Reference Books both print and online have many resources on world cultures.
To most effectively search books use the phrase - with quotes: "Indians of North America"
Add specific terms such as health, medicine, medical
You will find books such as the ones below with "indians of north america" medicine
Another good subject search is Transcultural Care
Searching Transcultural Care in CINHAL retrieves articles from journals such as:
Note: use Native Americans as an additional subject term
Under More Search Options
Ethnic Group allows you to limit your results