Perhaps you should try some spelling variations:
"improving do performance metrics." » "improving do performance measures.", "improving di performance metrics.", "improving 2 performance metrics.", "improving 3 performance metrics.", "improving co performance metrics.", "improving eco performance metrics.", "improving pro performance metrics."
"improving poor performance series." » "improving poor performance studies.", "improving poor performance size.", "improving sector performance series.", "improving power performance series.", "improving food performance series.", "improving peer performance series."

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