Perhaps you should try some spelling variations:
integration efforts » international efforts, conservation efforts
surface irrigation » scale irrigation
irrigation system » irrigation systems, irrigation water, irrigation scheme
supply surface » supply service
support trade » export trade, support grant, import trade

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( supply surface irrigation system. ) or ( support trade integration efforts. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply surface irrigation system. ) OR ( support trade integration efforts. )).
• Adding a wildcard symbol may retrieve word variants: (( supply surface irrigation system. ) or ( support trade integration efforts. ))*.