Boolean searching is a technique which uses the principles of symbolic logic introduced by UK mathematician George Boole to help researchers expand or restrict a search by using three language operators, AND, OR, NOT. The operator AND narrows a search. The operator OR expands a search. The operator NOT also narrows a search but can sometimes result in eliminating relevant items and should be used with caution. Most research databases supply a search template with boxes which can be connected by one of the three operators to help you organize your search logic.
You can even use search operators in a Google search http://www.google.com/advanced_search
Venn diagrams provide a pictorial representation of these concepts.
Use AND to search for specific terms, usually retrieves fewer results.
Use OR to search for synonyms or variations of terms, usually retrieves more search results.
beaver AND duck = platypus
To expand your search results, consider searching in general and multidisciplinary databases or search for multiple databases with the same platform.
For example, when you search the Social Work Abstracts database, click on the "Choose Databases" link. This will allow us to search all or selected EBSCOhost databases in tandem (see image). Duplicate records are usually removed. The drawback is that subject headings cannot be used when using this tactic.
If you found an "ideal" article, here are two ways to expand your search Web of Science database
Retrieve the "ideal" article on the Web of Science database or in Google Scholar. Then, examine the record for articles that cite your "ideal" article (that is, click on the "Times Cited" articles on Web of Science).
This citing reference searching is a quick and efficient way to find more related and newer articles.
Look at the references (e.g. "Cited References" or bibliography of the article) in your "ideal" article as these articles may be related in some fashion; and will be older than your "ideal" article.