Perhaps you should try some spelling variations:
"improving thermal performance series." » "improving thermal performance studies.", "improving thermal performance size.", "improving external performance series.", "improving animal performance series.", "improving erm performance series."
"improving loan performance review." » "improving loan performance risk.", "improving loan performance evidence.", "improving local performance review.", "improving land performance review.", "improving lead 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 thermal performance series.") OR ("improving loan performance review."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"improving thermal performance series.\") OR (\"improving loan performance review.\"))".
• Removing quotes may allow a broader search: (( improving thermal performance series. ) OR ( improving loan performance review. )).
• Adding a wildcard symbol may retrieve word variants: (("improving thermal performance series.") OR ("improving loan performance review."))*.