Library Databases Guide (Electronic Resources)

The Boolean operators AND, OR, and NOT are often used to combine keywords when searching research databases. Use of these operators can make your search more focused, thus yielding more precise search results. But before using the operators, it's necessary to understand how they actually work.

Boolean Searching

Keep in mind that the connectors AND and NOT generally limit your search (decreases the number of hits) and the connector OR expands it (increases the number of hits). So the following strategies naturally follow:

• If you are retrieving too many records on your topic, try adding another search term with the connector AND.
• If you are retrieving too many records on an unrelated topic, try eliminating a word with the connector NOT
• If you are retrieving too few records on your topic, try adding another search term with the connector OR.

Advanced Search Methods: Truncation / Wildcards / Controlled Vocabulary

Truncation

Truncation allows you to search the "root" form of a word with all its different endings by adding a symbol to the end of a word. Example: typing in bank* will retrieve results with these words: bank, banks, banking, bankers, bankruptcy The most common truncation symbol is the asterisk * but databases vary. Check the database Help section to find the correct truncation symbol. Example: bank* bank! bank# bank? See the sample search below for results using "bank*" in a Discovery search.