Perhaps you should try some spelling variations:
"support grant integration theories." » "support grant integration theorems.", "support grant integrationstheorie 2.", "support grant integration theory.", "support migrant integration theories.", "support migrants integration theories.", "support statt integration theories."
"supply case irrigation scheme." » "supply case irrigation systems.", "supply scale irrigation scheme.", "supply use irrigation scheme.", "supply change irrigation scheme.", "supply cost irrigation scheme.", "supply chain irrigation scheme.", "supply curve irrigation scheme."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("supply case irrigation scheme.") or ("support grant integration theories."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("supply case irrigation scheme.") OR ("support grant integration theories.")).
• Removing quotes may allow a broader search: (( supply case irrigation scheme. ) or ( support grant integration theories. )).
• Adding a wildcard symbol may retrieve word variants: (("supply case irrigation scheme.") or ("support grant integration theories."))*.