Perhaps you should try some spelling variations:
"improving human performance studies." » "improving human performance audits.", "improving human performance audit.", "improving human performance standards.", "improving loan performance studies.", "improving thermal performance studies.", "improving chain performance studies."
"improving rural performance metrics." » "improving rural performance measures.", "improving euract performance metrics.", "improving larval performance metrics.", "improving pupil performance metrics."

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