(3)登记号索引登记号索引是用来查找同族专利的。因为在德温特出版物中用完全相同的登记号刊出由不同国家批准的同一内容的发明专利。即每件相同专利都以其基本专利的登记号为自己的登记号。掌握一件专利的同族专利可以帮助检索人员按外语语种选用专利文献,解决未收藏的专利的利用,并了解一件发明专利的专利权的国际范围。 (3) Registration number index The registration number index is used to find the same family of patents. Because in the Derwent publications, identical invention patents of the same content approved by different countries are published with identical registration numbers. That is, each identical patent has its own registration number with its basic patent registration number. Mastering a patent family patent can help searchers select patent documents in foreign languages, resolve the use of unregistered patents, and understand the international scope of a patent for an invention patent.