Perhaps you should try some spelling variations:
"improving poor performance metrics." » "improving poor performance measures.", "improving sector performance metrics.", "improving power performance metrics.", "improving food performance metrics.", "improving peer performance metrics."
"improving trade performance series." » "improving trade performance studies.", "improving trade performance size.", "improving care performance series.", "improving tax performance series.", "improving teacher 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 trade performance series.") or ("improving poor performance metrics."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving trade performance series.") OR ("improving poor performance metrics."))*.
• Removing quotes may allow a broader search: (( improving trade performance series. ) or ( improving poor performance metrics. ))*.