Perhaps you should try some spelling variations:
"import duty integration theories." » "import duty integration theorems.", "import duty integrationstheorie 2.", "import duty integration theory.", "import dutch integration theories.", "import data integration theories.", "import why integration theories.", "import duties integration theories."
"support urban integration through." » "support urban innovation through.", "support european integration through.", "support urban migration through.", "support chain integration through.", "support carbon integration through.", "report urban integration through.", "supply urban integration through."

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: (("import duty integration theories.") OR ("support urban integration through."))~.
• Removing quotes may allow a broader search: (( import duty integration theories. ) or ( support urban integration through. ))~.
• Adding a wildcard symbol may retrieve word variants: (("import duty integration theories.") or ("support urban integration through."))*.