation in the Clipboard.  When you have finished marking your selections (you may move to other pages within the Clipboard) click Order.  Citations will remain in the Clipboard after the order process.

Sort
Click Add to Clipboard for citations you want to sort by author, journal or publication date. Click Clipboard, then select a sort field from the Sort pull-down menu and click Display.   Publication Date sorts the most recent citations first, the secondary sort is journal.  Author and journal sorts A to Z, the secondary sort is publication date.

Deleting Citations from the Clipboard
You can delete citations from your Clipboard.  To mark citations for deletion, click on the check box to the left of the citation and click Remove from Clipboard.  To empty your entire Clipboard, do not mark any of the citations, simply click Remove from Clipboard.

Cubby

The Cubby stores search strategies, that may be updated at any time, and LinkOut preferences to specify which LinkOut providers you want displayed in PubMed, and changes the default document delivery service.  In order for you to use this feature your web browser must be set to accept cookies.

Registering for the Cubby
Click Cubby from the PubMed sidebar. Then click "I Want to Register for Cubby."

Provide (make up) the following information, then click Register:

Logging In
You must login to access the Cubby. This login will remain active for 12 hours. If you've already registered, type your User Name and Password and click Login.

Forgot Your Password?
If you've forgotten your password, click "Help! I Forgot My Password." In the Password Forgotten box, enter your User Name and click on Lookup. Enter either your Mother's maiden name or your Pet's name on the next screen. Once this has been verified, the Cubby will assign you a new Password. Make a note of this as you will need it to Login to the Cubby, and if you want to change your password to something you can easily remember.

Changing Your Password
Select Change Password from the Cubby Resources menu sidebar and enter your old password and new password, then click Change.

Log Out
Click Log Out from the Cubby sidebar to Log Out. Your Login will remain active for 12 hours, unless you Log Out.

Cubby Stored Searches
Click on Cubby on the sidebar to store a search strategy, see a list of your stored searches, update, or delete a stored search.

How to Store a Cubby Stored Search

  1. Run or Preview your search. You can store a search using terms and limits necessary for your topic.
  2. Click Cubby on the sidebar. Last Search displays the last search query, including limits, if used. If your last search is not displayed, your system may not be set to accept cookies.
  3. Edit the name of the search. Above the Store in Cubby button, there is a box where you can edit the name of the search to something manageable yet meaningful.  Examples, Headaches in Preschool Children, Dr. Murphy's Arthritis Update.
  4. Click on Store in Cubby.
Note:
  1. Links to "Related Articles" cannot be stored as a Cubby Stored Search.
  2. History numbers (e.g., #3) cannot be used in Cubby Stored Searches.
  3. Dates and date ranges are not recommended for Stored Searches.
  4. Stored searches are numbered and listed in descending order according to the date and time they were originally stored.
  5. The maximum number of stored searches is 100 per User Name.
  6. Any term from a field other than title or abstract, on an in process or publisher supplied record, may cause the retrieval of a citation a second time.  For example when a term appears only in the [ad] field.
  7. Stored Searches can not be edited.
Stored Search Information
To review information about a stored search, click on the search name. Stored Search Information includes the search name, date and time last updated, database searched, search terms, and field limits, when applicable. Click Search to run the search without update limits. This will not change the latest date and time for this Stored Search.

Updating Cubby Stored Searches
It is easy to check for new items since your last update.

  1. Select the stored search(es) you want to update by clicking the check box(es) next to the Cubby Search Name.  To select all searches click the Select/Deselect All check box.
  2. Click "What's New for Selected." The Cubby displays the list of searches you selected along with an additional column indicating the number of new items retrieved since the last time you checked. If there are no new items, the Cubby displays "0 new."
  3. Click # new to link to the new items. Clicking on this link displays the new items, and updates the stored search in the Cubby with the new Date and Time. If you do not click # new, the search date and time are not updated.
What's New Strategy
The Cubby uses the following strategy, for unqualified searches, to find new citations for your search:
  1. Query AND T1 : T2 [MHDA]
  2. Query [TIAB] AND 1900/00/00 : T1 [EDAT]
  3. #1 NOT #2
Where:
Query = Stored search strategy.
T1 = The date and time the search was last updated.
T2 = Today's date and time.
1900/00/00 = The date that will include all citations. (Note: PubMed includes citations back to the early sixties.)
[MHDA] = The search tag for the MeSH date. This field reflects the date MeSH terms were added to the citation. (Note: until MeSH terms are added, the MHDA value is the same as the EDAT.)
[EDAT] = The search tag for the Entrez date field. This field reflects the date the citation was added to PubMed.
[TIAB] = The search tag for words in the Title and Abstract fields.
The Details button will not display on the results screen after updating a Cubby search because three separate search strategies are run as explained above.

Example: The stored search strategy is "dna repair." The search was last updated on 2000/07/01 at 9:30 am. Today's date and time is 2000/08/01 at 11:00 am.

  1. dna repair[MeSH Terms] OR dna repair[Text Word] AND "2000/07/01  9:30" : "2000/08/01 11:00" [MHDA]
  2. dna repair[TIAB] AND "1900/00/00" : "2000/07/01 9:30" [EDAT]
  3. #1 NOT #2
Note: Cubby Stored Searches that include search field tags use an abbreviated What's New search strategy to ensure all citations are retrieved.

Strategies that include the Search Field Tags AU, PS, IP, TA, LA, PG, TI, TIAB, or VI use the strategy:  Query AND T1 : T2 [EDAT]

Strategies that include the Search Field Tags AD, FILTER, SB, RN, MAJR, MESH, PTYP, SI, SH, NM, or TW, or Tags from both lists, use the strategy:  Query AND T1 : T2 [MHDA]

Deleting Stored Searches
Select the stored search(es) you want to delete by clicking the check box next to the Cubby Search Name. Next, click "Delete Selected Searches." You can select and delete multiple searches at a time.

LinkOut Preferences
Login, or Register for Cubby.

