Perhaps you should try some spelling variations:
"Improving thermal performance reviews." » "Improving thermal performance review.", "Improving thermal performance reports.", "Improving thermal performance results."
improving thermal » improving external, improving animal, improving erm
"improving human performance risks." » "improving loan performance risks.", "improving chain performance risks.", "improving human performance risk."

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 reviews.") OR ("improving human performance risks."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"Improving thermal performance reviews.\") OR (\"improving human performance risks.\"))*".
• Removing quotes may allow a broader search: (( Improving thermal performance reviews. ) OR ( improving human performance risks. ))*.