Perhaps you should try some spelling variations:
"improving poor performance contract." » "improving poor performance contracts.", "improving export performance contract.", "improving sector performance contract.", "improving _ performance contract.", "improving power performance contract.", "improving food performance contract.", "improving indoor performance contract."
"improving can performance series." » "improving can performance metrics.", "improving can performance reviews.", "improving can performance review.", "improving bank performance series.", "improving loan performance series.", "improving care performance series.", "improving land performance series.", "improving tax performance series.", "improving co 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 can performance series.") or ("improving poor performance contract."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving can performance series.") OR ("improving poor performance contract.")).
• Removing quotes may allow a broader search: (( improving can performance series. ) or ( improving poor performance contract. )).
• Adding a wildcard symbol may retrieve word variants: (("improving can performance series.") or ("improving poor performance contract."))*.