LinkOut is a service that provides links from items retrieved from Entrez databases to information providers. In PubMed, the link to the citation provider displays with the abstract and citation format of an item. All other links to providers from a retrieved item display on the LinkOut display page. Use Cubby LinkOut Preferences to customize which links display. Whenever you login to the Cubby, PubMed will display LinkOut providers according to your specifications.

Setting your Preferences:
You can change how provider links are displayed by adding an icon or hiding a link from LinkOut.

Add Icon: Links to providers' web sites can display on the fuller display formats (e.g., Abstract, GenBank) as icons. The Add Icon option controls which provider icons are displayed. The default is for only the citation provider and PubMed Central icons to be display with these formats.

Hide from LinkOut: This controls which provider links are displayed on the LinkOut display format. The default is for all the provider links to display on the LinkOut display format for each citation.

Provider Categories
This page lists the categories of LinkOut providers and lets you choose whether or not to display all the providers in a particular category. View Providers by Category
On the Provider Categories page, you can link on the Category Name to see which individual providers are grouped in that category. Each list also allows you to Add Icon/Hide links as described above. Click "Update LinkOut Preferences" to save any changes.

All LinkOut Providers
This page lists all the LinkOut providers in alphabetical order.

My LinkOut Preferences
You can see how your Preferences are set on the My LinkOut Preferences page. The Add Icon/Hide from LinkOut options are also available from this page for providers you have modified. Click "Update LinkOut Preferences" to save any changes.

General LinkOut Notes:

  1. Your LinkOut preferences are in effect only when you are logged into the Cubby. Your Login will remain active for 12 hours.
  2. When you select preferences from a list, this will not be reflected in other provider lists. For example, if you chose to hide all Library LinkOut providers, there will not be a check in the Hide check box for all the libraries on the All Providers list.
  3. The category and individual providers are in separate sections on the page. If you make changes, be sure to click "Update LinkOut Preferences" for that section.
  4. You may not hide the citation provider or PubMed Central icons from the Abstract and Citation display formats.
Document Delivery Services Documents

Displaying
PubMed displays your search results in batches - the default is 20 citations per page.

The Show pull-down menu allows you to increase the number of citations displayed on a single page up to a maximum of 500 items. To do this:

Click on the Select Page numbers to link to other search result pages. The current page number is displayed in red.  Click on >> to see page numbers greater than those displayed, or << to see numbers less than those displayed.

PubMed citations are initially displayed in a summary format. Documents can be viewed in one of six other formats: Summary (default), Brief, Abstract, Citation, MEDLINE and ASN.1. You can choose to display other formats by:


Display Formats
Your citations can be displayed in any of the following formats.  See Search Field Descriptions for an explanation of the fields.

Summary - This format may include: Author name(s), Title, Journal source, Review or Retracted Publication Publication Types,  language if article is non-English, "No abstract available" notation,  PMID and citation status.

Brief - Author name, first 30 characters of the Title, and PMID.

Abstract - This format may include: Journal source, Erratum, Retractions, Comments, Republished data, Updates, Title, language if article is non-English, Authors, Corporate Name, Author Affiliation, Abstract (if present), Publication Types (except for the Journal Article publication type), Personal Name as Subject, PMID and citation status.

Citation - This format may include: Journal Source, Erratum, Retractions, Comments, Republished data, Updates, Title, language if article is non-English, Authors, Corporate Name, Author Affiliation, Abstract (if present), Publication Types (except for the Journal Article publication type), MeSH Terms, Personal Name as Subject, Chemical Substances, SI-databank accession numbers, Grant numbers, PMID and citation status.

MEDLINE - Two character tagged field format for the complete record.  Use this format to download records into reference management programs.

ASN.1 -  ASN.1 (Abstract Syntax Notation One) is an international standard used to achieve inter operability between platforms, including computer-to-computer, pager-to-computer, and many other possible combinations.

XML - EXtensible Markup Language tagged format is a standard maintained by the World Wide Web Consortium (W3C). The XML standard defines a syntax used to create markup languages to specify information structures.

Text
You may display citations as plain text without the sidebar menu and toolbars by clicking on the Text button.   To display citations in a different format, choose the desired format from the pull-down menu, and click Text.  To return to your results in PubMed, use your browser's back button.

Display Order
Citations in PubMed are displayed in Entrez Date order - last in, first out. The Entrez date is the date that a record was initially added to PubMed and should not be confused with the publication date which is the date an article was published.

You can use the Entrez Date pull-down menu to limit your retrieval to a pre-selected range of dates or use the Entrez Date search field tag to specify a single date or date range. The Entrez Date is only displayed on the MEDLINE display format.

The Related Articles link displays citations in ranked order from the most to least relevant compared to the citation you linked from.

Saving
The PubMed Save function creates a text file of your PubMed citations on your computer. The Save button is available on screens with search results. You can save entire search results or selected citations.  If you don't select specific citations before clicking on the Save button, you will create a file on your computer that will contain the entire search results up to a maximum of 10,000 items.

You can also save citations collected from multiple searches by using the Add to Clipboard feature. The Clipboard holds a maximum of 500 items. When you save a file, your browser will prompt you where this file should be placed on your computer, and also give you the opportunity to rename the file.

Importing Citations into a Reference Manager Program:

  1. To import search results into a reference manager program change the Display format to MEDLINE before clicking on the Save button. This format includes the field tags needed for these programs.
  2. Consider changing the .fcgi extension to .txt if you wish to open the file in a text editor, word processing  or reference manager program.
Saving Entire Search Results:
  1. The default for the Save feature is to save the entire retrieval, up to 10,000 items, unless you specifically select citations. For example, if you use the Save button on a screen displaying 1-20 items of 2356, your saved file will contain all 2,356 citations.
  2. Use the Display pull-down menu to select a format.
  3. Click Save and your items will be saved in this format as plain text.
Saving Selected Citations from a Single Search:
  1. Use the Display pull-down menu to select a format.
  2. Click in the check boxes next to each citation you want to save.
  3. You can move to other pages within the search results to make more selections.
  4. Click Save and your selected items will be saved in the Display format as plain text.
Saving Citations from Multiple Searches:
  1. Use the Add to Clipboard function to add either entire search results or selected items to the Clipboard.
  2. The Clipboard can contain up to 500 items.
  3. When ready to Save, click on the Clipboard link to go to that screen.
  4. Use the Display pull-down menu to select a format.
  5. Click Save and your items will be saved in this format as plain text.
Note:
  1. Saving a large retrieval may take several minutes.
  2. To save citations in HTML format use the Save as... function of your browser.  Change the file extension to html.  You will only save the citations displayed on the screen so you may wish to use the Show function and Text button to adjust your display as needed.
See also: Printing
Use the print function of your Web browser to print all the information and citations displayed on your web page. Before printing, consider using Show to increase the number of documents per page so that the total number of documents is displayed on one page (maximum: 500 per page). You can only print the citations from the displayed page.

