研究设计：随机对照试验的系统评价。
Study Design. A systematic review of randomized controlled trials.
非随机对照试验的系统评价与随机对照试验的系统评价一样是普遍开展的。
Systematic reviews of non-randomized studies are as common as reviews of randomized controlled trials.
还查看了现有系统评价文献以及上述方法确定的所有试验的参考资料目录。
We also checked the reference lists of existing systematic reviews and of all trials identified by the above methods.
应用推荐