Baidu knows a * *, how many classifications are there?

On the Know page, click the navigation classification above to see the specific new problems under this category in turn.

Category:/Browse/

At present, there is 14 level classification.

Every field under the first-level classification has a second-level classification, some fields have a third-level classification, and some fields have a fourth-level classification (such as regional classification). You can visually view the classification list:

/misc/alltop？ Type = All