Summon currently indexes more than 200 million open access items, including articles, books, thesis, technical reports, images, and more. These items are made accessible in a variety of ways, including as full text resources (e.g. pdf, image, etc.) or through the descriptive metadata allowing you to find the full resource in open access repositories.
On the Library homepage search using Summon (General), and limit your results to openly accessible content using the “Refine Your Search” filter for “Open Access”.