Perhaps you should try some spelling variations:
"improving level performance contract." » "improving level performance contracts.", "improving model performance contract.", "improving revenue performance contract.", "improving pupil performance contract.", "improving legal performance contract.", "improving lives performance contract.", "improving civil performance contract."
"improving local performance series." » "improving local performance studies.", "improving local performance size.", "improving social performance series.", "improving global performance series.", "improving total performance series.", "improving fiscal 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 local performance series.") or ("improving level performance contract."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving local performance series.") OR ("improving level performance contract.")).
• Removing quotes may allow a broader search: (( improving local performance series. ) or ( improving level performance contract. )).
• Adding a wildcard symbol may retrieve word variants: (("improving local performance series.") or ("improving level performance contract."))*.