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

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