Two databases are commercial, Derwent and SciFinder/CAS. The rest are free.

Derwent Innovations Index, is part of the Web of Science family. It is a commercial database that your university library usually subscribes to. Students at Copenhagen University can access Derwent Innovation Index . The link works directly from campus computers and requires a login and password when off-site. Similarly, students from the Technical University, DTU, may access Derwent via this link. Students from Copenhagen Business School (CBS) access Web of Science here.

Derwent offers a very flexible system of hierachical database queries. Derwent furthermore neutralizes the inventors attempts to make their application non-searchable. Derwent does so by replacing the original abstract with their own using suitable keywords.

European Patent Register. This is the tool to use for determining patent status, patent family and gain access to All documents. All documents is where you can follow the comunication between applicants and patent authorities. Evaluation reports are among the most valuable documents when you want to judge the strength of an application. Covers patent families with at least one PCT or EP member.

Espacenet is the European authority. Here you may search for patents by number or by a database query, albeit of limited flexibility. INPADOC patent families can be viewed and full texts can often be accessed.

WIPO, the website of the PCT. PatentScope is their search engine.

USPTO is the patent authority of United States. They host PatFT and AppFT, patent and application full text databases here: USPTO PatFT and AppFT. Patents and patent applications can be searched by number or by data base query of limited flexibility, but the query may cover the entire patent texts. US applications have only been published after 2001.

USPTO Patent Center hosts a database which is the US equivalent of European Patent Register providing access to the transcation history between applicant and examiner.

SciFinder is a research discovery tool that allows you to search the CAS databases for patents on the basis of chemical structures. Text based searches and sequence search are also supported. SciFinder is a commercial database that your university library usually subscribes to. Students at Copenhagen University should create a personal account here, and then access SciFinder here. Likewise, students at DTU create an account here, and login here

CAS monitors, indexes, and abstracts the world's chemistry-related literature and patents comprising such fields as biomedical sciences, chemistry, engineering, materials science, agricultural science etc. Here is the entrypoint for SciFinder tutorials.

Patent document codes lists and explains almost all patent and applications number suffixes.

CIPO, the Canadian patent authorities

IPAustralia, the Australian patent authorities

PVS-Online, the Danish patent authorities

PRV, the Swedish patent authorities