Perhaps you should try some spelling variations:
"supply social integration theories." » "supply social integration theorems.", "supply social integrationstheorie 2.", "supply social integration theory.", "supply global integration theories.", "supply financial integration theories.", "supply regional integration theories."
"export trade integration schemes." » "export trade integration schengen.", "export trade irrigation schemes.", "export trade integration regimes.", "export taxes integration schemes.", "export base integration schemes.", "export tax integration schemes."

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("export trade integration schemes.") or ("supply social integration theories."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("export trade integration schemes.") OR ("supply social integration theories.")).
• Removing quotes may allow a broader search: (( export trade integration schemes. ) or ( supply social integration theories. )).
• Adding a wildcard symbol may retrieve word variants: (("export trade integration schemes.") or ("supply social integration theories."))*.