PubMed Central (PMC)
The free full-text archive behind PubMed — biomedical papers you can actually read.
Tier 2 Open AccessFree
Research Database Directory
Every research database, reviewed.
Google Dataset Search
Google for datasets — one search box across millions of data repositories.
Tier 2 ToolsFree
DataCite
DOIs for data — the identifier registry that makes datasets citable.
Tier 3 ToolsFree
ORCID
A unique ID for every researcher — the thread that ties a career's work together.
Tier 2 ToolsFree
ROR
A persistent ID for every research organization — ORCID for institutions.
Tier 3 ToolsFree
PubPeer
Post-publication peer review — where the community flags what the journals missed.
Tier 3 ToolsFree
Retraction Watch
The database of retractions — know when a paper has been pulled.
Tier 2 Open AccessFree
Sciety
Preprint evaluations in one place — see which preprints experts have vetted.
Tier 3 ToolsFree
Internet Archive Scholar
Full-text search of the preserved scholarly record — including the hard-to-find.
Tier 3 Open AccessFree
Paperity
An aggregator of open-access papers — one search across gold and hybrid OA.
Tier 3 Open AccessFree