Perhaps you should try some spelling variations:
"improving annual performance series." » "improving fiscal performance series.", "improving social performance series.", "improving financial performance series.", "improving annual performance studies.", "improving annual performance size.", "improving animal performance series.", "improving sexual performance series.", "improving antenatal performance series."
"improving firm performance evidence." » "improving firms performance evidence.", "improving air 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 firm performance evidence.") or ("improving annual performance series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving firm performance evidence.") OR ("improving annual performance series.")).
• Removing quotes may allow a broader search: (( improving firm performance evidence. ) or ( improving annual performance series. )).
• Adding a wildcard symbol may retrieve word variants: (("improving firm performance evidence.") or ("improving annual performance series."))*.