Perhaps you should try some spelling variations:
"support policy integration theories." » "support policy integration theorems.", "support policy integrationstheorie 2.", "support policy integration theory.", "support political integration theories.", "support policy international theories.", "support policy intervention theories.", "support policies integration theories.", "import policy integration theories."
"support water irrigation scheme." » "support water irrigation systems.", "support scale irrigation scheme.", "support canal irrigation scheme.", "support farm irrigation scheme.", "support chapter irrigation scheme.", "support greater irrigation scheme.", "support better 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: (("support water irrigation scheme.") or ("support policy integration theories."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("support water irrigation scheme.") OR ("support policy integration theories.")).
• Removing quotes may allow a broader search: (( support water irrigation scheme. ) or ( support policy integration theories. )).
• Adding a wildcard symbol may retrieve word variants: (("support water irrigation scheme.") or ("support policy integration theories."))*.