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 series." » "improving rural performance metrics.", "improving rural performance reviews.", "improving rural performance targets.", "improving pupil performance series.", "improving thermal performance series.", "improving overall performance series.", "improving urban performance series.", "improving social performance series."

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