Perhaps you should try some spelling variations:
"improving company performance series." » "improving country performance series.", "improving company performance studies.", "improving company performance size.", "improve company performance series.", "improving compliance performance series.", "improving community performance series."
"improving human performance review." » "improving human performance risk.", "improving human performance evidence.", "improving loan performance review.", "improving thermal performance review.", "improving chain 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 company performance series.") or ("improving human performance review."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving company performance series.") OR ("improving human performance review.")).
• Removing quotes may allow a broader search: (( improving company performance series. ) or ( improving human performance review. )).
• Adding a wildcard symbol may retrieve word variants: (("improving company performance series.") or ("improving human performance review."))*.