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."
"improving thermal performance series." » "improving thermal performance studies.", "improving thermal performance size.", "improving external performance series.", "improving animal performance series.", "improving erm 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 urban performance metrics.") or ("improving thermal performance series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving urban performance metrics.") OR ("improving thermal performance series."))*.
• Removing quotes may allow a broader search: (( improving urban performance metrics. ) or ( improving thermal performance series. ))*.