Perhaps you should try some spelling variations:
irrigation schemes » irrigation scheme, irrigation systems
innovation theory » innovation through, motivation theory
costs irrigation » systems irrigation, canal irrigation, crop irrigation
case innovation » based innovation, scale innovation, make innovation
supply case » supply cost, supply chain, supply curve

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply case innovation theory. ) OR ( supply costs irrigation schemes. ))~.
• Adding a wildcard symbol may retrieve word variants: (( supply case innovation theory. ) or ( supply costs irrigation schemes. ))*.