Use and effect of short acting β-agonist trials in children aged 2–59 months presenting with respiratory symptoms in low-, middle-, and high-income, primary care settings.

Use and effect of short acting β-agonist trials in children aged 2–59 months presenting with respiratory symptoms in low-, middle-, and high-income, primary care settings.短效β-激动剂（short acting β-agonist）试验在低、中、高收入经济体基层医疗环境中，针对因呼吸道症状就诊的2至59月龄儿童群体的应用与效果