Printing Selected Citations:

You may want to print selected items from one or more searches on a single page. You can do this by collecting them in PubMed's Clipboard:
 

  1. Click in the box next to each citation you want and then click on Add to Clipboard. The Clipboard can hold up to 500 items.
  2. When you are ready to print, click on the Clipboard link to go there.
  3. Within the Clipboard, display the citations in the format and sort order you want to print.
  4. Use your browser's print function to print the page.
Note:
You may also wish to display your citations as Text to strip the sidebar menu and toolbars prior to printing your results.
Ordering
Order allows you to order the full-text copy of an article from a library in your area using the Order Documents feature of PubMed.

Note:

Prior to using this program you must establish an agreement with a Loansome Doc participating library. Local fees may apply. For information on the medical libraries in your area (or country) that can provide the Loansome Doc service, click on Order Documents from the PubMed sidebar menu, then "Registration" from the Loansome Doc Ordering System screen.
Once you have registered with Loansome Doc, you can order citations, by clicking on the check box to the left of each citation.  When you have finished marking your selections (you may move to other pages within your results), click Order.  You may also use the Clipboard to collect items from multiple searches before ordering.

Note:

For some journals the full-text of articles are available via a PubMed link to the publisher's Web site.  Publisher links for the full-text of the article are displayed on the Abstract or Citation display.   You may also click on LinkOut to the right of each citation in the Abstract, Citation or MEDLINE display.   LinkOut is a PubMed feature that links to outside sources for the full-text of the article, e.g., a publisher's web site, as well as other resources such as biological databases, and sequencing centers.   User registration, a subscription fee, or some other type of fee may be required to access the full-text of articles in some journals.
Links
Related PubMed Articles Link
Each citation in PubMed has a link that will retrieve a pre-calculated set of PubMed citations that are closely related to the selected article.  Click on Related Articles to the right of each citation to display the related set of articles. PubMed creates this set by comparing words from the title, abstract, and MeSH terms using a powerful word-weighted algorithm. Citations are displayed in rank order from most to least relevant with the linked from citation displayed first.

Limits are NOT in effect when you use a Related Articles link.  Notice, after linking on Related Articles, that although the box next to Limits may be checked, there is no yellow bar displaying the Limits in effect.

You can, however, refine the list of Related Articles using PubMed's History feature.  In History you will see the Related Articles retrieval is represented as "Link to PubMed from (PMID of document)."  Use this Search
number in a search.  Examples:

#3 AND english [la]
#14 AND 1996:1999 [dp]

Keep in mind that the list you get with a Related Articles link is displayed in ranked order from most to least
relevant.  Refining the list may remove citations that are most relevant.

LinkOut - LinkOut allows publishers, aggregators, libraries, biological databases, sequence centers, and other Web resources to display links to their sites on items from the Entrez databases.   These links can take you to the provider's site to obtain the full-text of articles or related resources, e.g., consumer health information.  There may be a charge to access the text or information.  The current list of LinkOut providers is available.

Broken Links
Links are supplied to us by the providers; corrections and changes to links are made by the providers and are their responsibility.  Problem links should be reported directly to the provider, you can usually find a contact link at their web site.  Contact the Help Desk if you need assistance finding this information.

A publisher's icon link may display on the Abstract and Citation display formats if they have electronically provided their citation data to PubMed.  Links are only available for publishers that are participating in LinkOut; publishers are responsible for providing working links.  Links to other providers appear on the LinkOut display format.  To see the LinkOut format for a retrieved item, change the Display format to LinkOut, or click on the LinkOut link.

The LinkOut format displays links (if available) by broad categories (e.g., Literature), and then by subject categories, selected by the LinkOut provider.  Full-text provider links also include the form of the article available (e.g., full-text PDF).  Links with an asterisk indicate the LinkOut provider requires a subscription, membership, or fee for access.

Use the Cubby to customize your LinkOut preferences to display only links of interest to you.
 

NCBI Databases
Links to other resources or NCBI databases are available from the buttons to the right of each citation and from the Display pull-down menu.  PubMed will only process the first 500 items with links when using the Display pull-down menu.  The following links are available:

Books - In collaboration with book publishers,  NCBI is adapting textbooks for the web and linking them to PubMed to provide background so users can explore unfamiliar concepts found in search results. The Books link displays a facsimile of the abstract, in which some phrases are hypertext links. These phrases correspond to terms that are also found in the books available at NCBI. Clicking on a hypertext links you to a list of book pages in which the phrase is found.

Other Services

Journal Browser
Use the Journal Browser to search for journals by journal title, title abbreviation, or the International Standard Serial Number (ISSN).  Click on the MEDLINE Abbreviation to search for citations in the journal in PubMed and either the print or electronic ISSN to find the journal in PubList. The list of journals with links to full-text is also included in the browser.  A list of all journals that are included in the PubMed database is available by FTP in the GNU Zip, Uncompressed, UNIX Compress, or PKZIP format.

MeSH Browser
MeSH (Medical Subject Headings) is NLM's controlled vocabulary. It is used to index citations primarily to reflect subject content. PubMed's MeSH Browser is available on PubMed's sidebar menu. This Browser helps you find MeSH terms that you may want to select and use in your searches.  The Browser provides information about each term and displays them in a hierarchical structure. In addition, users can directly attach subheadings and limit terms to a MeSH Major Term.  When you enter a term that is not a valid MeSH term, the MeSH Browser will check against the MeSH Mappings and display the associated MeSH term.

