The large number of citations in many catalogs and databases requires one to limit otherwise broad or general searches in order to retrieve a manageable and pertinent number of results. Conversely, overly narrow search terms can return too few results. One way of solving both problems is to use Boolean operators (AND, OR, NOT), which allow one to limit or expand searches depending on his or her needs.
For example, a search for nursing AND patient safety will return items that contain both "nursing" and "patient safety":
nursing OR patient safety returns items that contain either "nursing" or "patient safety" or both:
nursing NOT patient safety returns items that contain "nursing" but not "patient safety":
An important strategy for one to employ when researching phrasal concepts (e.g., "European Union") or conducting known-item searches for titles:
For example, patient safety will search for patient AND safety.
However, "patient safety" in quotation marks will search for this as a phrase and try to find relevant resources with those words all together.
Nested Searching:When pairing two or more keywords with another keyword, it is helpful to "nest" the former terms within a larger Boolean search.
For example, (nursing OR hospitals) AND patient safety will return results for patient safety and any one (or both) of the parenthetical terms.
(Many catalogs or databases will have an "advanced search" option, which provides multiple search bars to facilitate nested searching.)
Truncation and Wildcards:
Most catalogs and databases enable users to search variations of keywords by using truncation (*) or wildcard (e.g., ?, $, !) symbols.
For example, one could search for nurs* to find nurse, nurses, and nursing.
Wildcard searching works similarly: a search for t??th will return results for teeth, tooth, tenth, and so on.