Perhaps you should try some spelling variations:
"state section" » "states section", "state reaction", "state action"
"state factors" » "states factors", "state actors", "state factor"
"state vector" » "space vector"
"state actor" » "state actors", "state action", "state sector"

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 section") OR ("state vector"))))) OR ("state factors")).
• Removing quotes may allow a broader search: (((( state actor ) or ((( state section ) or ( state vector ))))) or ( state factors )).
• Adding a wildcard symbol may retrieve word variants: (((("state actor") or ((("state section") or ("state vector"))))) or ("state factors"))*.