"做fellowship不是为了成为specialist 而是为了进一步subspecialize":
clinical fellowship training is indeed for specialist of certain subspeciality. for example, a general Ob/Gyn physician (only had residency training) usually shall refer a gyn cancer patient to a fellowship trained gyn oncologist in their area. the gyn oncologist can practice general ob/gyn & gyn oncology,because she/he are board certified for both, but a residency trained Ob/Gyn physician cannot practice gyn cancer as she/he does not hold such board certificate. In reality, a specialist makes more money with relatively less work load.