A good place to start your search for primary sources is in the UO Library & Summit catalogs.
The UO Libraries belong to the Center for Research Libraries, an international consortium that provides access to unique and unusual collections of library materials international in scope, and comprehensive in disciplines. Use CRL Catalog for quick access to CRL collection info. Use Interlibrary Loan to borrow from CRL, as well as microfilm and other materials.
LibrarySearch offers a streamlined interface for finding books and other media that combines the collections of UO Libraries and Summit libraries.
In order to search a library catalog effectively, it is helpful to know something about Library of Congress Subject Headings. LC Subject Headings (LCSH) are standardized terms developed by the Library of Congress to describe materials listed in library catalogs and to make it easier to arrange them by topic.
LCSH terms are not always the first terms that come to mind. For instance, the LC Subject Heading for World War II is 'World War 1939 1945' and the subject heading for the Salem witch trials is 'trials (witchcraft) Massachusetts Salem'. See the Keyword search strategy below for tips on identifying appropriate LC Subject Headings for your search.
Some of the LCSH subheadings that point to primary sources include:
Search by Keyword in the library catalog using various terms for your topic paired with the subheadings listed above. This will identify some of the relevant sources available in the UO Libraries or Summit. Note the LC Subject Headings so you can use them to search by Subject to find more information on the same topic.
Search by Author in the catalog to find the writings of a known author or names of groups or organizations. e.g. Carson, Rachel OR National Association for the Advancement of Colored People.
There are a number of institutions and corporations scanning books and putting them up online, but the best place to start is Google Books, which gives full or partial access to numerous books; full-text access is generally restricted to books published before 1930 (though this date changes according to copyright law).