Perhaps you should try some spelling variations:
"import data integration theories." » "import data integration through.", "import data integration efforts.", "import data integration reforms.", "import trade integration theories.", "import _ integration theories.", "import data integrity theories.", "import duty integration theories."
"import data integration theory." » "import data integration through.", "import data information theory.", "import data integration report.", "import trade integration theory.", "import _ integration theory.", "import data integrity theory.", "import duty 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 data integration theory.") or ("import data integration theories."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("import data integration theory.") OR ("import data integration theories.")).
• Removing quotes may allow a broader search: (( import data integration theory. ) or ( import data integration theories. )).
• Adding a wildcard symbol may retrieve word variants: (("import data integration theory.") or ("import data integration theories."))*.