Perhaps you should try some spelling variations:
associated secretory » associated factors, associated operators
associated vector » associated factors, associate director, associated infection
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 (((associate factor) OR (associated secretory)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((associate editor) OR (associated vector))) or (((associate factor) or (associated secretory))))".
• Adding a wildcard symbol may retrieve word variants: ((((associate editor) OR (associated vector))) or (((associate factor) or (associated secretory))))*.