Perhaps you should try some spelling variations:
irrigation scheme » irrigation systems
chain irrigation » grain irrigation, change irrigation, basin irrigation
internal system » internal systems
aa internal » data internal, ayu internal, ida internal
supply aa » supply a, supply asia, supply data

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( supply chain irrigation scheme. ) or ( supply aa internal system. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply chain irrigation scheme. ) OR ( supply aa internal system. )).
• Adding a wildcard symbol may retrieve word variants: (( supply chain irrigation scheme. ) or ( supply aa internal system. ))*.