Perhaps you should try some spelling variations:
"export trade integration theories." » "export trade integration theorems.", "export trade integrationstheorie 2.", "export trade integration theory.", "export taxes integration theories.", "export base integration theories.", "export tax integration theories."
"support groups integrating culture." » "support groups integrating multiple.", "support gaps integrating culture.", "support process integrating culture.", "support through integrating culture.", "support group integrating culture."

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: (("export trade integration theories.") OR ("support groups integrating culture."))~.
• Removing quotes may allow a broader search: (( export trade integration theories. ) or ( support groups integrating culture. ))~.
• Adding a wildcard symbol may retrieve word variants: (("export trade integration theories.") or ("support groups integrating culture."))*.