Perhaps you should try some spelling variations:
"support grant integration theories." » "support grant integration theory.", "support grant integration through.", "support grant integration efforts.", "support migrant integration theories.", "support trade integration theories.", "support grid integration theories."
"export taxes integration schemes." » "export taxes irrigation schemes.", "export taxes integration some.", "export trade integration schemes.", "export fare integration schemes.", "export care integration schemes.", "exports taxes integration schemes."

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