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."

Try widening your search to All Fields.

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• 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.")).
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