Understanding the outcome and management of children aged 2-59 months with chest indrawing pneumonia: a study protocol for an observational study in Ethiopia, India, Nigeria, Pakistan, Uganda and Zambia

了解2-59个月龄儿童胸廓凹陷性肺炎的预后和治疗：一项在埃塞俄比亚、印度、尼日利亚、巴基斯坦、乌干达和赞比亚开展的观察性研究方案