Perhaps you should try some spelling variations:
"improving company performance series." » "improving country performance series.", "improving company performance studies.", "improving company performance size.", "improve company performance series.", "improving compliance performance series.", "improving community performance series."
"improving thermal performance evidence." » "improving external performance evidence.", "improving animal performance evidence.", "improving erm performance evidence."

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