Digital library of academic journals, books, and primary sources.
If you're not finding results, try different search terms. The library subjects assigned to a book or article won't always be the most widely used or current words that you know and expect.
For instance, if you're looking for information on nonbinary people, a keyword search for "nonbinary" will generate results, but it may not find all of them. Then, if you want to follow a result, to chain together like materials by using linked subject headings, the subject headings you see will be "transgender people", "gender identity", "gender nonconformity", "gender-nonconforming people".