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."
"supply race immigration policy." » "supply race migration policy.", "supply scale immigration policy.", "supply mass immigration policy.", "supply more immigration policy.", "supply rates immigration policy.", "supply reach immigration policy.", "supply case immigration policy."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("supply race immigration policy.") OR ("support grant integration theories."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"supply race immigration policy.\") OR (\"support grant integration theories.\"))*".
• Removing quotes may allow a broader search: (( supply race immigration policy. ) OR ( support grant integration theories. ))*.