Perhaps you should try some spelling variations:
"import taxes integration theories." » "import taxes integration theory.", "import taxes integration through.", "import taxes integration efforts.", "import trade integration theories.", "import fare integration theories.", "import care integration theories.", "export taxes integration theories."
"export policies integrating services." » "export policies reintegration services.", "export countries integrating services.", "export policy integration services.", "export policies integrated services.", "export policies testing services.", "export policies integrating policies.", "import policies integrating services.", "support policies integrating services.", "export prices integrating services."

Try widening your search to All Fields.

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("import taxes integration theories.") or ("export policies integrating services."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("import taxes integration theories.") OR ("export policies integrating services.")).
• Removing quotes may allow a broader search: (( import taxes integration theories. ) or ( export policies integrating services. )).
• Adding a wildcard symbol may retrieve word variants: (("import taxes integration theories.") or ("export policies integrating services."))*.