Legal analysis: Patent substantive examination search methods: 1. Machine search method. When conducting computer search, in order to search as comprehensively as possible, the examiner should try as much as possible for each search element. Express it from multiple angles, such as using keywords, classification numbers, chemical structural formulas, etc. 2. Manual inspection method.
Legal basis: "Patent Law of the People's Republic of China" Article 35 Within three years from the filing date of an invention patent application, the patent administration department of the State Council may, upon request submitted by the applicant at any time, The application shall be subject to substantive examination; if the applicant fails to request substantive examination within the time limit without justifiable reasons, the application shall be deemed to have been withdrawn. When the patent administration department of the State Council deems it necessary, it may conduct a substantive examination of an invention patent application on its own.