Perhaps you should try some spelling variations:
irrigation schemes » irrigation scheme, irrigation systems
social integration » global integration, financial integration, regional integration
integration theory » integration through, information theory, innovation theory
grid irrigation » grain irrigation, drip irrigation, gray irrigation
supply grid » supply crowd, supply great, support grid

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 grid irrigation schemes. ) OR ( supply social integration theory. ))~.
• Adding a wildcard symbol may retrieve word variants: (( supply grid irrigation schemes. ) or ( supply social integration theory. ))*.