Perhaps you should try some spelling variations:
"supply shadow immigration policies." » "supply shadow immigration policy.", "supply shadow migration policy.", "supply labor immigration policies.", "supply scale immigration policies."
"support migrant integration theories." » "support migrant integration theorems.", "support migrant integrationstheorie 2.", "support migrant integration theory.", "support market integration theories.", "support migrants integration theories.", "support grant integration theories.", "supporting migrants 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 shadow immigration policies.") or ("support migrant integration theories."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("supply shadow immigration policies.") OR ("support migrant integration theories."))*.
• Removing quotes may allow a broader search: (( supply shadow immigration policies. ) or ( support migrant integration theories. ))*.