http://www.worldscinet.com/subject.shtml
http://www.scientificjournals.org/
http://en.wikipedia.org/wiki/Impact_factor
CONSORT randomized controlled trials:
http://www.consort-statement.org
STARD studies of diagnostic accuracy:
http://www.stard-statement.org
QUOROM systematic reviews and meta-analyses:
http://en.wikipedia.org/wiki/QUOROM_flow_chart
STROBE observational studies in epidemiology:
http://www.strobe-statement.org
MOOSE meta-analyses of observational studies in epidemiology:
http://www.consort-statement.org/Initiatives/MOOSE/moose.pdf