Perhaps you should try some spelling variations:
navigation systems » sanitation systems, irrigation system, capitation system
canal irrigation » scale irrigation
data navigation » water navigation, air navigation, data fabrication
supply canal » supply annual, supply rural, supply case
supply data » supply water

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

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