More complicated searches can be constructed by combining a larger number of keywords with the Boolean operators AND, NOT, and OR. This is known as BOOLEAN SEARCHING
Parentheses () must be used to highlight the relationships between the terms or the database will impose a different emphasis.
Both term A and term B must occur.
Either term A or term B must occur.
Term A must occur, but term B must not.
Some databases use different conventions for this, for example CDS/ISIS uses (*), (+) and (^). Always check the relevant database documentation or help screens for information
The complete search statement for the example on the previous page would be: