Perhaps you should try some spelling variations:
irrigation schemes » irrigation scheme, irrigation systems
graph interaction » group interaction, graph extraction, face interaction
interaction terms » interaction term
chain irrigation » grain irrigation, change irrigation, basin irrigation
supply graph » supply gap, supply growth, supply gas

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