Perhaps you should try some spelling variations:
"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."
"improving shared performance based." » "improving sharia performances based.", "improving care performance based.", "improving based performance based.", "improving shared performance measures.", "improving water performance based.", "improving land performance based.", "improving safety performance based."

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 shared performance based."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving basic performance series.") OR ("improving shared performance based.")).
• Removing quotes may allow a broader search: (( improving basic performance series. ) or ( improving shared performance based. )).
• Adding a wildcard symbol may retrieve word variants: (("improving basic performance series.") or ("improving shared performance based."))*.