Perhaps you should try some spelling variations:
"import duty integration theories." » "import duty integration theory.", "import duty integration efforts.", "import duty integration reforms.", "import data integration theories.", "import south integration theories.", "import deep integration theories.", "import duties integration theories."
"support can integration through." » "support can innovation through.", "support chain integration through.", "support care integration through.", "support urban integration through.", "support bank integration through.", "support a integration through.", "support tax 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 can integration through."))~.
• Removing quotes may allow a broader search: (( import duty integration theories. ) or ( support can integration through. ))~.
• Adding a wildcard symbol may retrieve word variants: (("import duty integration theories.") or ("support can integration through."))*.