Note:

The PubMed automatic term mapping uses additional see references from the UMLS that can not be viewed in the MeSH browser.
Citation Matcher
The Citation Matcher options allow you to find the citation or the PubMed ID of any article in the PubMed database using bibliographic information. Clinical Queries
This specialized search query with built-in search research methodology filters is intended for clinicians. Four study categories or filters are provided: therapy, diagnosis, etiology and prognosis. Two emphasis categories or filters are provided: sensitivity (includes relevant articles but probably some less relevant) and specificity (more precise articles, with less retrieval).

For More Assistance

Customer Support
If you need more assistance, please click on Write to Help Desk or send an e-mail to custserv@nlm.nih.gov.  You may also contact the NLM Customer service desk at 1-888-346-3656 (1-888)- FINDNLM.  Hours of operation are:
Monday - Friday from 8:30am - 8:45pm and Saturday from 10:00am - 5:00pm Eastern time.

NLM Publications on PubMed
        Tutorial
        NLM PubMed Training Manuals
        NLM Technical Bulletin

References

Search Field Descriptions and Tags (in alphabetical order)

- Affiliation [AD] Institutional affiliation and address of the first author, and grant numbers. The MEDLINE ID (Identification Number) field that contains grant or contract numbers is also searchable using the search field tag [ad], e.g., LM05545/LM/NLM [ad]. All three pieces of the ID field (actual number, grant acronym, and institute mnemonic) are each individually searchable. More precise retrieval results from searching on the grant acronym, e.g., LM for NLM sponsored grants, rather than the institute mnemonic, e.g., NLM, because of the occurrence of the mnemonic in the street or email portion of the address. In those cases where the grant acronym is also a state postal abbreviation such as CA search this way to eliminate false drops from the state; ca [ad] and nci [ad].

- All Fields [ALL] Includes all searchable PubMed fields. However, only terms where there is no match found in one of the Translation tables or Indexes via the Automatic Term Mapping process will be searched in All Fields.  PubMed ignores stopwords from search queries.

- Author Name [AU]  Various limits on the number of author names included in the MEDLINE citation have existed over the years (see NLM policy on author names). MEDLINE does not list the full name.  The format to search for an author name is: last name followed by a space and up to the first two initials followed by a space and a suffix abbreviation, if applicable, all without periods or a comma after the last name (e.g., fauci as or o'brien jc jr). Initials and suffixes may be omitted when searching.  PubMed automatically truncates on an author's name to account for varying initials, e.g., o'brien j [au] will retrieve o'brien ja, o'brien jb, o'brien jc jr, as well as o'brien j. To turn off this automatic truncation, enclose the author's name in double quotes and qualify with [au] in brackets, e.g., "o'brien j" [au] to retrieve just o'brien j.

- EC/RN Number [RN] Number assigned by the Enzyme Commission to designate a particular enzyme or by the Chemical Abstracts Service (CAS) for Registry Numbers.

- Entrez Date [EDAT] Date the citation was added to the PubMed database.  The Entrez Date is set to the Publication Date on citations before September 1997 when this field was first added to PubMed.  Citations are  displayed in Entrez Date order which is last in, first out. Dates or date ranges must be entered using the format YYYY/MM/DD [edat], e.g. 1998/04/06 [edat] . The month and day are optional (e.g., 1998 [edat] or 1998/03 [edat]). To enter a date range, insert a colon (:) between each date (e.g., 1996:1997 [edat] or 1998/01:1998/04 [edat]).

Note:

The Entrez Date will remain unchanged and is not updated to reflect the date a Publisher Supplied record is elevated to in process or when an in process record is elevated to MEDLINE. Therefore, use caution when your strategy includes only MeSH terms and a date or date range using the search field tag, [edat], because the addition of MeSH terms to a record will not change the Entrez Date [edat].
- Filter [FILTER] Technical tags used by LinkOut providers to qualify holdings.

Use the following query to find all the LinkOut links in PubMed:

loall [filter]

You can also use Preview/Index to browse the index of LinkOut providers. Select Filter from the All Fields pull-down menu, enter 'lo' in the box, and click Index. PubMed displays an alphabetic list of all the LinkOut entries in the Index.

The 'loprov' entries are for each of the LinkOut providers . The 'losubj' and 'loattr' entries are the same links indexed by Subject Types and Attributes. The  'loftext' are for entries that include a link to the online full-text of a journal citation.

- Issue [IP] The number of the journal issue in which the article is published.

- Journal Title [TA] The journal title abbreviation, full journal name, or ISSN number (e.g., J Biol Chem, Journal of Biological Chemistry, 0021-9258). The Journal Browser is also available from the PubMed homepage sidebar to look up the full name, abbreviation, and ISSN number of a journal. If a journal name contains parentheses or brackets, enter the name without the parentheses or brackets, e.g., enter J Hand Surg [Am] as J Hand Surg Am.

- Language [LA] The language in which the article was published. Note that many non-English articles have English language abstracts. You can either enter the language or enter just the first three characters of most languages, e.g., chi [la] retrieves the same as chinese [la]. The most notable exception is jpn [la] for Japanese.

- MeSH Date [MHDA]  The date the citation was indexed with MeSH Terms and elevated to MEDLINE for citations with an Entrez Date after March 4, 2000.  The MeSH Date is initially set to the Entrez Date when the citation is added to PubMed. If the MeSH Date and Entrez Date on a citation are the same, and the Entrez Date is after March 4, 2000, the citation has not yet been indexed.  Dates or date ranges must be entered using the format YYYY/MM/DD [mhda], e.g. 2000/03/15 [mhda] . The month and day are optional (e.g., 2000 [mhda] or 2000/03 [mhda]). To enter a date range, insert a colon (:) between each date (e.g., 1999:2000 [mhda] or 2000/03:2000/04 [mhda]).

- MeSH Major Topic [MAJR] A MeSH term that is one of the main topics discussed in the article. See MeSH Terms below.

