Perhaps you should try some spelling variations:
"improving farmers performance series." » "improving firms performance series.", "improving markets performance series.", "improving workers performance series.", "improving farmers performance studies.", "improving farmers performance size.", "improving access performance series.", "improving care performance series."
"improving fiscal performance evidence." » "improving financial 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 fiscal performance evidence.") OR ("improving farmers performance series."))~.
• Removing quotes may allow a broader search: (( improving fiscal performance evidence. ) or ( improving farmers performance series. ))~.
• Adding a wildcard symbol may retrieve word variants: (("improving fiscal performance evidence.") or ("improving farmers performance series."))*.