(abbreviations: VU - Vrije Universiteit Amsterdam, UVA - Universiteit Van Amsterdam, math. library, UBM - Universiteit Van Amsterdam, central library, journals collection, TUDelft - Technical University Delft, SU - Stockholm University)
other lists
Serial and Journals database from Zentralblatt.Abbreviations of names of serials indexed in Math. Reviews
Retrodigitized Mathematics Journals and Monographs by Ulf Rehmann.
Backlog of mathematics research journals, Notices AMS, November 2009.
(silly) journal rankings: [eigenfactor] [Australian Math. Soc.]
(some) archives
AMS - new issues alertsACM Digital Library how to get papers from ACM
Cambridge Journals Online including new issues alerts
Digital Library of Chinese Math. (Tsinghua Univ.) [free]
EBSCO [commercial]
EMIS [free]
[!] Göttinger Digitalisierungs-Zentrum [free]
hvar.is - Icelandic portal to journals [free from Iceland]
J-Stage (repository of papers in Japanese (mainly non-mathematical) journals) [free]
JSTOR [list of math journals] [list of finance and OR journals]
Locus - SIAM journals 1952-1996 [free]
LANL library - contains Los Alamos reports (Ulam et al.); see also sciencemadness.org and fas.org
[!] NUMDAM - journals and old french seminars [free]
[!] Project Euclid [semi-commercial]
ProQuest [commercial]
[!] ScienceDirect - Elsevier, including new issues alerts [semibroken] [some journals published by Elsevier are total crap]
[!] Springer: journals serials new issues alerts [not reliable; doesn't work in Opera; moronic email support]
Wirtualna Biblioteka Nauki. Kolekcja matematyczno-fizyczna [free] [email address is broken]
World Scientific, including new issues alerts [slow and semibroken] [archives] [conferences proceedings]
[!] High Energy Physics (understood broadly) preprints (contain many scans of some otherwise not available articles, including mathematical ones, in preprint form): [SPIRES] [KISS]