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 trade integration theories.", "support data integration theories.", "support a integration theories.", "support staff integration theories.", "support state integration theories."
"support tax interaction theories." » "support tax interaction terms.", "support tax interaction term.", "support tax integration theory.", "support trade interaction theories.", "support face interaction theories.", "support time interaction theories.", "support a interaction theories.", "support staff interaction theories.", "support state interaction 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 tax interaction theories."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"support tax integration theories.\") OR (\"support tax interaction theories.\"))".
• Removing quotes may allow a broader search: (( support tax integration theories. ) OR ( support tax interaction theories. )).
• Adding a wildcard symbol may retrieve word variants: (("support tax integration theories.") OR ("support tax interaction theories."))*.