Perhaps you should try some spelling variations:
"improving end performance metrics." » "improving end performance measures.", "improving und performance metrics.", "improving esd performance metrics.", "improving fund performance metrics.", "improving feed performance metrics.", "improving e performance metrics.", "improving eap performance metrics."
"improving urban performance series." » "improving urban performance studies.", "improving urban performance size.", "improving bank performance series.", "improving loan performance series.", "improving human performance series."

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 urban performance series.") OR ("improving end performance metrics."))~.
• Removing quotes may allow a broader search: (( improving urban performance series. ) or ( improving end performance metrics. ))~.
• Adding a wildcard symbol may retrieve word variants: (("improving urban performance series.") or ("improving end performance metrics."))*.