There are a lot of headings, but you don't have to know specific headings to make use of them. If you find a book or article in the library catalog (or another database) that seems like it's a good fit for your research, take a look at the item's subject headings, and click on them to find other items that may be similar. Names of authors are also subject terms, so you can also find other items written by them or about them.
I ran a search for intersectionality in UC Library Search, the library catalog, and I found an eBook titled Intersectionality as critical social theory (2019) by Patricia Collins Hill.
It includes these subject terms:
The last two don't seem especially specific, but the heading on critical theory is very relevant. By clicking on it, you can discover other items that are also tagged with critical theory,
While this doesn't bring us to other specific items on intersectionality (it doesn't have an outright heading), keyword searching may be more helpful. There is not one perfect search, so you will need to use a combination of different strategies to discover information. Searching is an exploration.