Perhaps you should try some spelling variations:
"improving urban performance metrics." » "improving urban performance measures.", "improving bank performance metrics.", "improving loan performance metrics.", "improving human performance metrics."
"improved plant performance evidence." » "improved port performance evidence.", "improved court performance evidence.", "improved land performance evidence.", "improves implant performance evidence.", "improved infant performance evidence."

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