All of these resources can also be used as primary sources in the history of anthropology in the United Stares.
Biodiversity Heritage Contains ethnological works especially on Native Americans. Use search box on home page to find full-text materials on specific topics (e.g. Cherokee). Specific publications of interest are listed below.
Annual Report of the Board of Regents of the Smithsonian Institution Note alternative titles.
Annual Report of the Bureau of Ethnology Continues above title.
Bulletin (Smithsonian Institution. Bureau of Ethnology) Continues the above title.
The following link, also from the Smithsonian, provides a partial index.
Smithsonian Library: Digital Library Books and other materials. Included are the Annual Reports of the Regents of the Smithsonian Institution, Annual Reports of the Bureau of Ethnography, both going back to the 19th century. A rich collection of material on Native Americans and on natural history. Some of this is reproduced in the Biodiversity Heritage site.
The Internet Archive and HathiTrust contain many of the items listed above and can be searched for at least some of the Smithsonian materials. One can also extract authors' names and titles of works from the index and then search for specific items in the Smithsonian sites.