Knowledge and barriers on correct use of modified guidelines for active management of third stage of labour: a cross sectional survey of nurse-midwives at three referral hospitals in Dar es Salaam, Tanzania

坦桑尼亚达累斯萨拉姆三家转诊医院的助产士对改良版第三产程主动管理指南的正确使用知识和障碍：一项横断面调查