Perhaps you should try some spelling variations:
"improving rural performance series." » "improving rural performance studies.", "improving rural performance size.", "improving euract performance series.", "improving larval performance series.", "improving pupil performance series."
"improving gender performance series." » "improving gender performance studies.", "improving gender performance size.", "improving gendered performance series.", "improving center performance series.", "improving under performance series.", "improving energy 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 rural performance series.") or ("improving gender performance series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving rural performance series.") OR ("improving gender performance series.")).
• Removing quotes may allow a broader search: (( improving rural performance series. ) or ( improving gender performance series. )).
• Adding a wildcard symbol may retrieve word variants: (("improving rural performance series.") or ("improving gender performance series."))*.