IEEE Xplore is a digital library providing full text access to the world's highest quality technical literature in electrical engineering, computer science, and electronics. IEEE Xplore contains full text documents from IEEE journals, transactions, magazines, letters, conference proceedings, standards, and IET (Institution of Engineering and Technology) publications.
The content available in IEEE Xplore is:

IEEE journals, transactions, letters, and magazines from 1988
with select content back to 1913

IEEE conference proceedings from 1988 with select content back to 1953

IEEE standards from 1988

IET journals, letters, and magazines from 1988

IET conference proceedings from 1988

IEEE educational courses from 2006

IEEE books from 1974

Please note that IET is the new name of the IEE.