Once you enter your initial search into a database, you may find you either got too many or too few results.
The best way to broaden a search is to think of other words that might be used to express your components and use OR to group them. For example: the Internet might also be called the Web, the Net, or WWW.
When using "OR" in a complex search, parentheses are used to group the "OR" words together in a set. Like algebra, the computer adds the OR results together, making a big set, before narrowing it to results that contain the word specified by AND.
Example: Are there security practices that can ensure privacy on the Internet?
(Internet OR net OR Web OR WWW) AND privacy AND (security OR encryption OR cryptography)