Submitted on: 24 February 2006.
Revised on: 28 March 2006.
Accepted on: 14 April 2006.
Preventive Medicine
http://reply.papertrans.cn/3/253/25214/25214-22.png
http://reply.papertrans.cn/3/253/25214/25214-23.png
Submitted on: 10 July 2023.
Revised on: 18 August 2023.
Accepted on: 13 September 2023.
Preventive Medicine
http://reply.papertrans.cn/3/253/25214/25214-25.png
http://reply.papertrans.cn/3/253/25214/25214-26.png
Submitted on: 21 October 2020.
Revised on: 27 November 2020.
Accepted on: 02 December 2020.
Preventive Medicine
http://reply.papertrans.cn/3/253/25214/25214-28.png
http://reply.papertrans.cn/3/253/25214/25214-29.png
http://reply.papertrans.cn/3/253/25214/25214-30.png