Perhaps you should try some spelling variations:
"improving seismic performance reviews." » "improving economic performance reviews.", "improving academic performance reviews.", "improving seismic performance review.", "improving seismic performance reports.", "improving seismic performance risks.", "improving semantic performance reviews.", "improving service performance reviews.", "improving basic performance reviews."
"improving past performance based." » "improving plant performance based.", "improving port performance based.", "improving transit performance based.", "improving fast performance based.", "improving post performance based."

You may be able to get more results by adjusting your search query.

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