Funding for this research was provided by:
Teaching Reforming Project of PUMC (2019zlgc0105)
Received: 14 July 2020
Accepted: 27 December 2020
First Online: 11 January 2021
Ethics approval and consent to participate
: The study was approved by the Ethics Committee of Peking Union Medical College Hospital (S-K1087). Written Informed consent was obtained from all the trainees before participation in the study.
: Written Informed consent for publication of the personal data was obtained from all the participants before participation in the study.
: The authors declare that they have no competing interests.