Perhaps you should try some spelling variations:
"improving co performance reviews." » "improving co performance review.", "improving co performance reports.", "improving co performance risks.", "improving ceo performance reviews.", "improving do performance reviews.", "improving core performance reviews.", "improving eco performance reviews.", "improving crop performance reviews.", "improving ict performance reviews."
"improving food performance contracts." » "improving good performance contracts.", "improving fund performance contracts.", "improving bond performance contracts."

You may be able to get more results by adjusting your search query.

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