Academic Search Engines and Repositories

📄 arXiv
A free distribution service and open-access archive hosting over 2.6 million scholarly articles in physics, mathematics, computer science, and related fields

🌐 CORE
The world’s largest multidisciplinary aggregator of open-access research papers, offering machine access to 316 million documents harvested from repositories and journals

🔍 Google Scholar
A broad scholarly search engine indexing articles, theses, books, abstracts, and court opinions across a vast array of disciplines and sources

📚 Internet Archive Scholar
A free search engine indexing over 35 million research articles and scholarly documents preserved in the Internet Archive, from 18th-century journals to modern preprints

📑 CiteSeerX
An evolving digital library and search engine focused on literature in computer and information science, offering access to abstracts, citations, and full-text documents

📖 JSTOR Open Content
A curated selection of open-access ebooks, journals, and primary-source collections across multiple disciplines, freely available to the public

📗 Directory of Open Access Journals (DOAJ)
An extensive index of high-quality, peer-reviewed open-access journals spanning all disciplines, driven by a global community committed to open scholarship

📄 Social Science Research Network (SSRN)
A repository for working papers, preprints, and published articles in the social sciences and humanities, including economics, law, and business

⚡ IEEE Xplore
A digital library of over 5 million documents—journals, conference proceedings, standards, and ebooks—published by IEEE and partner organizations in engineering and technology

📂 ScienceDirect Open Access Journals
A collection of 3.3 million peer-reviewed, open-access articles across physical sciences, engineering, life sciences, and social sciences, freely available to read and download