J-STAGE
Japan's national platform for scholarly journals — much of it open, much of it in English.
Tier 2 Open AccessFree
Research Database Directory
Every research database, reviewed.
CNKI
China's largest research database — journals, theses, and more, and often the only route to Chinese scholarship.
Tier 2 CorporateSubscription
ACM Digital Library
The definitive full-text archive for computer science — the ACM's journals, conferences, and the complete computing literature it curates.
Tier 2 AcademicSubscription
Ovid
Wolters Kluwer's search platform — one rigorous interface over many biomedical databases.
Tier 2 CorporateSubscription
WorldCat
The union catalog of the world's libraries — find who holds a book or item, and where.
Tier 2 ToolsFree
NASA ADS (Astrophysics Data System)
The free, comprehensive index for astronomy and physics — the field's shared memory.
Tier 2 Open AccessFree
MathSciNet
The American Mathematical Society's index — the authoritative, reviewed record of mathematics.
Tier 2 AcademicSubscription
zbMATH Open
The open, reviewed index of mathematics — MathSciNet's free counterpart.
Tier 2 Open AccessFree
INSPIRE-HEP
The free index high-energy physics runs on — literature, authors, data, and jobs in one place.
Tier 2 Open AccessFree
RePEc / IDEAS
The volunteer-built open bibliography of economics — with IDEAS as its main front door.
Tier 2 Open AccessFree