Perhaps you should try some spelling variations:
"supply shallow integration countries." » "supply shallow integrating countries.", "supply shallow immigration countries.", "supply shallow emigration countries."
"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."

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