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.

Connecting Your Search Terms: Home

How to

Use this guide to understand how to connect your search terms with the words AND, OR and NOT. These terms are also known as Boolean Operators. You will retrieve more meaningful search results by using these connectors.

Using AND

When you combine your search terms with AND you will get documents that contain both of the terms you enter. By doing this, you will get fewer and more specific search results. The AND operator connects different terms. For example, if you are looking for articles on diet for cancer patients, you would enter diet AND cancer in the search box. 

As seen in the figure below, the overlapping purple area represents documents that contain both diet AND cancer.

Using NOT

NOT excludes specific words from a search, returning sources that contain only your first keyword, not the second. For example, if you are looking for articles on cancer but not articles about diet, you may enter your search as: cancer NOT diet  

As seen in the figure below, only the yellow area would be included in search results as only the first term is searched.  Use NOT very carefully as it may eliminate what you really want!

Using OR

When you combine your search terms with OR you will get documents that contain either or both of the terms. By doing this, you will get more search results.  The OR operator is used to connect similar or synonymous terms. For example, if you are just looking for articles on diet you can enter diet OR nutrition in the search box.

As seen in the figure below, the purple area represents documents that contain either diet OR nutrition.

Search in a Database using Boolean Operators

So how do we use these operators when searching in a library database ?

You can combine these operators to get the best results. It is important to group the ORs with parentheses when writing them out.

For example: You are looking for articles that address prevention programs for overweight children in schools.

  • (obesity or overweight) and "school children"
  • obesity AND (children or kids)
  • (obesity or overweight) and "school children" and prevention
Boolean searching is often available in an Advanced Search mode. Here is an example from RaptorSearch

Ask the MC Library

https://library.montgomerycollege.edu

Germantown Campus Library Rockville Campus Library Takoma Park/Silver Spring Campus Library

Humanities and Social Sciences Building 110

240-567-7858

Macklin Tower

240-567-7117

Resource Center 215

240-567-1540