Electronic databases corresponding to most of the world's currently published literature and many other types of information are publicly available through online systems. Scientific databases that give references for publications are numerous and widely used; scientific numeric databases that are open to the public are far fewer and less used. Online retrieval systems are becoming easier to use as a result of the introduction of artificial intelligence techniques and user-friendly front ends and gateways. Issues related to electronic databases include public-private sector competition, transborder data flow, copyright, downloading, and the changing roles in database generation and processing.