Perhaps you should try some spelling variations:
"supply sector integration theories." » "supply sector integration theorems.", "supply sector integrationstheorie 2.", "supply sector integration theory."
"support surge irrigation schemes." » "support surge irrigation scheme.", "support surge irrigation systems.", "support large irrigation schemes.", "support surface irrigation schemes.", "support scale irrigation schemes.", "support stage irrigation schemes.", "support since irrigation schemes.", "import surge 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 surge irrigation schemes.") OR ("supply sector integration theories."))~.
• Removing quotes may allow a broader search: (( support surge irrigation schemes. ) or ( supply sector integration theories. ))~.
• Adding a wildcard symbol may retrieve word variants: (("support surge irrigation schemes.") or ("supply sector integration theories."))*.