Where can I search for antidumping rates online (by commodity type or most recent)?

The U.S. Customs and Border Protection maintains a searchable database of antidumping and countervailing duty messages that can be retrieved based on simple or complex search characteristics using keywords and Boolean operators. The messages are segregated by Antidumping or Countervailing and span the years 1992 to present.

https://trade.cbp.dhs.gov/ace/adcvd/adcvd-public/#