Perhaps you should try some spelling variations:
"concerns criteria" » "cancer criteria", "concept criteria", "contests criteria"
"weil's criterion" » "weyl's criterion", "kelly's criterion", "white's criterion"
"well's criterion" » "weyl's criterion", "kelly's criterion", "kelly criterion"

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: (((("weil's criterion") OR ("well's criterion"))) OR ("concerns criteria")).
• Removing quotes may allow a broader search: (((( weil's criterion ) or ( well's criterion ))) or ( concerns criteria )).
• Adding a wildcard symbol may retrieve word variants: (((("weil's criterion") or ("well's criterion"))) or ("concerns criteria"))*.