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 bank performance series." » "improving bank performance studies.", "improving bank performance size.", "improving urban performance series.", "improving basic performance series.", "improving brain performance series."

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 bank performance series."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"improving thermal performance series.\") OR (\"improving bank performance series.\"))".
• Removing quotes may allow a broader search: (( improving thermal performance series. ) OR ( improving bank performance series. )).
• Adding a wildcard symbol may retrieve word variants: (("improving thermal performance series.") OR ("improving bank performance series."))*.