- MeSH Terms [MH] NLM's Medical Subject Headings controlled vocabulary of biomedical terms which is used to describe the subject of each journal article in MEDLINE. MeSH contains more than 19,000 terms and is updated annually to reflect changes in medicine and medical terminology.  MeSH terms are arranged hierarchically by subject categories with more specific terms arranged beneath broader terms.  PubMed allows you to view this hierarchy in the MeSH Browser.

Skilled subject analysts examine journal articles and assign to each the most specific MeSH terms applicable -- typically ten to twelve. Applying the MeSH vocabulary ensures that articles are uniformly indexed by subject, whatever the author's words.

Notes on MeSH Terms and Major MeSH Topic search fields:

  1. To search the term as a MeSH term, it must be qualified using the search field tags, e.g., [mh] for MeSH Terms or [majr] for MeSH Major Topic. Any term so qualified is checked against the MeSH Translation table. The MeSH translation table includes concepts that may map to two or more MeSH terms.  To turn off this mapping enclose the MeSH term in double quotes and qualify with [mh], e.g., "cold" [mh].
  2. MeSH terms are arranged hierarchically by subject categories with more specific terms arranged beneath broader terms. MeSH terms in PubMed automatically include the more specific MeSH terms in a search.
  3. MeSH/Subheading Combinations:  To directly attach subheadings use the format MeSH Term/Subheading, e.g., neoplasms/diet therapy [majr]. You may also use the MEDLINE two letter subheading abbreviations, e.g., neoplasms/dt [mh], etc. Only one subheading may be directly attached to a MeSH term.  For a MeSH/Subheading combination, PubMed always includes the more specific terms arranged beneath broader terms for the MeSH term and also includes the more specific terms arranged beneath broader subheadings.. The broader subheading or one of its indentions will be directly attached to the MeSH term or one of its indentions. For example, hypertension/therapy also retrieves hypertension/diet therapy; hypertension/drug therapy; hypertension, malignant/therapy; hypertension, malignant/drug therapy and so on as well as hypertension/therapy.
  4. To turn off the automatic inclusion of the more specific terms, use the syntax [field:noexp], e.g., hypertension [mh:noexp], or hypertension [majr:noexp], or hypertension/therapy [mh:noexp]. The latter example turns off the more specific terms in both parts, searching for only the one subheading therapy attached directly to only the one MeSH term hypertension.
  5. If a MeSH term contains parentheses, enter the name without the parentheses, e.g., enter the MeSH term Earth (Planet) as earth planet [mh].
- Page Number [PG] Enter only the first page number that the article appears on. The citation will display the full pagination of the article but this field is searchable using only the first page number.

- Personal Name as Subject [PS] Use this search field tag to limit retrieval to where the name is the subject of the article, e.g., varmus h [ps]. The search rules for Author [au] apply to this field, see Author Name field. To restrict a search to the Personal Name as Subject field users must include the search field tag, [ps].  This field is not in the Limits All Fields pull-down menu because the data are actually indexed as part of the Text Word [tw] search field.

- Publication Date [DP] The date that the article was published. Dates or date ranges must be searched using the format YYYY/MM/DD [dp], e.g. 1998/03/06 [dp] . The month and day are optional (e.g., 1998 [dp] or 1998/03 [dp]). To enter a date range, insert a colon (:) between each date (e.g., 1996:1998 [dp] or 1998/01:1998/04 [dp]).

Note:

Journals vary in the way the publication date appears on an issue. Some journals include just the year, whereas others include the year plus month or year plus month plus day. And, some journals use the year and season (e.g., Winter 1997). The publication date in the citation is recorded as it appears in the journal. It is recommended that you search only by year (e.g., 1996 [dp] or 1995:1997 [dp]).
- Publication Type [PT] Describes the type of material the article represents (e.g., Review, Clinical Trial, Retracted Publication, Letter), see full listing.

- Secondary Source ID [SI] The SI field identifies secondary source databanks and accession numbers of molecular sequences discussed in MEDLINE articles.  The field is composed of the source followed by a slash followed by an accession number, e.g., genbank [si], AF001892 [si], genbank/AF001892 [si].

- Subheadings [SH] Subheadings are used with MeSH terms to help describe more completely a particular aspect of a subject. For example, the drug therapy of asthma is displayed as asthma/drug therapy, see MeSH/Subheading Combinations.  The Subheading field allows users to "free float" subheadings, e.g., hypertension [mh] AND toxicity [sh]. Subheadings automatically include the more specific subheading terms under the term in a search. To turn off this automatic feature, use the search syntax [sh:noexp], e.g., therapy [sh:noexp].  In addition, you can enter the MEDLINE two letter subheading abbreviations rather than spelling out the subheading, e.g., dh [sh] = diet therapy [sh].

- Subset [SB] PubMed includes all the journal citations from MEDLINE. Another component of PubMed are citations that are electronically supplied by publishers directly into PubMed. As a result, your search retrieval may include publisher-supplied citations, indicated by the tag, [PubMed - as supplied by publisher], in process citations indicated by the tag, [PubMed -  in process], or MEDLINE citations indicated by the tag [PubMed - indexed for MEDLINE].  The citation status subsets are mutually exclusive.

There are also three subject subsets available:  AIDS, Complementary Medicine, and Toxicology.  Each uses its own specialized search strategy  developed by NLM. The AIDS and Toxicology subsets aid in the retrieval of citations on these topics.  The Complementary Medicine subset was created for CAM on PubMed, a joint project between NLM and the National Center for Complementary and Alternative Medicine  to facilitate searching for articles in this subject area.  You may also limit citations with full-text links to PubMed Central.

Limit your retrieval to one or more of these subsets using the search field tag [sb]:

MEDLINE - medline [sb]
In process  - in process [sb]
Publisher - publisher [sb]
AIDS - aids [sb]
Toxicology - tox [sb]
Complementary and Alternative Medicine - cam [sb]
PubMed Central - medline pmc [sb]
- Substance Name [NM] The name of a chemical discussed in the article. Synonyms to the Supplementary Concept Substance Name will automatically map when qualified with [nm]. This field was implemented in mid-1980. Many chemical names are searchable as MeSH terms before that date.

