Perhaps you should try some spelling variations:
"supply mass immigration policies." » "supply mass immigration policy.", "supply mass migration policy.", "supply mass migration policies.", "supply _ immigration policies.", "supply case immigration policies.", "supply costs immigration policies.", "supply asset immigration policies."
"supply data integration theory." » "supply data integration through.", "supply data information theory.", "supply data integration report.", "supply trade integration theory.", "supply _ integration theory.", "supply data integrity theory.", "supply water integration theory."

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