Perhaps you should try some spelling variations:
"export data integration theories." » "export data integration theory.", "export data integration through.", "export data integration efforts.", "export trade integration theories.", "export _ integration theories.", "export data integrity theories.", "export day integration theories.", "export ratio integration theories."
"import data irrigation schemes." » "import data irrigation scheme.", "import data irrigation systems.", "import canal irrigation schemes.", "import water irrigation schemes.", "import spate irrigation schemes.", "import duty irrigation schemes."

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