Perhaps you should try some spelling variations:
"supply trade integration theories." » "supply trade integration through.", "supply trade integration efforts.", "supply trade integration reforms.", "supply side integration theories.", "supply case integration theories."
"supply school integration theory." » "supply tool integration theory.", "supply social integration theory.", "supply chain integration theory.", "supply school integration through.", "supply school information theory.", "supply school integration report.", "supply shock integration theory.", "supply scheme integration theory.", "survey school 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 trade integration theories.") or ("supply school integration theory."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("supply trade integration theories.") OR ("supply school integration theory.")).
• Removing quotes may allow a broader search: (( supply trade integration theories. ) or ( supply school integration theory. )).
• Adding a wildcard symbol may retrieve word variants: (("supply trade integration theories.") or ("supply school integration theory."))*.