Library Genesis - Wikipedia

Library Genesis or LibGen is a search engine for articles and books on various topics, which allows free access to content that is otherwise paywalled or not digitized elsewhere at all. Among others it carries PDFs of content from Elsevier's ScienceDirect web-portal.

a search engine for articles and books on various topics,[1] which allows free access to content that is otherwise paywalled or not digitized elsewhere at all

Via Mark E. Deschaine, PhD