Perhaps you should try some spelling variations:
"improving human performance review." » "improving human performance risk.", "improving human performance evidence.", "improving loan performance review.", "improving thermal performance review.", "improving company performance review.", "improving urban performance review."
"improving rural performance risks." » "improving pupil performance risks.", "improving thermal performance risks.", "improving overall performance risks.", "improving rural performance risk.", "improving rural performance issues.", "improving rural performance based.", "improving urban performance risks.", "improving social performance risks."

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