Perhaps you should try some spelling variations:
"import data integration theories." » "import data integration theory.", "import data integration through.", "import data integration efforts.", "import trade integration theories.", "import _ integration theories.", "import data integrity theories.", "import duty integration theories."
"import data integration series." » "import data integrating services.", "import data integration schemes.", "import data integration social.", "import trade integration series.", "import _ integration series.", "import data integrity series.", "import duty integration series."

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 series.") OR ("import data integration theories."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"import data integration series.\") OR (\"import data integration theories.\"))".
• Removing quotes may allow a broader search: (( import data integration series. ) OR ( import data integration theories. )).
• Adding a wildcard symbol may retrieve word variants: (("import data integration series.") OR ("import data integration theories."))*.