[1] Gen Hosp Heilongjiang Agr Reclamat, Med Dept, Harbin 150088, Peoples R China
[2] Harbin Med Univ, Dept Policy & Hosp Management, Sch Publ Hlth, Harbin 150081, Peoples R China
[3] Linkou Cty Maternal & Child Hlth Hosp, Dept ENT, Mudanjiang 150081, Peoples R China
[4] Heihe First Peoples Hosp Heihe, Dept Cardiol, Heihe 157600, Heilongjiang, Peoples R China
[5] Harbin 6 Senior High Sch, Harbin 150000, Peoples R China
[6] Harbin Med Univ, Dept Policy & Hosp Management, Sch Hlth Management, Harbin 150081, Peoples R China
[7] Harbin Med Univ, Sch Publ Hlth, Dept Med Human Resource, Harbin 150081, Peoples R China
[8] Harbin Med Univ, Sch Publ Hlth, Dept Social Med, Harbin 150086, Peoples R China