Perhaps you should try some spelling variations:
associate directors » associated vectors, associated sectors, associated receptors
associate director » associated vector
associate editor » associate editors, associate factor, associated vector

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((((associate editor) OR (associate directors))) OR (associate director)).
• Adding a wildcard symbol may retrieve word variants: ((((associate editor) or (associate directors))) or (associate director))*.