Boolean Search Operators

What is a Boolean Search?

Boolean searching is the most effective “advanced” search technique to improve your search results by making them more relevant and precise. It uses tools called operators or modifiers to limit, expand, or refine your set of results. The three basic Boolean operators are AND, OR, and NOT.

All library databases will understand Boolean operators. The chart below briefly explains these tools and their functions.

Table 1.2. Boolean Operators and Their Functions
AND Instructs the database to bring back results that only contain both search terms. nursing AND leadership
OR with () Instructs the database to bring back search results that contain either or both search terms. Whenever you join keywords with OR, enclose them with parentheses (). (teenagers OR adolescents)
NOT Instructs the database to exclude results that contain a specific search term or terms. Canada NOT (“United States” OR America)
“” Instructs the database to search for a whole phrase; keeps separate words together and in order. “outpatient care”
* Instructs the database to broaden your search to include multiple endings and spellings of a word. genetic* – will search genetic, genetics, genetically

The screenshot below shows an example of an advanced search in Novanet using Boolean operators and modifiers.


Screenshot of the Novanet Advanced Search using Boolean Operators


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Introduction to the Library and Library Research by Margaret Vail and Karina Espinosa is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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