Perhaps you should try some spelling variations:
"policy international migration some." » "policy international cooperation some.", "policy interventions migration some.", "policy intervention migration some.", "policy international migration sowie.", "policy international migration semi.", "policy international migration soft."
"supply trade integration theories." » "supply trade integration theorems.", "supply trade integrationstheorie 2.", "supply trade integration theory.", "supply case 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 trade integration theories.") or ("policy international migration some."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("supply trade integration theories.") OR ("policy international migration some.")).
• Removing quotes may allow a broader search: (( supply trade integration theories. ) or ( policy international migration some. )).
• Adding a wildcard symbol may retrieve word variants: (("supply trade integration theories.") or ("policy international migration some."))*.