Perhaps you should try some spelling variations:
"state vectors" » "state detectors", "space vectors"
"state action" » "state reactions"
"state sector" » "estate sector", "state section", "space sector"
"state vector" » "space vector"
"state actors" » "state factors"

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: (((((("state vectors") OR ("state action"))) OR ((("state sector") OR ("state vector"))))) OR ("state actors")).
• Removing quotes may allow a broader search: (((((( state vectors ) or ( state action ))) or ((( state sector ) or ( state vector ))))) or ( state actors )).
• Adding a wildcard symbol may retrieve word variants: (((((("state vectors") or ("state action"))) or ((("state sector") or ("state vector"))))) or ("state actors"))*.