Study on the effect of nerve block in ward and postoperative PCIA on pain degree， pain mediators and stress state of elderly orthopedic patients during perioperative period
ZHANG Ming-min, LUO Fang-yi, PANG Bo
Journal of Hebei Medical University . 2021, (9): 1089 -1093 .  DOI: 10.3969/j.issn.1007-3205.2021.09.019