Through the use of the esp@cenet patent database, the paper demonstrates that, in many cases, the use of classification systems is a condition to good quality searching. Efficient search tools relieve the user of the in-depth familiarizing with the classification system, yet they carry out the search with the appropriate classification symbols. In the esp@cenet database, classification symbols are provided automatically, in the result lists of natural language keyword searches. These symbols are then exported into the advanced search interface with one click. Through the search examples, readers of the paper get acquainted with the tools of patent search, while they are also provided with further information on the European Patent Office's network of databases, the applied classification systems, as well as the services of the Patent Library of the Hungarian Patent Office.