using AND -- OR -- AND NOT in your searches
AND - requires both terms to be in each item returned. If one term is contained in the document and the other is not, the item is not included in the resulting list. (Narrows the search)
Example: A search on stock market AND trading includes results contains:
stock market trading; trading on the stock market; and trading on the late afternoon stock market
OR - either term (or both) will be in the returned document. (Broadens the search)
Example: A search on ecology OR pollution includes results contains: documents containing the world ecology (but not pollution) and other documents containing the word pollution (but not ecology) as well as documents with ecology and pollution in either order or number of uses.
NOT or AND NOT - (Dependent upon the coding of the database's search engine)—the first term is searched, and then any records containing the term after the operators are subtracted from the results. (Be careful with use, as the attempt to narrow the search may be too exclusive and eliminate good records)
A search on Mexico AND NOT city includes results contains: New Mexico; the nation of Mexico; US-Mexico trade; but does not return Mexico City