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 series." » "support market integration series.", "support migrant integration services.", "support migrant interaction series.", "support migrant integration server.", "support migrants integration series.", "support grant integration series.", "supporting migrants integration series."

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 chain integration theories.") OR ("support migrant integration series."))~.
• Removing quotes may allow a broader search: (( supply chain integration theories. ) or ( support migrant integration series. ))~.
• Adding a wildcard symbol may retrieve word variants: (("supply chain integration theories.") or ("support migrant integration series."))*.