Perhaps you should try some spelling variations:
integration theories » integration theory, integration through, integration efforts
price integration » service integration, policy integration, trade integration
irrigation scheme » irrigation systems
water irrigation » water sanitation, scale irrigation, canal irrigation
import price » import prices, export price, export prices

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: (( import price integration theories. ) OR ( supply water irrigation scheme. ))~.
• Adding a wildcard symbol may retrieve word variants: (( import price integration theories. ) or ( supply water irrigation scheme. ))*.