Google Scholar - Stand on the shoulders of giants (Tracking is 'free')
Indiana University - Digital Library of the Commons
Check out the DLC to find international literature including free and open access full-text articles, papers, and dissertations.
Infomine - UC Riverside LIbrary
The Infomine is an incredible tool for finding scholarly Internet resource collections, especially in the sciences.
Internet Public Library
Find resources by subject through the Internet Public Library’s database.
Microsoft Academic Search
Microsoft’s academic search engine offers access to more than 38 million different publications, with features including maps, graphing, trends, and paths that show how authors are connected.
Search the OAIster® database to find millions of digital resources from thousands of contributors, especially open access resources.
Refseek - Comprehensive Knowledge Search
With more than 1 billion documents, web pages, books, journals, newspapers, and more, RefSeek offers authoritative resources in just about any subject, without all of the mess of sponsored links and commercial results.
Semantic Scholar - A free, AI-powered research tool for scientific literature
Virtual LRC - Virtual Learning Resources
The Virtual Learning Resources Center has created a custom Google search, featuring only the best of academic information websites. This search is curated by teachers and library professionals around the world to share great resources for academic projects.
Wolfram|Alpha is a unique engine for computing answers and providing knowledge
Using expert-level knowledge, this search engine doesn’t just find links; it answers questions, does analysis, and generates reports.