Boolean Operators are simple words used as conjunctions to combine or exclude keywords in a search, resulting in more focused and productive results.
They connect your search words together to either narrow or broaden your set of results.
The three basic boolean operators are: AND, OR, and NOT.
Why use Boolean operators?
To focus a search, particularly when your topic contains multiple search terms.
To connect various pieces of information to find exactly what you're looking for.
Use AND in a search to:
Use OR in a search to:
Use NOT in a search to:
Databases follow commands you type in and return results based on those commands. Be aware of the logical order in which words are connected when using Boolean operators:
Stop words are frequently occurring, insignificant words that appear in a database record, article or web page. Common stop words include:
Why should you care about stop words?
How can you avoid using stop words in your search?
Truncation & Wildcards
Truncation, also called stemming, is a technique that broadens your search to include various word endings and spellings. To use truncation, enter the root of a word and put the truncation symbol at the end. The database will return results that include any ending of that root word.
Similar to truncation, wildcards substitute a symbol for one letter of a word. This is useful if a word is spelled in different ways, but still has the same meaning.
A controlled vocabulary is an organized arrangement of words and phrases used to index content and/or to retrieve content through browsing or searching. It typically includes preferred and variant terms and has a defined scope or describes a specific domain.
To find subject headings for your topic:
Look to see if the database has an online thesaurus to browse for subjects that match your topic (check the Help screens).
Another way to find subject headings:
Start with a keyword search, using words/phrases that describe your topic.
Browse the results; choose 2 or 3 that are relevant.
Look at the Subject or Descriptor field and note the terms used (write them down).
Redo your search using those terms.
Your results will be more precise than your initial keyword search.