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BOOLEAN SEARCHING: AND, OR, NOT

Introduction

The Library's electronic journal databases (and many other databases and search engines) are based on the principles of BOOLEAN LOGIC. Boolean logic refers to the logical relationship of terms. To specify the relationship between terms or phrases, you use connectors such as:

If one does not use connectors between words, databases usually search for the phrase exactly as it is entered.

Juvenile
CRIME

AND

Use AND to search for two or more terms that appear in the same article. Using AND will narrow the focus, making your search more specific. Use AND when you want to find fewer results.

narrow focus
Juvenile CRIME
Hold mouse over image for animation

OR

Use OR to search for two or more terms that do not have to appear in the same article (it can contain one term or the other.) Using OR will expand the focus, making your search broader. Use OR when you want to find more results.

Broad focus
juvenile CRIME
Hold mouse over image for animation

OR is especially useful when you want to search for a term and its synonyms. For example, the term "juvenile" has many synonyms: teenager, youth, adolescent, etc. Instead of doing separate searches for those terms, you can combine them using OR.

NOT

Use NOT to exclude a search term from the results.

narrow Focus
juvenile
CRIME
MURDER
Hold mouse over image for animation

See It In Action

Fill in the boxes below to see how Boolean logic produces different results in Academic Search Premier. To begin, input the terms below (in the order that they appear)

Choose a search term:
Choose a synonym for this term:
Choose another search term:
Choose a term you want to exclude from the results: