Perhaps you should try some spelling variations:
"supply water integrating theories." » "supply water integration theories.", "supply water integrating theory.", "supply water interpolating theories.", "supply lever integrating theories.", "supply water integrated theories.", "supply patterns integrating theories."
"support crop irrigation systems." » "support drip irrigation systems.", "support scale irrigation systems.", "support canal irrigation systems.", "support crops irrigation systems.", "support cross irrigation systems.", "support across irrigation systems.", "support crop irrigation system."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("support crop irrigation systems.") or ("supply water integrating theories."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("support crop irrigation systems.") OR ("supply water integrating theories.")).
• Removing quotes may allow a broader search: (( support crop irrigation systems. ) or ( supply water integrating theories. )).
• Adding a wildcard symbol may retrieve word variants: (("support crop irrigation systems.") or ("supply water integrating theories."))*.