Perhaps you should try some spelling variations:
"improving thermal performance metrics." » "improving thermal performance contracts.", "improving thermal performance measures.", "improving thermal performance contract.", "improving maternal performance metrics.", "improving human performance metrics.", "improving mental performance metrics."
"improving rural performance reviews." » "improving rural performance review.", "improving rural performance reports.", "improving rural performance risks.", "improving pupil performance reviews.", "improving overall performance reviews.", "improving fiscal performance reviews.", "improving urban performance reviews.", "improving social performance reviews."

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 rural performance reviews."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving thermal performance metrics.") OR ("improving rural performance reviews.")).
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