Perhaps you should try some spelling variations:
"improving national performance targets." » "improving regional performance targets.", "improving operational performance targets.", "improving educational performance targets.", "improving maternal performance targets.", "improving natural performance targets.", "improve national performance targets."
"improving thermal performance metrics." » "improving thermal performance measures.", "improving external performance metrics.", "improving animal performance metrics.", "improving erm performance metrics."

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("improving thermal performance metrics.") or ("improving national performance targets."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving thermal performance metrics.") OR ("improving national performance targets."))*.
• Removing quotes may allow a broader search: (( improving thermal performance metrics. ) or ( improving national performance targets. ))*.