Perhaps you should try some spelling variations:
"improving initial performance series." » "improving animal performance series.", "improving intel performance series.", "improving individual performance series.", "improving initial performance studies.", "improving initial performance size.", "improving critical performance series.", "improving spatial performance series."
"improving thermal performance series." » "improving thermal performance studies.", "improving thermal performance size.", "improving external performance series.", "improving animal performance series.", "improving erm performance series."

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• Performing a fuzzy search may retrieve terms with similar spellings: (("improving initial performance series.") or ("improving thermal performance series."))~.
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