About 155 million DOIs total

Crossref
 => ~100 million total, ~80 million papers

Datacite
 => ~13 million total (or was is 8mil?)

ISTIC
 => 27 million journal DOIs (29 million total)

CNKI
 => 11 million?
 => "China Academic Journals Full-text Database" => 11146 titles, 64222243 articles

KISTI
 => http://www.doi.or.kr/wordpress/
 => http://www.doi.or.kr/wordpress/oai-pmh/ (requires registration)
 => 7 million?

JaLC (Japan Link Center)
 => ~6.6 million
 => started 2012


### Other Random Stuff

Open Access Korea
  http://central.oak.go.kr/
  "OAK Central is a full-text XML service based on Journal Article Tag Suite (JATS) for domestic OA scholarly papers."
  10k articles

http://koreascience.or.kr/MainPage.jsp
  hundreds of thousands of records? maybe fulltext links?

Korean Journal Publishing Service
  http://kpubs.org/index.kpubs
  some 88k articles