Popular, free aggregating service with 45 million abstracts and 10 million full-text papers. Can be browsed by subject area. Content is 34% biology and 29% medicine. From ResearchGate GmbH in Berlin, Germany.
Finds MEDLINE citations in PubMed and uses natural language processing to extract semantic predications from titles and abstracts. The predications are used to create a drawing showing relationships between terms or concepts. A free user account must be created.