Searching in free online databases will give you an inital overview of basic patent information, which you can use as a source of inspiration. However, querying these databases cannot replace a professional search by an expert.

• Swissreg
  If you are looking for a patent with effect in Switzerland, Swissreg is the right database for your search.

• Espacenet
  If you want to search for relevant patents, then Espacenet is the right database. The European Patent Office's database contains more than 90 million patent documents from all over the world with information on inventions and technical developments from 1836 up to the present day.

Almost all patent offices publish their national patent applications and granted patents in publicly accessible databases. Here are some important ones:

• PATENTSCOPE
  Using this system of the World Intellectual Property Organization (WIPO), you can search 3.6 million international patent applications (PCT) and 77 million patent documents from regional and national patent collections.
• Patent Lens
  This database is maintained by Cambia, an international non-profit research organisation in Australia, which is supported by the WIPO and the FAO (Food and Agriculture Organization of the United Nations). The database contains more than 90 million documents from around the world.

• DEPATISnet
  The database of the German Patent and Trade Mark Office (DPMA) offers similiar services to Espacenet. It covers data worldwide.
• USPTO (USA)
  Contains US patent specifications including design patents and plant patents.
• UK IPO (United Kingdom)
  Contains UK patent specifications.
• JPO database (Japan)
  Contains Japanese patent literature.
• CNIPA database (China)
  Contains Chinese patent literature.
• KIPO Datenbank (Südkorea)
  Contains South Korean patent literature.

Patent classifications are classification systems in which patent documents are organised based on the technical concepts described in them regardless of language and terminology. There are various such systems in use. The following are two of the most important:

• International Patent Classification (IPC)
  This is available on the website of the WIPO in English and French and on the website of the German Patent and Trade Mark Office in German.
• Cooperative Patent Classification (CPC)
  This is available on Espacenet. However, it is only possible to do the classification search in English.