Perhaps you should try some spelling variations:
"export trade integration theories." » "export trade integration theory.", "export trade integration through.", "export trade integration efforts.", "export share integration theories.", "export taxes integration theories.", "export price integration theories."
"support group integration series." » "support group integrating services.", "support group integration schemes.", "support group integration social.", "support grid integration series.", "support run integration series.", "support through integration series.", "support from integration series.", "support grant integration series."

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