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 review."
"improving poor performance series." » "improving poor performance metrics.", "improving poor performance reviews.", "improving poor performance targets.", "improving export performance series.", "improving sector performance series.", "improving _ performance series.", "improving power performance series.", "improving food performance series.", "improving indoor performance series."

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