A fair use statement regarding the full text of the request

Your requested [星系M51中致密气体与恒星形成研究] is currently limited to Purple Mountain Observatory，Chinese Academy of Sciences internal sharing.

To solicit author authorization, you need to provide the following information: name, organization, personal e-mail, reason for request. The information you provide will be reviewed and you are committed to the truth of the information provided. The personal information you provide will be protected according to law.