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 trade performance series." » "improving trade performance metrics.", "improving trade performance reviews.", "improving trade performance review.", "improving road performance series.", "improving tax performance series.", "improving teacher 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 trade performance series.") or ("improving poor performance contract."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving trade performance series.") OR ("improving poor performance contract.")).
• Removing quotes may allow a broader search: (( improving trade performance series. ) or ( improving poor performance contract. )).
• Adding a wildcard symbol may retrieve word variants: (("improving trade performance series.") or ("improving poor performance contract."))*.