The databases below are all ways to find magazine and newspaper articles that could constitute PRIMARY sources, depending on your specific topic, because they will lead you to articles published before, during, and right after WWII.
The databases listed below are quite different. They offer access to mostly PRIMARY sources in their focused subject areas.
In reading the fine print and the footnotes and references in your secondary sources, you may get names of organizations and resources that are housing primary sources. These kinds of resources are constantly being digitized and made available over the internet. So, you can use Google to see what is available from any particular group.
You can find primary sources through a Google search attaching phrases like "primary sources" to a search:
navajo code talkers "primary sources"
or even the word documents: navajo code talkers documents
The various museums and collections that comprise the Smithsonian Institution, the National Archives, and the Library of Congress have created some marvelous internet tools, exhibitions, collections and databases. A quick way to "get in" is to construct complex Boolean search statements to use in a Google search following these three patterns:
word (or phrase enclosed in " ") site:si.edu
word (or phrase enclosed in " ") site:loc.gov
word (or phrase enclosed in " ") site:archives.gov
For example, if I wanted to see what was available about the Navajo code talkers during World War II, remembering that "less is often better searching", I would do these three separate searches in Google:
"code talkers" site:si.edu
"code talkers" site:loc.gov
"code talkers" site:archives.gov
and find some incredible resources.
If your research has a California focus, you have a truly unique resource available to you in the Online Archive of California which includes primary source collections from over 200 institutions, libraries, archives, historical societies, museums, including the Bancroft Library at Berkeley. It's growing all the time, too!