Perhaps you should try some spelling variations:
irrigation schemes » irrigation scheme, irrigation systems
integration theory » integration through, information theory, innovation theory
crop irrigation » drip irrigation, scale irrigation, canal irrigation
supply crowd » supply growth, supply cost, supply from
supply crop » supply from, supply europe, supply curve

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

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