Perhaps you should try some spelling variations:
"support policy integration theories." » "support policy integration theory.", "support policy integration through.", "support policy integration efforts.", "support policy intervention theories.", "support social integration theories.", "support policy interventions theories.", "support policies integration theories.", "import policy integration theories."
"support water irrigation schemes." » "support water irrigation scheme.", "support water irrigation systems.", "support water sanitation schemes.", "support scale irrigation schemes.", "support canal irrigation schemes.", "support better irrigation schemes.", "support what's irrigation schemes.", "support worker 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 water irrigation schemes.") OR ("support policy integration theories."))~.
• Removing quotes may allow a broader search: (( support water irrigation schemes. ) or ( support policy integration theories. ))~.
• Adding a wildcard symbol may retrieve word variants: (("support water irrigation schemes.") or ("support policy integration theories."))*.