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.
Search Tips:
- If you enter more than two keywords, use parentheses to indicate the proper sequence for the database to search them. For example: "(Optics or Optical) and physics."
- Different databases and catalogs may handle Boolean operators differently. Try using the search help page in a database if Boolean operator use does not seem initially intuitive.
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.