|Patentscope is a free online search engine for patent data. The database has 74 million patent documents including 3.6 million published international patent applications (PCT).
|Escapenet is a free online service for searching patents and patent applications through the support of the European Patent Office (EPO).
|Google Patents (AJOL)
|Google Patents is a freely accessible search engine that indexes patents and patent applications. The database has over 120 million patent publications from 100+ patent offices around the world.