Perhaps you should try some spelling variations:
"supply sector integration theories." » "supply sector integration theory.", "supply sector integration through.", "supply sector integration efforts.", "supply social integration theories."
"support grid irrigation schemes." » "support grid irrigation scheme.", "support grid irrigation systems.", "support drip irrigation schemes.", "support syria irrigation schemes.", "support crop irrigation schemes.", "support agri irrigation schemes.", "support grant irrigation schemes.", "support group irrigation 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 grid irrigation schemes.") OR ("supply sector integration theories."))~.
• Removing quotes may allow a broader search: (( support grid irrigation schemes. ) or ( supply sector integration theories. ))~.
• Adding a wildcard symbol may retrieve word variants: (("support grid irrigation schemes.") or ("supply sector integration theories."))*.