Perhaps you should try some spelling variations:
"improving rural performance metrics." » "improving rural performance measures.", "improving euract performance metrics.", "improving larval performance metrics.", "improving pupil performance metrics."
"improving human performance series." » "improving human performance studies.", "improving human performance size.", "improving loan performance series.", "improving thermal performance series.", "improving chain 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 human performance series.") or ("improving rural performance metrics."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving human performance series.") OR ("improving rural performance metrics."))*.
• Removing quotes may allow a broader search: (( improving human performance series. ) or ( improving rural performance metrics. ))*.