Ethics approval and consent to participate
Our study was conducted as per the requirements of the ethical guidelines of the Helsinki Declaration. Besides, this study was approval by the Ethics Committee of the Air Force Medical University. Before the investigation, the research purpose was explained to the participants, verbal consent was obtained from them before conducting the survey and the informed consent form was also signed by them. Informed consent was obtained from all study participants. During the investigation, participants was able to terminate and withdraw from the investigation at any time and the questionnaire was completely anonymously.