[1] Qingdao Chengyang Dist Peoples Hosp, Dept Thorac Surg, 600 Changcheng Rd, Qingdao 266109, Shandong, Peoples R China
[2] Qingdao Chengyang Dist Peoples Hosp, Dept Gynaecol, 600 Changcheng Rd, Qingdao 266109, Shandong, Peoples R China
[3] Qingdao Chengyang Dist Peoples Hosp, Dept Gastroenterol, 600 Changcheng Rd, Qingdao 266109, Shandong, Peoples R China