Perhaps you should try some spelling variations:
"support strategy integration theories." » "support strategy integration theorems.", "support strategy integrationstheorie 2.", "support strategy integration theory.", "support strategic integration theories.", "support strategy integrating theories.", "support strategic interaction theories.", "supply strategy integration theories."
"export trade integration south." » "export trade integration study.", "export trade integration some.", "export trade integration social.", "export taxes integration south.", "export base integration south.", "export tax integration south."

Try widening your search to All Fields.

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• Performing a fuzzy search may retrieve terms with similar spellings: (("support strategy integration theories.") or ("export trade integration south."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("support strategy integration theories.") OR ("export trade integration south.")).
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