Perhaps you should try some spelling variations:
"support grid integration theories." » "support grid integration theory.", "support grid integration through.", "support grid integration efforts.", "support trade integration theories.", "support _ integration theories.", "support data integration theories.", "support agri integration theories.", "support grant integration theories.", "support group integration theories."
"supply side irrigation system." » "supply side irrigation systems.", "supply side irrigation water.", "supply side irrigation scheme.", "supply scale irrigation system.", "supply under irrigation system.", "supply spate irrigation system."

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• If you are trying to use Boolean operators, they must be ALL CAPS: (("support grid integration theories.") OR ("supply side irrigation system."))~.
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