A.專利文獻(xiàn)B.期刊論文C.學(xué)位論文D.會(huì)議論文
A.Peking Univ AND hosp B.Peking Univ SAME hosp C.Peking Univ WITH hosp D.Peking Univ NEAR hosp
A.PubMed B.SinoMed C.EMBASE D.CINAHL