Perhaps you should try some spelling variations:
"support a integration theory." » "support a integration through.", "support a information theory.", "support a innovation theory.", "support 3 integration theory.", "support 2 integration theory.", "support 4 integration theory.", "support _ integration theory."
"support water irrigation schemes." » "support water irrigation scheme.", "support water irrigation systems.", "support scale irrigation schemes.", "support canal irrigation schemes.", "support farm irrigation schemes.", "support chapter irrigation schemes.", "support greater irrigation schemes.", "support better irrigation schemes."

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 schemes.") or ("support a integration theory."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("support water irrigation schemes.") OR ("support a integration theory.")).
• Removing quotes may allow a broader search: (( support water irrigation schemes. ) or ( support a integration theory. )).
• Adding a wildcard symbol may retrieve word variants: (("support water irrigation schemes.") or ("support a integration theory."))*.