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.
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.
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!
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.
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.
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