Perhaps you should try some spelling variations:
"state vectors" » "state detectors", "space vectors"
"state sector" » "estate sector", "state section", "state sensor"
"state vector" » "space vector"
"state actor" » "state action", "state after"
"state actors" » "state actions", "state afters", "state factors"
"state acts" » "state tracts", "late acts", "state action"

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 actor") OR ("state acts"))) OR ((((("state sector") OR ("state vectors"))) OR ("state vector"))))) OR ("state actors"))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((((\"state actor\") OR (\"state acts\"))) or (((((\"state sector\") or (\"state vectors\"))) or (\"state vector\"))))) or (\"state actors\"))*".
• Removing quotes may allow a broader search: (((((( state actor ) OR ( state acts ))) or ((((( state sector ) or ( state vectors ))) or ( state vector ))))) or ( state actors ))*.