Perhaps you should try some spelling variations:
"improving land performance series." » "improving land performance studies.", "improving land performance size.", "improving plant performance series.", "improving fund performance series.", "improving und performance series."
"improving beef performance evidence." » "improving e performance evidence.", "improving de performance evidence.", "improving die performance evidence.", "improving deep performance evidence.", "improving feed performance evidence.", "improving burn performance evidence."

You may be able to get more results by adjusting your search query.

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