5Akiba T. Coatinuous wave Doppler echocardl graphic evaluation of the changes in pulmonary artefia./pressure during the first seven days of life [J]. Am J Catdiol. 2005. 89:479 -481.
6Jadad AR, Moore A, Carroll D, et al. Assessing the quality of reports of randomized clinical trials:is blinding necessary? [ J]. Control Clin Trials, 1996,17 ( 1 ) : 1 - 12.
