Boolean Operators (AND, OR, etc.) are ways to combine your terms to get the results you want. A couple reminders:
- Use AND if you want to search for all terms (e.g., exercise AND hypertension). Using AND will always narrow your search (produce fewer hits) because it's looking for the occurrence of all terms together (exercise and hypertension) in the search.
- Use OR if you want to search one term or another but not necessarily both, (e.g., blood pressure OR hypertension). Using OR will always broaden your search (produce more hits) because it's looking for the occurrence of either term, not both together.