Perhaps you should try some spelling variations:
"improving food performance review." » "improving food performance risk.", "improving food performance evidence.", "improving good performance review.", "improving poor performance review.", "improving fund performance review.", "improving land performance review."
"improving basic performance series." » "improving basic performance metrics.", "improving basic performance reviews.", "improving basic performance targets.", "improving based performance series.", "improving bank performance series.", "improving past performance series.", "improving air performance series.", "improve basic performance series.", "improving public 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 basic performance series.") or ("improving food performance review."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving basic performance series.") OR ("improving food performance review.")).
• Removing quotes may allow a broader search: (( improving basic performance series. ) or ( improving food performance review. )).
• Adding a wildcard symbol may retrieve word variants: (("improving basic performance series.") or ("improving food performance review."))*.