Most databases have these common -- but powerful -- search features. Using them helps you retrieve more relevant results.
Sometimes you want all forms of the word -- teenager, teenagers, teenaged. Rather than combining with OR, you can use the *.
The asterisk (*) is a powerful feature that can stand in for any number of letters after the root. So anorex* will retrieve anorexia, anorexic, anorexics, etc.
If you want to search on an exact phrase, you can enter it in quotation marks ("anorexia nervosa")
Combine terms using OR and AND (Boolean Operators) for a more focused search. OR for synonyms, AND to add two concepts.