University Libraries

Scholarly articles about the history of the Americas includes social topics like costume history.

Articles, books, museum bulletins, etc., back to 1984. Includes discussions of textiles, jewelry, costume, art. Art Index Retro goes back to 1929.

Covers theater, costume, history, dance, film, etc., back to 1864.

Journals articles, books & chapters, dissertations, for when your topic includes a psychological angle.
Note: Learn to use the PsycINFO thesaurus; it makes better searches.

Does your topic need a sociological perspective? Here are core sociology journals as old as 1895.

Currently individual subscription ; looking into library subscription. .
The Fashion and Race Database gathers resources from far and wide having to do with its titular interest. Articles, books, videos, exhibits, and other information is searchable by keyword and browsable by topic. Note: some articles are not free; ask if you need help.
Don't stop with the library, though: "Objects that Matter" covers x-cultural fashion items such as the Boubou and the veil; "Profiles" covers people and trendmakers, and other sections do more and more.