Perhaps you should try some spelling variations:
"improving overall performance metrics." » "improving average performance metrics.", "improving thermal performance metrics.", "improving governance performance metrics.", "improving overall performance measures.", "improving coverage performance metrics.", "improving federal performance metrics.", "improving neural performance metrics."
"improving rural performance evidence." » "improving euract performance evidence.", "improving larval performance evidence.", "improving pupil performance evidence."

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