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

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

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