Perhaps you should try some spelling variations:
"improving can performance series." » "improving can performance studies.", "improving can performance size.", "improving chain performance series.", "improving loan performance series.", "improving human performance series.", "improving care performance series.", "improving a performance series.", "improving co performance series."
"improving food performance contracts." » "improving good performance contracts.", "improving fund performance contracts.", "improving bond performance contracts."

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("improving can performance series.") OR ("improving food performance contracts."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"improving can performance series.\") OR (\"improving food performance contracts.\"))".
• Removing quotes may allow a broader search: (( improving can performance series. ) OR ( improving food performance contracts. )).
• Adding a wildcard symbol may retrieve word variants: (("improving can performance series.") OR ("improving food performance contracts."))*.