Perhaps you should try some spelling variations:
channels irrigation » change irrigation, canal irrigation, channels information
integral theory » integrated theory, integration theory, integrating theory
supply channels » supply chains
path integral » task integral
supply path » supply data, supply part, supply pt
systems. » system.

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

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