Perhaps you should try some spelling variations:
"improving social performance measures." » "improving school performance measures.", "improving fiscal performance measures.", "improving financial performance measures."
"improving rural performance series." » "improving rural performance studies.", "improving rural performance size.", "improving euract performance series.", "improving larval performance series.", "improving pupil performance series."

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 series.") or ("improving social performance measures."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving rural performance series.") OR ("improving social performance measures.")).
• Removing quotes may allow a broader search: (( improving rural performance series. ) or ( improving social performance measures. )).
• Adding a wildcard symbol may retrieve word variants: (("improving rural performance series.") or ("improving social performance measures."))*.