Perhaps you should try some spelling variations:
irrigation schemes » irrigation scheme, irrigation systems
rural irrigation » murray irrigation, canal irrigation, gray irrigation
covid testing » food testing, load testing, board testing
supply rural » supply curve
grid testing » ground testing, rapid testing, trend testing

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( supply rural irrigation schemes. ) or ( support ((grid testing) OR (covid testing)) services. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply rural irrigation schemes. ) OR ( support ((grid testing) OR (covid testing)) services. )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( supply rural irrigation schemes. ) or ( support ((grid testing) OR (covid testing)) services. ))".
• Adding a wildcard symbol may retrieve word variants: (( supply rural irrigation schemes. ) or ( support ((grid testing) OR (covid testing)) services. ))*.