Perhaps you should try some spelling variations:
"support grant integration theories." » "support grant integration theorems.", "support grant integrationstheorie 2.", "support grant integration theory.", "support migrant integration theories.", "support migrants integration theories.", "support statt integration theories."
"support project immigration policies." » "support project immigration policy.", "support project migration policy.", "support project integration policies.", "support projekt migration policies.", "support project initiation 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: (("support grant integration theories.") OR ("support project immigration policies."))~.
• Removing quotes may allow a broader search: (( support grant integration theories. ) or ( support project immigration policies. ))~.
• Adding a wildcard symbol may retrieve word variants: (("support grant integration theories.") or ("support project immigration policies."))*.