This large database includes both scholarly works and patent documents from around the world. In addition to its specialized search features, it includes analytical tools that can be used to identify influential people, institutions, publishers, and journals in a particular research area. Click here for tutorial
This is a free website that will allow you to enter a U.S. patent number and retrieve a PDF version of the patent. The documents are drawn from the USPTO file server and it does not require any special software to view the images.