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Edward G. Miner Library

Graduate Student Guide: Search Basics

Information and tools for URMC Ph.D. and Master's students

Boolean Operators

To learn how to search in specific databases like PubMed or CINAHL, visit the video tutorials tab. 

What are Boolean Operators?

Boolean operators allow you to tell a database how you want it to search for your terms. They will connect your search terms together to either broaden your results (OR) or narrow your results (AND). 

Capital AND, OR, and NOT are your Boolean operators. 

Why do we use Boolean operators?

  • Focus a search when your topic has multiple search terms
  • Connect different pieces of information to build a search that finds what you are looking for
    • (nurse OR nursing) AND burnout

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Using OR

When you use OR in your search you can: 

  • Expand your results
    • OR gives you more!
  • Connect similar terms or concepts using synonyms
    • nurse OR nurses OR nursing 

Combining AND and OR

This chart can be a helpful way to organize and think about your search terms. 

  • As you move across the chart you are connecting those terms with OR
    • nurse OR nurses OR nursing
    • burnout OR job satisfaction OR stress
  • As you move down you connect each concept with AND
    • (nurse OR nurses OR nursing) AND (burnout OR job satisfaction OR stress)

Using AND

When you use AND in your search you can: 

  • Narrow your results
  • Require that ALL terms connected with AND must be in your results
    • Nurse AND burnout AND covid 
  • Use AND to find articles where each of your search concepts intersect. 
  • The blue area below is where nurse AND burnout AND covid intersect. So our results would have all three terms present. 



To communicate Boolean operators effectively, parentheses and nesting are necessary. Nesting will clarify the relationship between your terms. 

  • Use parentheses ( ) to control exactly how the database interprets your Boolean operators
  • Your search is processed left-to-right
  • Terms inside ( ) are processed as a unit, which is called nesting
    • (nurse OR nurses OR nursing) AND (burnout OR job satisfaction OR stress)

Phrase Searching

Using "double quotations" will tell the database that you want it to find the words you typed exactly as you've typed them. This is called phrase searching. 

  • Narrows your results to find precisely the phrase you are searching for 
  • Use caution and don't include too many terms in quotations. 
  • Only use phrases you would expect an author to use in the paper
    • "job satisfaction"
    • "nurse education"
    • "professional development"