Perhaps you should try some spelling variations:
"improving poor performance review." » "improving poor performance risk.", "improving poor performance evidence.", "improving sector performance review.", "improving power performance review.", "improving food performance review.", "improving peer performance review."
"improving human performance contracts." » "improving loan performance contracts.", "improving thermal performance contracts.", "improving chain performance contracts."

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