Perhaps you should try some spelling variations:
"export prices integrating services." » "export prices integrated services.", "export prices testing services.", "export prices integrating policies.", "export policies integrating services.", "export prices international services.", "export services integration services.", "import prices integrating services."
"import taxes integration theory." » "import taxes integration through.", "import taxes information theory.", "import taxes integration report.", "import trade integration theory.", "import fare integration theory.", "import care integration theory.", "export taxes integration theory."

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