Perhaps you should try some spelling variations:
"support vertical integration theories." » "support regional integration theories.", "support vertical integration theory.", "support vertical integration through.", "support vertical integration efforts.", "support technical integration theories.", "airports vertical integration theories.", "support services integration theories."
"support fare integration series." » "support fare integrating services.", "support fare integration schemes.", "support fare integration social.", "support market integration series.", "support trade integration series.", "support data integration series.", "support falls integration series.", "support state integration series."

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

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