Perhaps you should try some spelling variations:
"supply chain integration theories." » "supply chain integration theorems.", "supply chain integrationstheorie 2.", "supply chain integration theory."
"support migrant integration services." » "support migrant integrating services.", "support migrant integrated services.", "support migrant insemination services.", "support market integration services.", "support migrants integration services.", "support grant integration services.", "supporting migrants integration services."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("supply chain integration theories.") OR ("support migrant integration services."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"supply chain integration theories.\") OR (\"support migrant integration services.\"))".
• Removing quotes may allow a broader search: (( supply chain integration theories. ) OR ( support migrant integration services. )).
• Adding a wildcard symbol may retrieve word variants: (("supply chain integration theories.") OR ("support migrant integration services."))*.