- DEPATISnet (Germany)
- Derwent World Patents Index
- Espacenet (Europe)
- FreePatentsOnline
- Google Patents
- National patent office databases
- PatentScope (WIPO)
- Questel
- USPTO Patent Full-Text and Image Database (PatFT)
- USPTO Patent Application Full-Text and Image Database (AppFT)
- Other databases
Classification of Patents:
