Perhaps you should try some spelling variations:
"improving human performance series." » "improving human performance studies.", "improving human performance size.", "improving loan performance series.", "improving thermal performance series.", "improving chain performance series."
"improving road performance review." » "improving road performance risk.", "improving road performance evidence.", "improving board performance review.", "improving good performance review.", "improving bond performance review.", "improving food performance review.", "improving rural performance review."

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