Perhaps you should try some spelling variations:
"supply chain immigration policies." » "supply chain immigration policy.", "supply chain migration policy.", "supply chain integration policies.", "supply mass immigration policies.", "supply anti immigration policies."
"supply data integration theories." » "supply data integration theory.", "supply data integration through.", "supply data integration efforts.", "supply trade integration theories.", "supply _ integration theories.", "supply data integrity theories.", "supply water 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 chain immigration policies.") or ("supply data integration theories."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("supply chain immigration policies.") OR ("supply data integration theories.")).
• Removing quotes may allow a broader search: (( supply chain immigration policies. ) or ( supply data integration theories. )).
• Adding a wildcard symbol may retrieve word variants: (("supply chain immigration policies.") or ("supply data integration theories."))*.