Perhaps you should try some spelling variations:
"supply grid integration theories." » "supply grid integration theory.", "supply grid integration through.", "supply grid integration efforts.", "supply trade integration theories.", "supply _ integration theories.", "supply data integration theories.", "supply crowd integration theories.", "support grid integration theories."
"supply from immigration policies." » "supply from immigration policy.", "supply from migration policy.", "supply from migration policies.", "supply from imitation policies.", "supply _ immigration policies.", "support from immigration policies."

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("supply grid integration theories.") or ("supply from immigration policies."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("supply grid integration theories.") OR ("supply from immigration policies."))*.
• Removing quotes may allow a broader search: (( supply grid integration theories. ) or ( supply from immigration policies. ))*.