Perhaps you should try some spelling variations:
"improving basic performance contract." » "improving basic performance contracts.", "improving based performance contract.", "improving bank performance contract.", "improving past performance contract.", "improving air performance contract.", "improve basic performance contract.", "improving public performance contract."
"improving basic performance series." » "improving basic performance metrics.", "improving basic performance reviews.", "improving basic performance review.", "improving based performance series.", "improving bank performance series.", "improving past performance series.", "improving air performance series.", "improve basic performance series.", "improving public 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 basic performance series.") or ("improving basic performance contract."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving basic performance series.") OR ("improving basic performance contract.")).
• Removing quotes may allow a broader search: (( improving basic performance series. ) or ( improving basic performance contract. )).
• Adding a wildcard symbol may retrieve word variants: (("improving basic performance series.") or ("improving basic performance contract."))*.