Skip to main content
It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.

Evidence-Based Medicine: Search Tips

Boolean Logic

Boolean Operators

  • Use AND to connect keywords and refine your search (retrieves sources with both terms)

  • Use OR to connect keywords and broaden your search (retrieves sources with either term)

  • Use NOT to exclude a word (e.g., heart attack NOT stroke)

  • Use quotation marks to retrieve sources with a phrase in the exact order typed e.g., "rural health"


Nesting Search Terms

Place parentheses around terms connected with the Or operator. Nesting words within parentheses tells the database to process the words as part of the overall search. The absence of parentheses around groups of synonyms and similar concepts disconnects the words from the search equation, and searches for the words separately.

headache AND tylenol OR motrin

Searches for publications with headache and

tylenol, and items with motrin


headache AND (tylenol OR motrin)

Searches for publications with headache and

tylenol, and publications with headache and motrin

Medical Subject Headings

PubMed & MeSH

MeSH (Medical Subject Headings) is the National Library of Medicine's (NLM) controlled vocabulary.  NLM is the producer of MEDLINE, which is the primary component of PubMed.  MeSH terms are assigned to articles based on content.  MeSH terms help target a search by:

  • Clarifying context (topical and grammatical) 

  • Capturing synonyms and related terms 

Use the MeSH Database to search for terms.  

Resource Map

Recommended Resources for EBM Publications

In most cases, resource content overlaps and publications can be found across resources.  This table maps evidence types to resources focused on particular types of evidence.  

Evidence Type

Recommended Resource

Clinical Practice Guidelines

UpToDate, Access Medicine, ClinicalKey, Professional Organizations (AAFP, AHRQNIH, etc.)

Systematic Reviews & Meta-Analysis

Cochrane Library, PubMed Clinical Queries, TRIP Database 

Critically Appraised Topics

UpToDate, ClinicalKey, Access Medicine

Primary Research Articles


Inclusion and Exclusion Criteria

Research Parameters

Inclusion and exclusion criteria are required for systematic reviews but can also be used for standard reviews.  In purpose, inclusion and exclusion criteria focus the scope of the research and mitigate bias.  Inclusion criteria are factors a study must have to be included in a review. Exclusion criteria are factors that make a study ineligible to be included in a review. 

Criteria can include:

  • Study design
  • Population
  • Intervention/Exposure
  • Outcome
  • Dates
  • Language


Newton Gresham Library | (936) 294-1614 | (866) NGL-INFO | Ask a Question | Share a Suggestion

Sam Houston State University | Huntsville, Texas 77341 | (936) 294-1111 | (866) BEARKAT
© Copyright Sam Houston State University | All rights reserved. | A Member of The Texas State University System