​"AND"  helps narrow the search: 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.​​

"OR" broadens the search: Either term (or both) will be in the returned document.​

"NOT" focuses the search: The first term is searched, then any records containing the term after the operators are subtracted from the results.​

( ) or " " enclose search strategies that will customize your results.