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

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

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