Answered By: Sara Marks
Last Updated: Sep 06, 2017     Views: 6

The search engine of online journal indexes are based on a system of combining terms using Boolean operators (AND, OR, NOT) to control the results of your search. To use two or more Boolean operators, you need to know how to use a technique called nesting.

  • Use AND to narrow a search since both terms must be present in the articles you retrieve.
children AND adolescents

The black area represents only those articles that have both children and adolescents present.

  • Use OR to expand a search. Your search will retrieve articles with EITHER of the terms. OR is most often used to combine synonyms or like terms.

memory OR recall

The black area represents articles that have either or both terms present.
  • Use NOT to exclude a term. Articles with the first term will be retrieved. Articles with the second term will not.

children NOT adolescents

The black area represents those articles that have the term children but not the term adolescents.


Nesting involves using parentheses so the search engine will perform the Boolean operations in the sequence you intend. This technique allows you to build a complex search using two or more operators (AND, OR, NOT, NEAR, WITH). 

In this search the OR operation is nested and will be performed first. Then the AND operation will be performed. The search results are represented by the yellow i.e. articles on risk taking or risky behavior and adolescents as well as items on risk taking or risky behavior and teenagers.