Perhaps you should try some spelling variations:
"improving social performance series." » "improving school performance series.", "improving fiscal performance series.", "improving financial performance series.", "improving social performance metrics.", "improving social performance reviews.", "improving social performance review."
"improving thermal performance series." » "improving thermal performance metrics.", "improving thermal performance reviews.", "improving thermal performance review.", "improving maternal performance series.", "improving rural performance series.", "improving human performance series."

Try widening your search to All Fields.

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

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