The Complete Researcher by 
A History of Modern Psychology by 
A History of Psychology by 
The Process of Research in Psychology by 
Research Methods in Psychology by 
Selecting and Describing Your Research Instruments by 
Women Theorists of Psychotherapy and Counseling by The Boolean operators AND, OR, and NOT are often used to combine keywords when searching catalogs and databases. These operators can make your search more focused and return more results. But before using the operators, it is necessary to understand how they actually work.
It is helpful to diagram the effects of these operators:
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A search for rock AND roll will locate all records containing both the word "rock" and the word "roll." It will locate items about rock and roll music. It might also locate records that contain both words in a different context, such as "It recommends you roll the rock quickly." |
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A search for rock OR roll will locate all records containing either the word "rock" or the word "roll" -- not necessarily both. It will retrieve items about bakery rolls, tumbling, rocks, music, gemstones, etc. |
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A search for rock NOT roll will locate records containing the word "rock" but NOT the word "roll." It will retrieve items about rocks, gemstones, diamonds, etc. Keep in mind that a search for "rock NOT roll" will return different records than the search "roll NOT rock." |
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: