Perhaps you should try some spelling variations:
"improving thermal performance reviews." » "improving thermal performance review.", "improving thermal performance reports.", "improving thermal performance risks.", "improving external performance reviews.", "improving animal performance reviews.", "improving erm performance reviews."
"Improving thermal performance metrics." » "Improving thermal performance measures."

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 thermal performance reviews."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("Improving thermal performance metrics.") OR ("improving thermal performance reviews.")).
• Removing quotes may allow a broader search: (( Improving thermal performance metrics. ) or ( improving thermal performance reviews. )).
• Adding a wildcard symbol may retrieve word variants: (("Improving thermal performance metrics.") or ("improving thermal performance reviews."))*.