Perhaps you should try some spelling variations:
"improving animal performance series." » "improving annual performance series.", "improving thermal performance series.", "improving fiscal performance series.", "improving animal performance studies.", "improving animal performance size.", "improving initial performance series.", "improving optimal performance series.", "improving criminal performance series."
"improving human performance evidence." » "improving loan performance evidence.", "improving thermal performance evidence.", "improving chain 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 human performance evidence.") or ("improving animal performance series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving human performance evidence.") OR ("improving animal performance series.")).
• Removing quotes may allow a broader search: (( improving human performance evidence. ) or ( improving animal performance series. )).
• Adding a wildcard symbol may retrieve word variants: (("improving human performance evidence.") or ("improving animal performance series."))*.