More about NOT

This Venn diagram illustrates the use of the Boolean operator NOT -- the colored area represents the result of the Boolean operation.

In general, NOT finds records that contain one term but not the other. My example is using mixed Boolean operators. I'm searching for AIDS (the disease concept) but I want to make sure that I don't pick up records that have to do with either 'visual aids' or 'hearing aids'.

And here's how the search strategy would look using Ovid MEDLINE:

1. aids
2. hearing
3. visual
4. 1 not (2 or 3)

FYI:

• In this search, I did not use MeSH terms; instead, I did textword searches.
• Caution! Be careful how you use NOT. You could potentially exclude relevant articles.