Perhaps you should try some spelling variations:
"supply regional integration theories." » "supply regional integration through.", "supply regional integration efforts.", "supply regional integration reforms.", "support regional integration theories."
"supply chain integration theory." » "supply chain integration through.", "supply chain information theory.", "supply chain integration report.", "supply trade integration theory.", "supply data integration theory.", "supply grid integration theory."

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 theory.") or ("supply regional integration theories."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("supply chain integration theory.") OR ("supply regional integration theories.")).
• Removing quotes may allow a broader search: (( supply chain integration theory. ) or ( supply regional integration theories. )).
• Adding a wildcard symbol may retrieve word variants: (("supply chain integration theory.") or ("supply regional integration theories."))*.