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Nursing and Allied Health: Pubmed / Medline Search Basics

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Acceptable Document Types (Undergraduate)

PubMed contains many types of documents


Undergraduate research assignments at Northwestern State University College of Nursing allow the document types.  In Pubmed My profile, you can specify only these types of documents.  Specifying these document types omits over 50 other document types.  This ensures you retrieve only those types of articles acceptable to your professors.

Acceptable PubMed Document Types:
  • Classical Article
  • Comparative Study
  • Electronic, Supplementary Material
  • Introductory Journal Article
  • Journal Article
  • Legal Case
  • Multicenter Study
  • Observational Study
  • Practice Guidelines
  • Scientific Integrity Review
  • Validation Study

After setting up your NCBI Account, you specify document types.  When you sign in to PubMed NCBI, your search results are automatically filtered to these document types.  This is a screenshot of  your MyNCBI Dashboard document filter types:  

You may also set up other filters to simply your search results:


How do I search Pubmed?
PubMed® comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.


Search PubMed
PubMed Frequently Asked Questions (FAQs)


How Do I Search PubMed ?




  1. Identify the key concepts for your search. 
  2. Enter the terms (or key concepts) in the search box.
  3. Press the Enter key or click Search.



  • Best Match sort order uses a state-of-the-art machine learning algorithm to place the most relevant citations at the top of your results.
  • An autocomplete feature displays suggestions as you type your search terms. This feature is based on PubMed query log analysis described in " Finding Query Suggestions for PubMed ."
  • A spell checking feature suggests alternative spellings for search terms that may include misspellings.
  • A citation sensor displays suggested results for searches that include terms characteristic of citation searching, e.g., author names, journal titles, publication dates, and article titles.
Find a specific citation


  • Copy and paste the article title (without punctuation) into the search box; Select TITLE from the pull-down menu
  • Enter the author name in the format: LAST NAME, FIRST INITIAL; Select AUTHOR from the pull-down menu
  • Enter the JOURNAL NAME (without punctuation); Select JOURNAL NAME from the pull-down menu; Enter the year the article was published in the search box;  Combine results of the JOURNAL NAME and year.
  • The citation sensor incorporates a fuzzy matching algorithm and will retrieve the best match even if a search includes an incorrect term. You do not need to use FIELD TAGS or Boolean operators.

Limit the number of search results: 


  • Select a citation
  • Click on the abstract page for a citation, see the Similar Articles section for a pre-calculated set of additional PubMed citations closely related to that article.
  • Remove extraneous or specific terms from the search box.
  • Try using alternative terms to describe the concepts you are searching.


Enter the author’s last name and initials without punctuation in the search box, and click Search. 

If you only know the author’s last name, use the author search field tag [au], e.g., brody[au]. 

Names entered using either the lastname+initials format (e.g., smith ja) or the full name format (john a smith) and no search tag are searched as authors as well as collaborators, if they exist in PubMed.

Enter a full author name in natural or inverted order, e.g., julia s wong or wong julia s.

  • Prior to 2002, full author names were not included on PubMed citations, so full author name searches will only retrieve citations from 2002 forward, when the full author name was published in the article. 
  • A comma following the last name for searching is optional. For some names, however, it is necessary to distinguish which name is the last name by using the comma following the last name, e.g., james, ryan.

Omit periods after initials and put all suffixes at the end, e.g., vollmer charles jr

Initials and suffixes are not required. If you include a middle initial or suffix, you will only retrieve citations for articles that were published using the middle initial or suffix.

More information about author searching:

  • To search by author using the search builder, click Advanced search and then select Author from the All Fields menu. The author search box includes an autocomplete feature.
  • You may click an author link on the abstract display to execute a search for the author in PubMed. Results will display using a ranking algorithm if the author name is computationally similar for additional PubMed citations.
  • If an author name includes only stopwords, use the author search field tag [au] to search in combination with other terms, e.g., just by[au] seizure.
  • Author names are automatically truncated to account for varying initials and designations such as Jr. To turn off the truncation, use double quotes around the author's name with the author search field tag [au], e.g., "smith j"[au].
  • Use the search field tag [1au] to search for the first personal author or [lastau] to search for the last personal author name in a citation.

For additional information on author names in PubMed, please see the journal article, "Author Name Disambiguation for PubMed."


Enter one of the following in the search box:

  • full journal title (e.g., molecular biology of the cell)
  • title abbreviation (e.g., mol biol cell)
  • ISSN number, a standardized international code (e.g., 1059-1524)

More information about journal searching: 

  • To search by journal using the search builder, click Advanced search and then select Journal from the All Fields menu. The journal search box includes an autocomplete feature.
  • To find full journal names, use the NLM Catalog, or mouseover the journal title abbreviation on the citation (available in abstract view).
    1. Click Journals in NCBI Databases on the PubMed homepage.
    2. Enter the journal name and click Search.
  • Use the journal search field tag [ta] to limit your search to the journal only, e.g., gene therapy[ta], scanning[ta]
  • Searching with the full journal title or abbreviation is recommended for complete retrieval of indexed items; older citations may not have an ISSN.
  • If a journal title or abbreviation includes a special character (e.g., parentheses, brackets, &), enter the title or abbreviation without the special characters. For example, to search by the journal abbreviation j hand surg [am], enter j hand surg am.
  • Searching for a journal will automatically map to the official journal title and the title associated with an alternative title, if one exists. To turn off this automatic mapping enter the journal in double quotes and tag with [ta], e.g., "science"[ta].

