Perhaps you should try some spelling variations:
cross patients » from patients, class patient, doctors patients
cross patient » class patient, proms patient, access patient
wang yang » wang yan, wang liang, wang yanling
risk tong » risk among, risk along
tong shui » tong hui, cong shu, gong hui
yang jin » yang jie, yang jun, ying jin
yang up » yang jui, tying up, yang jun

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: wang yang ((yang up) OR (yang jin)) ((cross patients) OR (cross patient)) risk tong shui ;~.
• Adding a wildcard symbol may retrieve word variants: wang yang ((yang up) or (yang jin)) ((cross patients) or (cross patient)) risk tong shui ;*.