To find the most relevant sources during a keyword search, it is often necessary to use multiple keywords, to combine them, and to construct the search in a way the database will understand. This requires the use of Boolean operators: AND, OR, and NOT.
Using AND between your search terms narrows your search, meaning that all terms must appear somewhere in a record. For example: "geometry AND algebra" retrieves sources containing information about the use of algebra in geometry.
If your search retrieves few or no results, you may want to broaden it using the Boolean operator OR. Using OR between your search terms means that at least one of the terms must appear in the record.
The Boolean operator NOT is sometimes incorporated in a search phrase to exclude records containing a certain term. It should be used with caution because it can cause you to unwittingly eliminate relevant sources from your retrieval set.