A list of journals included in PubMed is available by FTP.

Searching by date


Using the results timeline


Click and drag the sliders on the Results by Year timeline to change the date range for your search.

Note: The Results by Year timeline counts all publication dates for a citation as supplied by the publisher, e.g., print and electronic publication dates. These dates may span more than one year; for example, an article that was published online in November 2018 and published in a print issue in January 2019. This means the sum of results represented in the timeline may differ from the search results count.


Using the search builder


  1. Click Advanced search and use the search builder.
  2. Select a date field from the All Fields menu, e.g., Date – Publication, and enter a single date or a date range in the fill-in-the-blank boxes. Month and day are optional. If you want to search for a date range up to the current date, do not edit the ‘Present’ date box.
  3. Add the date from the builder to the query box.
  4. Once you have finished adding terms to the query box, click Search (or Add to History) to run the search.
Searching by a single date in the search box


Enter dates using the format yyyy/mm/dd [date field]. The month and day are optional.

Use a Boolean operator when combining a date with other search terms.


Use the Boolean operator AND to limit your search to a specific publication date.

cancer AND 2020/06/01[dp]

The available date fields are:

  • Date of Publication [dp] - Date searching includes both print and electronic dates of publication. Searching for a single date does not include items when the electronic date of publication is after the print date.
  • Electronic Date of Publication (if applicable) [epdat]
  • Print Date of Publication (if applicable) [ppdat]
  • Entry Date [edat] - The date the citation first entered PubMed (see Entry Date for exceptions).
  • MeSH Date [mhda] - The date the citation was indexed with MeSH terms.
  • Create Date [crdt] - The date the citation record was first created.

Searching for a date range in the search box

Enter date ranges using a colon (:) between each date followed by a [date field].

Use a Boolean operator when combining a date range with other search terms.


Use the Boolean operator AND to limit your search to a date range.

heart disease AND 2019/01/01:2019/12/01[dp]

Comprehensive searches for a full year should be entered as 2000:2000[dp] rather than 2000[dp] to retrieve citations with a different print and electronic year of publication.

Date range searching includes both print and electronic dates of publication.

Searching for a relative date range

Use the following format to search for a relative date range:

  • term="last X days"[date field]
  • term="last X months"[date field]
  • term="last X years"[date field]

where X is the number of days, months or years immediately preceding today’s date and [date field] is the date field tag: [dp], [edat] or [crdt].

The relative date range search for publication dates will also include citations with publication dates after today's date; therefore, citations with publication dates in the future will be included in the results.

Searching for a phrase


PubMed does not perform adjacency searching. However, many phrases are recognized by the subject translation table used in PubMed's Automatic Term Mapping (ATM). For example, if you enter fever of unknown origin, PubMed recognizes this phrase as a MeSH Term.

You can bypass ATM and search for a specific phrase using the following formats:

  • Enclose the phrase in double quotes: "kidney allograft"
    • If you use quotes and the phrase is not found in the phrase index, the quotes are ignored and the terms are processed using automatic term mapping.
  • Use a search tag: kidney allograft[tw]
    • If you use a search tag and the phrase is not found in the phrase index, the phrase will be broken into separate terms, e.g., "psittacine flight" is not in the phrase index, so a search for psittacine flight[tw] is broken up and translated as: ((("psittaciformes"[MeSH Terms] OR "psittaciformes"[All Fields]) OR "psittacine"[All Fields]) OR "psittacines"[All Fields]) AND "flight"[Text Word]
  • Use a hyphen: kidney-allograft
    • If you use a hyphen and the phrase is not found in the phrase index, the search will not return any results for that phrase.

Phrases may appear in a PubMed record but not be in the phrase index. To browse indexed phrases, use the Show Index feature included in the Advanced Search Builder: select a search field, enter the beginning of a phrase, and then click Show Index.

When you enter search terms as a phrase, PubMed will not perform automatic term mapping that includes the MeSH term and any specific terms indented under that term in the MeSH hierarchy. 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, that are included in the automatic MeSH mapping.

Truncating search terms


To search for all terms that begin with a word, enter the word followed by an asterisk (*): the wildcard character. 

To search for a bound phrase including a truncated term, use the following formats:

  • Enclose the phrase in double quotes and include a star (SHIFT 8) example --  "breast feed*"
  • Use a search tag to search within a field(s): example -- breast feed*[tiab]
  • Use a hyphen for a word variation -- example: breast-feed* OR breastfeed*
Special Rules:


At least four characters must be provided in the truncated term.

The truncated term must be the last word in the phrase.

Truncation turns off automatic term mapping and the process that includes the MeSH term and any specific terms indented under that term in the MeSH hierarchy. 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.

Combining search terms with Boolean operators (AND, OR, NOT)


PubMed applies an AND operator between concepts, e.g., "vitamin c common cold" is translated as vitamin c AND common cold. Enter Boolean operators in uppercase characters to combine or exclude search terms:

  • AND retrieves results that include all the search terms.
  • OR retrieves results that include at least one of the search terms.
  • NOT excludes the retrieval of terms from your search.

PubMed processes searches in a left-to-right sequence. Use parentheses to "nest" concepts that should be processed as a unit and then incorporated into the overall search.

Boolean operators must be used when combining tagged search terms as follows: search term [tag] BOOLEAN OPERATOR search term [tag]. See Search Field descriptions and tags.

  • PubMed uses automatic term mapping to identify concepts. For example, for the search air bladder fistula, 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.
  • Search Details show how a search was translated.

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