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PubMed - Searching Medical Literature: Advanced Search Techniques

A guide to searching medical literature using PubMed, the MEDLINE search engine from the National Library of Medicine.

PubMed Advanced Search Builder

PubMed: Using the Advanced Search

In this 3 minute video, learn to use PubMed's Advanced Search features to refine your search with the example of a publication date range; and find journal and author names using the autocomplete feature.

PubMed: Using the Advanced Search

Search Techniques - Set Filters or Limits

Databases usually allow you to limit or filter your search results in various ways. These may include:

  • language
  • type of publication (case study, clinical trials, review articles)
  • sex
  • age groups
  • date published
  • peer-reviewed

Search Techniques - Truncation & Wildcard

Most databases use the symbol * or #. Use the database's Help tab for verification of the correct symbol.

Truncation Symbol:  Uses root of the word…

Example:  pharm*

Finds pharmacology, pharmacy, pharmaceutical, etc.

Example:  injur*

Finds injured, injury, injuries, etc.

Wildcard Symbol:  Allows for multiple spellings of a word...

Example: sul*ur

Finds sulphur and sulfur

Example: orthop*dic

Finds orthopedic and orthopaedic

Search Techniques - Other Search Operators

Proximity operators:  Proximity (or adjacency) operators allow you to search by phrase or with two or more words in relation to one another. Use the database's Help tab for to verify what symbol to use.

Near (n): if it does not matter which word appears first.

Example: Prozac n3 adverse effects

Finds Prozac within three words of adverse effects

With (w): if your terms must be in the same order in which they are entered.

Example: physical w1 therapy

Finds records where the word physical is listed first, followed by the word therapy, and where no more than one word separates the two terms.

Exact Phrase: Use quotation marks to search for an exact phrase.

Example:  "persian cat"

Finds information on cats that are the Persian breed, not just cats in relation to anything Persian.

Stop words

and, if, or, the, a, for

Boolean Operators

Boolean logic is a system that allows a searcher to set relationships between keywords or concepts when searching. The most commonly used Boolean commands are AND, OR, and NOT. Parentheses can be used to specify the relationship further. Using these operators can make your searches more precise and save time.

Tells the database that you only want articles that contain ALL of the search terms

smoking AND nicotine

Tells the database that you want all articles that contain EITHER of the terms

smoking OR nicotine

Tells the database that you do not want any articles that contain a certain term

smoking NOT nicotine

Tells the database that you want articles with EITHER of two terms AND another

(smoking OR nicotine) AND cancer