Perhaps you should try some spelling variations:
"improving academic performance measures." » "improving economic performance measures.", "improving trade performance measures."
"improving based performance based." » "improving bank performance based.", "improving care performance based.", "improving board performance based.", "improving basic performance based.", "improving shared performance based.", "improving water performance based."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("improving academic performance measures.") or ("improving based performance based."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving academic performance measures.") OR ("improving based performance based.")).
• Removing quotes may allow a broader search: (( improving academic performance measures. ) or ( improving based performance based. )).
• Adding a wildcard symbol may retrieve word variants: (("improving academic performance measures.") or ("improving based performance based."))*.