Good resource to learn scientific Chinese
I know of a couple resources for medicine and chemistry. These are technical dictionaries. You can start checking these out. I used to use them for work and never had problems so I guess the translations should be correct. Will post more as I come across them.

Medicine:
drdict.com

Chemistry:
cosdna.com


EDIT:
If you're looking for occasional term references, usually a good bet is to search Wikipedia and switch to the Chinese page.