Perhaps you should try some spelling variations:
"supply national immigration policies." » "supply national immigration policy.", "supply national migration policy.", "supply national integration policies.", "supply national irrigation policies.", "supply national immunization policies.", "support national immigration policies.", "supply international immigration policies."
"supply trade integration theories." » "supply trade integration theorems.", "supply trade integrationstheorie 2.", "supply trade integration theory.", "supply case integration theories."

Try widening your search to All Fields.

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

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