Perhaps you should try some spelling variations:
"improving thermal performance risk." » "improving maternal performance risk.", "improving rural performance risk.", "improving human performance risk.", "improving thermal performance size.", "improving thermal performance _.", "improving thermal performance data."
"improving poor performance based." » "improving poor performance measures.", "improving export performance based.", "improving sector performance based.", "improving _ performance based.", "improving power performance based.", "improving food performance based.", "improving indoor performance based."

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