Perhaps you should try some spelling variations:
"supply trade integration theories." » "supply trade integration theory.", "supply trade integration through.", "supply trade integration efforts.", "supply side integration theories.", "supply case integration theories."
"supply change irrigation scheme." » "supply change mitigation scheme.", "supply canal irrigation scheme.", "supply large irrigation scheme.", "supply change irrigation systems.", "supply charges irrigation scheme.", "supply chain irrigation scheme.", "supply chains irrigation scheme."

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: (("supply trade integration theories.") OR ("supply change irrigation scheme."))~.
• Removing quotes may allow a broader search: (( supply trade integration theories. ) or ( supply change irrigation scheme. ))~.
• Adding a wildcard symbol may retrieve word variants: (("supply trade integration theories.") or ("supply change irrigation scheme."))*.