Perhaps you should try some spelling variations:
"supply chains irrigation schemes." » "supply chains irrigation scheme.", "supply chains irrigation systems.", "supply change irrigation schemes.", "supply grain irrigation schemes.", "supply canal irrigation schemes.", "supply chain irrigation schemes."
"supply grid conservation efforts." » "supply aid conservation efforts.", "supply good conservation efforts.", "supply grass conservation efforts.", "supply crowd conservation efforts.", "supply great conservation efforts.", "support grid conservation efforts."

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 chains irrigation schemes.") OR ("supply grid conservation efforts."))~.
• Removing quotes may allow a broader search: (( supply chains irrigation schemes. ) or ( supply grid conservation efforts. ))~.
• Adding a wildcard symbol may retrieve word variants: (("supply chains irrigation schemes.") or ("supply grid conservation efforts."))*.