Perhaps you should try some spelling variations:
irrigation scheme » irrigation systems
how irrigation » crop irrigation, from irrigation, high irrigation
eu integration » _ integration, deep integration, data integration
a integration » _ integration, can integration, data integration
supply how » supply shock

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( supply how irrigation scheme. ) or ( supply ((a integration) OR (eu integration)) theory. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply how irrigation scheme. ) OR ( supply ((a integration) OR (eu integration)) theory. ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( supply how irrigation scheme. ) or ( supply ((a integration) OR (eu integration)) theory. ))*".