To find the most relevant sources during a keyword search, it is often necessary
to use multiple keywords and 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: "Optics AND Physics"
retrieves sources containing information about the field of Optics within Physics.
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. For example, the search "Physics NOT Optics" will retrieve topics in physics not related to optics. It should be used with caution because it can cause you to unwittingly eliminate relevant sources from your retrieval set.
