Perhaps you should try some spelling variations:
integration schemes » irrigation schemes, integration some, integration theories
ratio conservation » water conservation, basic conservation, aid conservation
chain integration » trade integration, data integration, grid integration
exports ratio » export ratio, export ratios, export rapid

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 chain integration schemes. ) OR ( exports ratio conservation efforts. ))~.
• Adding a wildcard symbol may retrieve word variants: (( supply chain integration schemes. ) or ( exports ratio conservation efforts. ))*.