Perhaps you should try some spelling variations:
"supply cost integration theory." » "supply cost integration through.", "supply cost information theory.", "supply cost innovation theory.", "supply post integration theory.", "supply test integration theory.", "supply about integration theory.", "supply costs integration theory."
"supply furrow irrigation system." » "supply farm irrigation system.", "supply crop irrigation system.", "supply flood irrigation system.", "supply furrow irrigation systems.", "supply furrow irrigation water.", "supply furrow irrigation scheme.", "supply from irrigation system."

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (("supply cost integration theory.") OR ("supply furrow irrigation system."))~.
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