Perhaps you should try some spelling variations:
"supply china immigration policies." » "supply china immigration policy.", "supply china migration policy.", "supply china migration policies.", "supply chinese immigration policies.", "supply china integration policies.", "supply chains immigration policies.", "supply chain immigration policies."
"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."

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

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