The 20th Century is harder because there is so much information: you could search
Also, there are many more ways to gather data. You would start in Articles Plus and ALICE, but you can also go to all these places:
Here's a "search cheat" to discover good info on specific decades in Articles Plus:
(The same idea works for ALICE, too)
Note that the second line is searching Subject Terms, not keywords. That really helps.
Here are a few of the wonderful books on 20th C costume: