Perhaps you should try some spelling variations:
"state vectors" » "state vector", "state detectors"
"state reactor" » "stage reactor", "state reaction", "state vector"
"state action" » "state reactions"
"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 action") OR ("state actors"))) OR ((("state reactor") OR ("state vectors")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"state action\") OR (\"state actors\"))) or (((\"state reactor\") or (\"state vectors\"))))".
• Removing quotes may allow a broader search: (((( state action ) OR ( state actors ))) or ((( state reactor ) or ( state vectors )))).
• Adding a wildcard symbol may retrieve word variants: (((("state action") OR ("state actors"))) or ((("state reactor") or ("state vectors"))))*.