Perhaps you should try some spelling variations:
"import trade integration theories." » "import trade integration theorems.", "import trade integrationstheorie 2.", "import trade integration theory.", "export trade integration theories.", "import taxes integration theories.", "import share integration theories."
"import price indexation through." » "import price integration through.", "import price interaction through.", "import price innovation through.", "import price inflation through.", "import price information through.", "import prices indexation through.", "export price indexation through.", "export prices indexation through."

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

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