PubMed:
http://www.ncbi.nlm.nih.gov/Literature/index.html

HighWire:
http://highwire.stanford.edu/cgi/search/

John Wiley:
http://www3.interscience.wiley.com/cgi-bin/home

Ovid:
http://gateway.ovid.com/autologin.cgi

Neonatal Rat Cardiomyocyte 2D PAGE Database:
http://2d.bjmu.edu.cn/
(Provided by Dr. Li Zijian, Peking University Third Hospital, 100083, Beijing, China)