Perhaps you should try some spelling variations:
"improving central performance evidence." » "improving control performance evidence.", "improving general performance evidence.", "improving contract performance evidence.", "improving mental performance evidence.", "improving federal performance evidence.", "improving neural performance evidence."
"improving loan performance series." » "improving loan performance studies.", "improving loan performance size.", "improving local performance series.", "improving land performance series.", "improving lead 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 loan performance series.") or ("improving central performance evidence."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving loan performance series.") OR ("improving central performance evidence.")).
• Removing quotes may allow a broader search: (( improving loan performance series. ) or ( improving central performance evidence. )).
• Adding a wildcard symbol may retrieve word variants: (("improving loan performance series.") or ("improving central performance evidence."))*.