Perhaps you should try some spelling variations:
associated receptors » associated factors, associated secretory, activated receptors
associated vector » associated factors, associate director, associated secretory
associate editor » associate editors, associate director, associated factor
associate factor » associated factors, associate director, associate editors

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 (((associated vector) OR (associated receptors))))) OR (associate factor)).
• Adding a wildcard symbol may retrieve word variants: ((((associate editor) or (((associated vector) or (associated receptors))))) or (associate factor))*.