While most of know about keywords, Boolean searching is a powerful way to specify your search. Most search engines include this option, though it can look different depending on the database. Based on logic, Boolean operators include the words AND, OR, and NOT and they are used to include or exclude words or .
|AND or +
|Retrieves records that contain
ALL of the search terms.
||Retrieves records that contain
ANY of the search terms, but
does not necessarily include
all of them.
|NOT or -
|Excludes records containing
the second search term.
Just entering a couple of keywords into a search box often results in too few, too many, or irrelevant results.
In order to retrieve the most relevant results, you will need to construct a search string. A search string is a combination of keywords, truncation symbols, and Boolean operators you enter into the search box. The diagram above shows how the different search results overlap.
Almost every search engine has an "Advanced Search" that provides a template for Boolean searching.
Boolean searches allow you to combine words and phrases using the words AND, OR, and NOT. These words are knows as Boolean operators (connectors).They will limit, widen or define your search so that you are less likely to get too many unrelated hits when you search for a subject.
Truncation or wildcards allow you to search for variations of a word or phrase. For example, school* will search for school, schools, and schooling.