Boolean Logic (continued)
- Boolean operators AND, OR and NOT must be entered in UPPERCASE.
- AND is the default operator used in PubMed. If you do not include Boolean operators in your search, PubMed will automatically use AND between terms.
- PubMed processes Boolean connectors left-to-right.
- You can change the order of processing by nesting an individual concept in parentheses. The terms inside the parentheses will be processed as a unit and then incorporated into the overall strategy. [Show Me]