As for the scope of search, although there are a large number of patents in the world, the topics you want to search are generally more specific, such as whether you are in the field of communication or medicine, whether you are about mobile phone equipment or software protocols, whether you are improving the structure or technology, and so on. Until you are interested in a very small branch of technology, the number of patents in each specific field is relatively limited, for example, there may be only thousands or hundreds. Therefore, we must first understand our own needs, thoroughly understand the technical contribution of retrieval inventions, and be targeted. If possible, you should know something about the international patent classification system.
There are two concepts about retrieval tools, one is retrieval platform and the other is database. All patent documents are indexed in various ways and collected in various databases, some are abstract databases, some are full-text databases, and important fields such as applicant, inventor and time can generally be used as search items. At present, there are many retrieval platforms that can retrieve these databases, and some retrieval commands will be defined to improve efficiency. So you should be familiar with such a database and retrieval platform. Different databases and retrieval platforms have their own characteristics and need to accumulate some retrieval experience. Some are more professional, some provide general search, some charge, some are free, for example, patentics, google and so on. Some platforms support concept retrieval, and you can input sentences and make semantic analysis, while some professional retrieval tools provide more complex command formats and efficient graphical browsing interfaces, but these professional tools are not easy to obtain and use. If it is an important and innovative retrieval work, it can be entrusted to a professional institution.