Perhaps you should try some spelling variations:
"improving poor performance studies." » "improving poor performance audits.", "improving poor performance audit.", "improving poor performance standards.", "improving sector performance studies.", "improving power performance studies.", "improving food performance studies.", "improving peer performance studies."
"improve good performance review." » "improve good performance risk.", "improve good performance evidence.", "improve fund performance review.", "improve court performance review.", "improve 2 performance review.", "improve food performance review.", "improved food performance review.", "improve our performance review."

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