Perhaps you should try some spelling variations:
"improving contract performance measures." » "improving country performance measures.", "improving court performance measures.", "improving corporate performance measures.", "improve contract performance measures.", "improving central performance measures.", "improving coverage performance measures."
"improving poor performance series." » "improving poor performance metrics.", "improving poor performance reviews.", "improving poor performance review.", "improving export performance series.", "improving sector performance series.", "improving _ performance series.", "improving power performance series.", "improving food performance series.", "improving indoor 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 contract performance measures.") or ("improving poor performance series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving contract performance measures.") OR ("improving poor performance series.")).
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• Adding a wildcard symbol may retrieve word variants: (("improving contract performance measures.") or ("improving poor performance series."))*.