Perhaps you should try some spelling variations:
"improving human performance reviews." » "improving human performance reports.", "improving human performance risks.", "improving human performance results.", "improving human performance evidences.", "improving loan performance reviews.", "improving thermal performance reviews.", "improving chain performance reviews."
"improving rural performance review." » "improving rural performance risk.", "improving rural performance evidence.", "improving euract performance review.", "improving larval performance review.", "improving pupil performance review."

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 reviews.") OR ("improving rural performance review."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"improving human performance reviews.\") OR (\"improving rural performance review.\"))".
• Removing quotes may allow a broader search: (( improving human performance reviews. ) OR ( improving rural performance review. )).
• Adding a wildcard symbol may retrieve word variants: (("improving human performance reviews.") OR ("improving rural performance review."))*.