Perhaps you should try some spelling variations:
"improve past performance studies." » "improve past performance audits.", "improve past performance audit.", "improve past performance standards.", "improve plant performance studies.", "improve port performance studies.", "improve transit performance studies.", "improve post performance studies.", "improve asi performance studies.", "improve cost performance studies."
"improving rural performance metrics." » "improving rural performance measures.", "improving euract performance metrics.", "improving larval performance metrics.", "improving pupil performance metrics."

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