Thrifty effect of subanesthetic‐dose S‐ketamine on postoperative opioids and its safety and analgesic effectiveness: A prospective, triple‐blind, randomized controlled, polycentric... oleh Jun Ding, Yun‐Mei Yu, Man Luo, Xu Fang, Dan‐Dan Tan, Han‐Rui Qin, Xue‐Feng Ren, Yong‐Guo Zhang, Tao Luo, Lei Chen, Wan‐Qiu Yu, Zhao‐Qiong Zhu