Theoretical

Journal of Physics G
Nuclear and Particle Physics Journal from the Institute of Physics (UK)
http://www.iop.org/Journals/jg

NN-OnLine
The Nijmegen database of nucleon-nucleon and hyperon-nucleon experimental scattering data, phase shifts, partial wave analyses, and potential models.
http://nn-online.org/

Nuclear Theory section of arXiv (lanl) preprint server
About half a dozen new articles in nuclear theory get submitted here every weekday, most of them en route to paper journals. Archives go back to 1992 and can be searched.
http://arxiv.org/archive/nucl-th

Physical Review C
Major Journal of Nuclear Physics. All articles back to volume 1 in 1970 are available for download.
http://prc.aps.org

Table of the Nuclides (at LANL)
Containing Moller and Nix evaluation as well as experimental data
http://t2.lanl.gov/data/map.html