Perhaps you should try some spelling variations:
among masters » among partners, among farmers, among actors
patients 19 » patients 1, patients 6.9, patients 7.9
yan yang » yang yang, yao yang, dan yang
wai yan » wang yan, wei yang
fan de » jan de, can de
aan de » jan de
van de » van der, van den

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: wai yan yang ((((fan de) OR (aan de))) OR (van de)) patients 19 among masters ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wai yan yang ((((fan de) OR (aan de))) or (van de)) patients 19 among masters ;~".
• Adding a wildcard symbol may retrieve word variants: wai yan yang ((((fan de) OR (aan de))) or (van de)) patients 19 among masters ;*.