Perhaps you should try some spelling variations:
"improving rural performance studies." » "improving rural performance audits.", "improving rural performance audit.", "improving rural performance standards.", "improving euract performance studies.", "improving larval performance studies.", "improving pupil performance studies."
"improving financial performance series." » "improving financial performance size."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("improving rural performance studies.") or ("improving financial performance series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving rural performance studies.") OR ("improving financial performance series."))*.
• Removing quotes may allow a broader search: (( improving rural performance studies. ) or ( improving financial performance series. ))*.