- Text Words [TW] Includes all words and numbers in the title and abstract, and MeSH terms, subheadings, chemical substance names, personal name as subject, and MEDLINE Secondary Source (SI) field. The Personal Name of Subject field can also be searched directly using the search field tag [ps], e.g., nightingale f [ps].

- Title Words [TI] Words and numbers included in the title of a citation.

- Title/Abstract Words [TIAB] Words and numbers included in the title and abstract of a citation.

- Unique Identifiers [UID]  PubMed Unique Identifier PMID and MEDLINE Unique Identifier UI  To search for either the PMID or UI simply type in the number with or without the search field tag [uid]. You can search for several ID numbers by entering each number in the query box separated by a space (e.g., 95091318 97465762), PubMed will OR the terms together.

To search in combination with other terms you must enter the search field tag, e.g., smith [au] AND (10403340 [uid] OR vaccines [mh]).

- Volume [VI] The number of the journal volume in which an article is published.

Subheadings
Abnormalities  AB   Manpower  MA
Administration and Dosage  AD   Metabolism  ME
Adverse Effects AE   Methods  MT
Agonists  AG   Microbiology  MI
Analogs and Derivatives  AA   Mortality MO
Analysis  AN   Nursing NU
Anatomy and Histology  AH Organization and Administration OG
Antagonists and Inhibitors  AI   Parasitology  PS
Biosynthesis  BI   Pathogenicity  PY
Blood Supply BS   Pathology PA
Blood  BL   Pharmacokinetics  PK
Cerebrospinal Fluid  CF   Pharmacology  PD
Chemical Synthesis  CS   Physiology  PH
Chemically Induced  CI   Physiopathology  PP
Chemistry  CH   Poisoning PO
Classification  CL   Prevention and Control  PC
Complications  CO   Psychology  PX
Congenital  CN   Radiation Effects  RE
Contraindications  CT   Radiography  RA
Cytology  CY   Radionuclide Imaging  RI
Deficiency  DF   Radiotherapy  RT
Diagnosis DI   Rehabilitation  RH
Diagnostic Use  DU   Secondary SC
Diet Therapy  DH   Secretion  SE
Drug Effects  DE   Standards  ST
Drug Therapy  DT   Statistics and Numerical Data  SN
Economics  EC   Supply and Distribution  SD
Education  ED   Surgery  SU
Embryology  EM   Therapeutic Use  TU
Enzymology  EN   Therapy  TH
Epidemiology EP   Toxicity  TO
Ethnology  EH   Transmission  TM
Etiology  ET   Transplantation  TR
Genetics  GE   Trends  TD
Growth and Development  GD   Ultrasonography  US
History  HI Ultrastructure  UL
Immunology  IM   Urine  UR
Injuries  IN   Utilization  UT
Innervation  IR   Veterinary  VE
Instrumentation  IS   Virology  VI
Isolation and Purification  IP      
Legislation and Jurisprudence  LJ      

Families of Subheading Explosions
 
adverse effects etiology physiology
    poisoning
    chemically induced
    genetics
    toxicity 
    complications
    growth and development
analysis 
      secondary
    immunology
    blood 
    congenital
    metabolism
    cerebrospinal fluid 
    embryology
      biosynthesis
    isolation and purification 
    genetics
      blood
    urine 
    immunology
      cerebrospinal fluid
anatomy and histology 
    microbiology
      deficiency
    blood supply 
      virology
      enzymology
    cytology 
    parasitology
      pharmacokinetics
      pathology 
    transmission
      urine
      ultrastructure 
 metabolism
    physiopathology
    embryology 
    biosynthesis
    secretion
      abnormalities 
    blood
  
    innervation 
    cerebrospinal fluid
 statistics and numerical data
chemistry
    deficiency
    epidemiology
    agonists 
    enzymology
      ethnology
    analogs and derivatives 
    pharmacokinetics
      mortality
    antagonists and inhibitors 
    urine
    supply and distribution
    chemical synthesis 
 microbiology
    utilization
complications
    virology
  
    secondary 
 organization and admin surgery
 
    economics
    transplantation
cytology 
    legislation and juris
  
    pathology
    manpower
 therapeutic use
    ultrastructure
    standards
    admin and dosage
 
    supply and distribution
    adverse effects
diagnosis
    trends
    contraindications
    pathology 
    utilization
    poisoning
    radiography 
 pharmacology  
    radionuclide imaging
    admin and dosage
 therapy
    ultrasonography 
    adverse effects
    diet therapy
 
      poisoning
    drug therapy
embryology 
      toxicity
    nursing
    abnormalities 
    agonists
    prevention and control
 
    antagonists and inhib
    radiotherapy
epidemiology 
    contraindications
    rehabilitation
    ethnology 
    diagnostic use
    surgery
    mortality
    pharmacokinetics
      transplantation

NLM Author Indexing Policy:

NLM's author indexing policy was and is as follows:

Note:
Until 1990, only five transliterated (Japanese and Cyrillic) author names were entered.  Since 1990, the first ten transliterated author names have been entered.  Chinese ideograms for co-authors are not transliterated at all if the journal lists only a single transliterated name in the table of contents.
Publication Types
      Addresses
      Bibliography
      Biography
      Classical Article [for republished seminal articles]
      Clinical Conference [for reports of clinical case conferences only]
      Clinical Trial [includes all types and phases of clinical trials]
      Clinical Trial, Phase I
      Clinical Trial, Phase II
      Clinical Trial, Phase III
      Clinical Trial, Phase IV
      Congresses
      Controlled Clinical Trial
      Randomized Controlled Trial
      Comment [for comment on previously published article]
      Consensus Development Conference
      Consensus Development Conference, NIH
      Corrected and Republished Article [consider Published Erratum]
      Dictionary
      Directory
      Duplicate Publication [duplication of material published elsewhere]
      Editorial
      Festschrift [for commemorative articles]
      Guideline [for administrative, procedural guidelines in general]
      Historical Article [for articles about past events]
      Interview
      Journal Article [excludes Letter, Editorial, News, etc.]
      Lectures
      Legal Cases [includes law review, legal case study]
      Letter [includes letters to editor]
      Meeting Abstract
      Meta-Analysis [quantitative summary combining results of independent studies]
      Multicenter Study
      News [for medical or scientific news]
      Newspaper Article
      Overall [collection of articles; consider Meeting Report]
      Periodical Index [for cumulated indexes to journals]
      Practice Guideline [for specific health care guidelines]
      Published Erratum [consider Corrected and Republished Article]
      Retracted Publication [article later retracted by author]
      Retraction of Publication [author's statement of retraction]
      Review [includes all reviews; consider specific types]
      Review, Academic [comprehensive, critical, or analytical review]
      Review, Multicase [review with epidemiological applications]
      Review of Reported Cases [review of known cases of a disease]
      Review Literature [general review article; consider other reviews]
      Review, Tutorial [broad review for non-specialist or student]
      Scientific Integrity Review [U.S. Office of Scientific Integrity reports]
      Technical Report
      Twin Study [for studies of twins]
 

Stopwords
a during latter presently though
about each latterly previously through
above ec lb primarily throughout
abs ed ld promptly thru
accordingly effected letter pt thus
across eg like quickly to
after either ltd quite together
afterwards else made rather too
again elsewhere mainly readily toward
against enough make really towards
all especially many recently try
almost et may refs type
alone etc me regarding ug
along ever meanwhile relate under
already every mg said unless
also everyone might same until
although everything ml seem up
always everywhere mm seemed upon
am except mo seeming us
among find more seems use
amongst for moreover seen used
an found most seriously usefully
analyze from mostly several usefulness
and further mr shown using
another gave much shall usually
any get mug she various
anyhow give must should very
anyone go my show via
anything gone myself showed was
anywhere got namely shown we
applicable gov nearly shows were
apply had necessarily significantly what
are has neither since whatever
arise have never slightly when
around having nevertheless so whence
as he next some whenever
assume hence no somehow where
at her nobody someone whereafter
be here noone something whereas
became hereafter nor sometime whereby
because hereby normally sometimes wherein
become herein nos somewhat whereupon
becomes hereupon somewhere wherever
becoming hers noted soon whether
been herself nothing specifically which
before him now still while
beforehand himself nowhere strongly whither
being his obtained studied who
below how of sub whoever
beside however off substantially whom
besides hr often such whose
between i on sufficiently why
beyond ie only take will
both if onto tell with
but ii th within
by iii other than without
came immediately others that wk
can importance otherwise the would
cannot important ought their wt
cc in our theirs yet
cm inc ours them you
come incl ourselves themselves your
compare indeed out then yours
could into over thence yourself
de investigate overall there yourselves
dealing is owing thereafter yr
department it own thereby  
depend its oz therefore  
did itself particularly therein  
discover just per thereupon  
dl keep perhaps these  
do kept pm they  
does kg precede this  
done km predominantly thorough  
due last present those  

MEDLINE Display Format

The purpose of this table is to define the data tags that comprise PubMed MEDLINE display format. The tags are presented in alphabetical order. Some of the tags (e.g., CIN) are not mandatory and therefore will not be found in every PubMed MEDLINE display format. Other tags (e.g., AU, MH, RN) may occur multiple times in one record.

Not all fields are searchable in PubMed. Information on searching with tags is available at Search Field Descriptions and Tags.
 

Tag
Name
Description
AB
 Abstract Abstract.
AD
 Affiliation Institutional affiliation and address of the first author, and grant numbers.
AID
 Article Identifier Article ID values may include the pii (controlled publisher identifier) or doi (Digital Object Identifier).
AU
 Author Name Authors' names.
CI
 Copyright Information Copyright statement.
CIN
 Comment In Reference containing a comment about the article.
CN
 Collective Name Corporate author or group names with authorship responsibility.
CON
 Comment On Reference upon which the article comments.
CY
 Country The place of publication of the journal.
DA
 Date Created Used for internal processing at NLM.
DCOM
 Date Completed Used for internal processing at NLM.
DEP
 Date of Electronic Publication Electronic publication date.
DP
 Publication Date The date the article was published.
EDAT
 Entrez Date The date the citation was added to PubMed.
EIN
 Erratum In Reference containing a published erratum to the article.
GS
 Gene Symbol Abbreviated gene names (used 1991 through 1996).
ID
 Identification Number Research grant numbers, contract numbers, or both that designate financial support by any agency of the US PHS (Public Health Service).
IP
 Issue  The number of the issue, part, or supplement of the journal in which the article was published.
IS
 ISSN  International Standard Serial Number of the journal.
JC
 Journal Title Code MEDLINE unique three-character code for the journal.
JID
 NLM Unique ID Unique journal ID in NLM's catalog of books, journals, and audiovisuals.
LA
 Language The language in which the article was published.
LR
 Last Revision Date The date a change was made to the record during a maintenance procedure.
MH
 MeSH Terms NLM's controlled vocabulary.
MHDA
 MeSH Date The date MeSH terms were added to the citation. The MeSH date is the same as the Entrez date until MeSH are added.
PG
 Page Number The full pagination of the article.
PHST
 Publication History Status Date History status date.
PMID
 PubMed Unique Identifier Unique number assigned to each PubMed citation.
PS
 Personal Name as Subject Individual is the subject of the article.
PST
 Publication Status Publication status. 
PT
 Publication Type The type of material the article represents.
RF
 Number of References Number of bibliographic references for Review articles.
RIN
 Retraction In Retraction of the article.
RN
 EC/RN Number Number assigned by the Enzyme Commission to designate a particular enzyme or by the Chemical Abstracts Service for Registry Numbers.
ROF
 Retraction Of Article being retracted.
RPF
 Republished From Original article.
RPI
 Republished In Corrected and republished article.
SB
 Journal Subset Code for a specific set of journals.
SI
 Secondary Source Identifier Identifies a secondary source that supplies information, e.g., other data sources, databanks and accession numbers of molecular sequences discussed in articles.
SO
 Source Composite field containing bibliographic information.
TA
 Journal Title Abbreviation Standard journal title abbreviation.
TI
 Title Words The title of the article.
TT
 Transliterated / Vernacular Title  Non-Roman alphabet language titles are transliterated. 
UI
 MEDLINE Unique Identifier Unique number assigned to each MEDLINE citation.
UIN
 Update In Update to the article.
UOF
 Update Of The article being updated.
URLF
 URL Full-Text Link to the full-text of article at provider's website. Links are incomplete. Use PmLink for the complete set of available links.
URLS
 URL Summary Link to the article summary at provider's website. Links are incomplete. Use PmLink for the complete set of available links.
VI
 Volume Journal volume.

