Perhaps you should try some spelling variations:
selecting patients » selecting patient, select patients, selecting incidents
patients si » patients _, patients 1, patients en
pooling shu » pooling sub
wang liang » wang yang
si pooling » _ pooling, risk pooling
yang jui » yang judy, yang di, yang xi
yang up » tying up, yang jun, hang ups

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 liang ((yang up) OR (yang jui)) selecting patients si pooling shu ;~.
• Adding a wildcard symbol may retrieve word variants: wang liang ((yang up) or (yang jui)) selecting patients si pooling shu ;*.