Perhaps you should try some spelling variations:
"support tax integration theories." » "support tax integration theory.", "support tax integration through.", "support tax integration efforts.", "support can integration theories.", "support tax interaction theories.", "support trade integration theories.", "support staff integration theories.", "support state integration theories."
"support a interaction theories." » "support a interaction terms.", "support a interaction term.", "support a integration theory.", "support _ interaction theories.", "support tax interaction theories.", "support _ interactions theories."

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

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