If you search a catalog or database and receive a large number of results, add a limit or additional keyword in order to retrieve a manageable and relevant number of results to review. At the same time 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 you to limit or expand searches depending on your needs.
For example, a search for environment AND wildlife will return items that contain both "wildlife" and "environment":
environment OR ecology returns items that contain either one of the terms or both:
central america NOT costa rica returns items that talk about the region but do not mention the country Costa Rica:
An important strategy to use when searching for phrases ("political ecology") or titles:
For example, "Biodiversity under threat"
will search for those words in that order, finding the 2011 film about Bengal tigers in Bangladesh.
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 politic* to find poltic, politics, political, politicking, and so on.
Wildcard searches are for differences within words: a search for wom?n will return results for woman, women, and womyn.
When pairing two or more keywords with another keyword, it is important to "nest" the former terms within a larger Boolean search.
For example, (park* OR preserve*) AND (animal* OR wildlife) will return results for the union of the two subject areas.
In Proquest Research Library this search returns results including: Functional Wildlife Parks: The Views of Kenyan Children who Live with Them
Natural Resources Forum 28, 3 (2004): 205-215.