Boolean Operators define the relationships between words or groups of words.
Narrows your search and retrieves records containing all of the words it separates.
Example: bedsore and treatment
You may use and again, adding yet another keyword to further narrow your search.
Example: bedsore and treatment and outcome
This will search for all three terms appearing within the text.
Broadens the search by searching the text for synonyms of keywords.
Example: bedsore or decubitus or pressure ulcer
This is a means of broadening your search by using synonyms to cover a wider selection of text.
You are not searching for all the terms as you did with and; you are searching for any of these terms.
Narrows the search by eliminating unnecessary concepts, and by searching for records
that do not contain certain terms.
Example: cancer not lymphoma
In this case, you are eliminating the term lymphoma so that your search results will not have records containing this term.
OTHER BOOLEAN SELECTIONS
You may use any of the three Boolean operators together in a search string:
Example: (bedsore or decubitus) not treatment
decubitus and (treatment or care)
Symbols (? or * or $) will expand the scope of your search:
Example: Search for an alternative spelling (wom*n) = women, woman.
Expands search to include all forms of a root word:
Example: using (nurs?) = nurse, nurses, or nursing.