Boolean Operators define the relationships between words or groups of words.
AND-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 text.
OR-BROADENS the search by searching 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.
NOT-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
NESTING:
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)
WILDCARDS: Symbols (? or * or $) will expand the scope of your search:
Example: Search for an alternative spelling (wom*n) = women, woman.
TRUNCATION: Expands search to include all forms of a root word:
Example: using (nurs?) = nurse, nurses, or nursing