List of studies on Covid-19 identified in PubMed and excluded from our systematic review

In the course of our PubMed searches we identified and screened the title and abstract of a number of studies on Covid-19 that were finally excluded from our systematic review. This file will be updated regularly.在PubMed数据库检索过程中，我们识别并筛选了多篇针对新冠病毒感染（Covid-19）的研究的标题与摘要，但上述研究最终均被排除在本系统综述之外。本文件将定期更新。