Perhaps you should try some spelling variations:
"supply water integration theory." » "supply water integration through.", "supply water information theory.", "supply water innovation theory.", "supply water integrating theory.", "supply factor integration theory.", "supply filter integration theory."
"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 integration theory."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("support crop irrigation systems.") OR ("supply water integration theory.")).
• Removing quotes may allow a broader search: (( support crop irrigation systems. ) or ( supply water integration theory. )).
• Adding a wildcard symbol may retrieve word variants: (("support crop irrigation systems.") or ("supply water integration theory."))*.