Perhaps you should try some spelling variations:
"improving co performance contract." » "improving co performance contracts.", "improving ceo performance contract.", "improving do performance contract.", "improving core performance contract.", "improving eco performance contract.", "improving crop performance contract.", "improving ict 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."

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 co performance contract."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"improving local performance series.\") OR (\"improving co performance contract.\"))".
• Removing quotes may allow a broader search: (( improving local performance series. ) OR ( improving co performance contract. )).
• Adding a wildcard symbol may retrieve word variants: (("improving local performance series.") OR ("improving co performance contract."))*.