Perhaps you should try some spelling variations:
surface irrigation » scale irrigation
irrigation schemes » irrigation scheme, irrigation systems
integration some » integration south, integration soziale, integration social
supply surface » supply service, upper surface
export trade » export taxes, export base, export tax

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 schemes. ) or ( export trade integration some. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply surface irrigation schemes. ) OR ( export trade integration some. )).
• Adding a wildcard symbol may retrieve word variants: (( supply surface irrigation schemes. ) or ( export trade integration some. ))*.