What are you looking for? Here are a few starting points which may help:
Try the Princeton University Library Catalog.
eBooks can be found by searching in the Princeton University Library Catalog There is a guide with links to a select set of books relevant for Plasma Physics and Fusion Energy at http://libguides.princeton.edu/pppl-ebooks or try Ebrary, CRCnetBASE, Knovel Engineering and Scientific References, MyIlibrary - International Atomic Energy Agency collection or Safari Tech Books to search directly in one of our engineering and science eBook collections.
Try SciTech Connect from the DOE's Office of Scientific and Technical Information or the PPLCat (catalog of articles and technical reports in the PPL Library: 1986-2011). PPPL reports from 1950s to around 2005 can be searched in the Princeton Library main catalog. Digital PPPL reports from 1995+ search the PPPL Publications page.
Encyclopedias and Reference?
Try Encyclopedia of Astronomy and Astrophysics, Encyclopedia of Applied Physics, Handbook of Physics and Chemistry, NRL Plasma Formulary (the mini-Bible of Plasma physicists), NDS Atomic and Molecular Data Unit, or search in an eBooks collection.
Try the Plasma Physics Conferences page.