Perhaps you should try some spelling variations:
sector integration » social integration
integration theory » integration through, information theory, integration report
irrigation scheme » irrigation systems
how irrigation » crop irrigation, from irrigation, high irrigation
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 sector integration theory. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply how irrigation scheme. ) OR ( supply sector integration theory. )).
• Adding a wildcard symbol may retrieve word variants: (( supply how irrigation scheme. ) or ( supply sector integration theory. ))*.