Possible Values for the Grant Abbreviation & Institute Acronym Subelements for the ID Field in MEDLINE (1990 Forward)

Two-character
Grant Institute Full Institute
Abbreviation Acronym Name

NATIONAL INSTITUTES OF HEALTH (NIH)

AA NIAAA National Institute on Alcohol Abuse and Alcoholism
AG NIA National Institute on Aging
AI NIAID National Institute of Allergy and Infectious Diseases
AM1 NIADDK National Institute of Arthritis, Diabetes, and Digestive and Kidney Diseases
AR NIAMS National Institute of Arthritis and Musculoskeletal and Skin Diseases
AT NCCAM National Center for Complementary and Alternative Medicine
CA NCI National Cancer Institute 
CO NCI            Office of the Director
CN NCI            Division of Cancer Prevention and Control
CB NCI            Division of Cancer Biology and Diagnosis
CP NCI            Division of Cancer Etiology
CM NCI            Division of Cancer Treatment
CL CLC Clinical Center
CT DCRT Division of Computer Research and Technology
DA NIDA National Institute on Drug Abuse
DC NIDCD National Institute on Deafness and other Communication Disorders
DE NIDR National Institute of Dental Research
DK NIDDK National Institute of Diabetes and Digestive and Kidney Diseases
DS DS Division of Safety, Office of Research Services
ES NIEHS National Institute of Environmental Health Sciences
EY NEI National Eye Institute 
GM NIGMS National Institute of General Medical Sciences
HD NICHD National Institute of Child Health and Human Development
HG NCHGR National Center for Human Genome Research
HL NHLBI National Heart, Lung, and Blood Institute
HV NHLBI            Division of Heart and Vascular Diseases
HB NHLBI            Division of Blood Diseases and Resources
HR NHLBI            Division of Lung Diseases
HI NHLBI            Division of Intramural Research
HO NHLBI            Office of the Director
HC NHLBI            Division of Epidemiology and Clinical Applications
LM NLM National Library of Medicine
MH NIMH National Institute of Mental Health
NR NCNR National Center for Nursing Research
NS NINDS National Institute of Neurological Disorders and Stroke
OD NIH Office of the Director
OR ORS Office of Research Services
RG DRG Division of Research Grants
RR NCRR National Center for Research Resources
RS2 DRS Division of Research Services
TW FIC Fogarty International Center
WH WHI Women's Health Initiative

1 No longer being assigned. New Institutes are AR (NIAMS) and DK (NIDDK).
2 No longer being assigned. Now part of RR (NCRR).
 
Two-character
Grant Abbreviation Institute Acronym Full Institute Name

HEALTH RESOURCES AND SERVICES ADMINISTRATION (HRSA)

AH BHP formerly Division of Associated health Professions
DH BHP formerly Division of Dentistry
MB BHP Division of Disadvantaged Assistance
NU BHP Division of Nursing
PE BHP Division of Medicine
SA BHP Division of Student Assistance
ST OHS Office of Healthy Start

FOOD AND DRUG ADMINISTRATION (FDA)

FD FDA Food and Drug Administration
BA FDA          Center for Biologics Evaluation and Research-
               Bacterial Products
BB FDA          Center for Biologics Evaluation and Research-
               Biochemistry and Biophysics
BC FDA          Center for Biologics Evaluation and Research-
               Blood and Blood Product
BD FDA          Center for Biologics Evaluation and Research-
               Cytokine Biology
BE FDA          Center for Biologics Evaluation and Research- 
               Product Quality Control
BF FDA          Center for Biologics Evaluation and Research- 
               Virology
BG FDA          Center for Biologics Evaluation and Research- 
               Transfusion
BH FDA          Center for Biologics Evaluation and Research- 
               Hematology

CENTERS FOR DISEASE CONTROL AND PREVENTION (CDC)

CE NCIPC National Center for Injury Prevention and Control
CI CID Center of Infectious Diseases
DP NCCDPHP National Center for Chronic Disease and Prevention and 
       Health Promotion
EH NCEH National Center for Environmental Health
OH NIOSH National Institute for Occupational Safety and Health
PS CPS Center for Prevention Services
ALCOHOL, DRUG ABUSE, AND MENTAL HEALTH ADMINISTRATION (ADAMHA)
see codes under Substance Abuse and Mental Health Services Administration and codes AA, DA and MH under National Institutes of Health
Two-character
Grant Abbreviation Institute Acronym Full Institute Name

OFFICE OF THE ASSISTANT SECRETARY OF HEALTH (OASH)

FP OFP Office of Family Planning
MP OMH Office of Minority Health
PG OAPP Office of Adolescent Pregnancy Programs

SUBSTANCE ABUSE AND MENTAL HEALTH SERVICES ADMINISTRATION (SAMHSA)

AS SAMHSA Substance Abuse and Mental Health Services Administration
OA SAMHSA Office of the Administrator, SAMHSA
SM CMHS Center for Mental Health Services
SP CSAP Center for Substance Abuse Prevention
TI CSAT Center for Substance Abuse Treatment

AGENCY FOR HEALTH CARE POLICY AND RESEARCH (AHCPR)

HS AHCPR Agency for Health Care Policy and Research

Source: Information Systems Branch, Division of Research Grants, National Institutes of Health: July 1993

 
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