ScienceDirect是世界上科学研究出版的最大在线收藏。出版商是荷兰的爱思唯尔公司，包含了大约一千一百万篇文章、2500种期刊、6000多册电子图书、参考书、手册，这些文章分为以下几个主要部分：

ScienceDirect is a website which provides subscription-based access to a large database of scientific and medical research. It hosts over 12 million pieces of content from 3,500 academic journals and 34,000 e-books. The journals are grouped into four main sections: Physical Sciences and Engineering, Life Sciences, Health Sciences, and Social Sciences and Humanities. Article abstracts are freely available, but access to their full texts (in PDF and, for newer publications, also HTML) generally require a subscription or pay-per-view purchase.