Perhaps you should try some spelling variations:
"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."
"support state interaction terms." » "support state interactions terms.", "support state intervention terms.", "support face interaction terms.", "support state interaction term.", "support staff interaction terms.", "support strategy interaction terms.", "support estimate interaction terms."

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