Perhaps you should try some spelling variations:
"supply grid integration theories." » "supply grid integration theorems.", "supply grid integrationstheorie 2.", "supply grid integration theory.", "supply crowd integration theories.", "supply great integration theories.", "support grid integration theories."
"supply factor immigration policies." » "supply factor immigration policy.", "supply factor migration policy.", "supply factor integration policies.", "supply labor immigration policies.", "supply anti immigration policies.", "supply factors immigration policies.", "supply sector immigration policies."

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: (("supply grid integration theories.") OR ("supply factor immigration policies."))~.
• Removing quotes may allow a broader search: (( supply grid integration theories. ) or ( supply factor immigration policies. ))~.
• Adding a wildcard symbol may retrieve word variants: (("supply grid integration theories.") or ("supply factor immigration policies."))*.