Perhaps you should try some spelling variations:
"supply trade integration theories." » "supply trade integration theory.", "supply trade integration through.", "supply trade integration efforts.", "supply side integration theories.", "supply case integration theories."
"support border integration policies." » "support border immigration policies.", "support border international policies.", "support border migration policies.", "support market integration policies.", "support fare integration policies.", "support modal integration policies.", "support worker integration policies.", "support better integration policies."

Try widening your search to All Fields.

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• Performing a fuzzy search may retrieve terms with similar spellings: (("supply trade integration theories.") or ("support border integration policies."))~.
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