Perhaps you should try some spelling variations:
"improving mental performance measures." » "improving general performance measures.", "improving senegal performance measures.", "improving annual performance measures.", "improving maternal performance measures.", "improving fiscal performance measures.", "improving gender performance measures."
"improving human performance reports." » "improving loan performance reports.", "improving thermal performance reports.", "improving chain performance reports.", "improving human performance report."

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