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 plant performance series." » "improving plant performance metrics.", "improving plant performance reviews.", "improving plant performance targets.", "improving bank performance series.", "improving loan performance series.", "improving port performance series.", "improving land performance series.", "improving laws performance series.", "improving payment 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 plant performance series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving human performance review.") OR ("improving plant performance series."))*.
• Removing quotes may allow a broader search: (( improving human performance review. ) or ( improving plant performance series. ))*.