This topic studies the steps of patent retrieval. The steps of patent search according to patent classification are: (1) searching patent names and translating names in different languages; (2) search the patent classification number in alphabetical order; (3) use the classification table to check or further find the classification number of the subject; (4) according to the classification number to find the patent number; Search the abstract of patent specification by patent number. Therefore, ABD is correct;
The steps of searching according to the inventor's name are as follows: (1) Verify the name of the patentee or its affiliated company and the name of the patent itself through the patentee index; (2) according to the patent number to find the abstract of the patent specification. Therefore, CE is wrong; Therefore, the correct answer to this question is ABD.