Perhaps you should try some spelling variations:
"support trade integration theories." » "support trade integration theory.", "support trade integration through.", "support trade integration efforts.", "export trade integration theories.", "import trade integration theories.", "support price integration theories."
"support grant integration schemes." » "support grant irrigation schemes.", "support grant integration some.", "support migrant integration schemes.", "support grid integration schemes.", "support urban integration schemes."

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

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