A very broad search brings in a bazillion results!
Adding another search term focuses the results when you use the AND connecter.
The more search terms you add, the fewer results.
To expand the results, de-select an irrelevant area of study from the list of limiters.
(Not pictured) To further narrow the results, select other limiters on the list offered (below the limiters shown), such as "Peer Reviewed"
(Note: When looking for book results, de-select "Peer Reviewed.")