Perhaps you should try some spelling variations:
"improving pupil performance contract." » "improving pupil performance contracts.", "improving social performance contract.", "improving model performance contract.", "improving judicial performance contract.", "improving public performance contract.", "improving civil performance contract.", "improving audit performance contract."
"improving urban performance series." » "improving urban performance studies.", "improving urban performance size.", "improving bank performance series.", "improving loan performance series.", "improving human 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 urban performance series.") or ("improving pupil performance contract."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving urban performance series.") OR ("improving pupil performance contract.")).
• Removing quotes may allow a broader search: (( improving urban performance series. ) or ( improving pupil performance contract. )).
• Adding a wildcard symbol may retrieve word variants: (("improving urban performance series.") or ("improving pupil performance contract."))*.