Many stories about scientific discoveries originate with peer-reviewed journals.

These weekly, biweekly and monthly publications—which the research community uses to disseminate its latest findings—often make their contents available to journalists in advance of publication as long as reporters abide by the journals' embargo rules. Below is information on how to gain access to the major scientific journals.

The Single Most Valuable Website

The most valuable resource for science news is EurekAlert!, a Web site managed by the American Association for the Advancement of Science. Registered journalists can access advance information on studies being published in more than a dozen scientific journals. To sign up, go to www.eurekalert.org, click on "register," and fill out the form. You can also register to receive a daily e-mail digest with the latest science-related press releases. The most important journals accessible through EurekAlert! are: JAMA (Journal of the American Medical Association), The Lancet, PLoS (Public Library of Science), PNAS (Proceedings of the National Academy of Sciences), and Science.

The Big Four

Four prestigious journals provide the lion's share of newsworthy studies.

Nature

A weekly journal of science covering all fields except clinical medicine. Published in the UK every Thursday. Material is embargoed until Wednesday at 1:00 PM ET. To sign up for embargoed news, go to http://press.nature.com and click on "Apply to Register." Once you've registered, you'll able to see full contents of the journal in advance of publication and you'll receive a weekly e-mail detailing the contents of the upcoming issue. At the NatureWeb site you can also access Nature's many specialty journals, including Nature Biotechnology, Nature Genetics and Nature Medicine.

Contact: Rachel Twinn (London office) r.twinn@nature.com, www.nature.com.

Science

Nature's chief competitor, Science also covers all fields except for clinical medicine. Science is published every Friday by the American Association for the Advancement of Science and is embargoed until Thursday at 2:00 PM ET. You can gain access to contents of the upcoming issue through EurekAlert! (see above). Each Monday morning you can also receive a weekly e-mail that outlines potentially newsworthy studies in that Friday's issue.

Contact: Natasha Pinol, (202) 326-7088, npinol@aaas.org, www.sciencemag.org.

New England Journal of Medicine (NEJM)

Arguably the most prestigious general medical journal in the world, NEJM [pronounced NEE-jum] is published every Thursday by the Massachusetts Medical Society. Contents are embargoed until Wednesday at 5:00 PM ET. To register for access to embargoed news, go to http://media.nejm.org and click on "apply for a media subscription." Once you've registered you can access the journal's full contents online and receive a weekly press release outlining what's in the upcoming issue.

Contact: NEJM Media Relations, (781) 434-7847, mediasupport@nejm.org, www.nejm.org.

Journal of the American Medical Association (JAMA)

JAMA, NEJM's main competitor, is published every Wednesday by the American Medical Association. Contents are embargoed until Tuesday at 4:00 PM ET. You can gain access to contents of the upcoming issue and sign up for a weekly e-mail news release through EurekAlert! or directly with JAMA at www.jamamedia.org. Either way, you can also access JAMA's sister publications, including Archives of Dermatology and Archives of Pediatrics.

Contact: JAMA Media Relations Dept., (312) 464-5262, mediarelations@jama-archives.org, www.jama.ama-assn.org.

Other Journals

The Lancet

An international medical journal published in the UK every Saturday. Material embargoed until Thursday at 6:30 PM ET. Press releases for selected studies are available at EurekAlert!. To receive a weekly e-mail of the journal's full contents, and to request studies in advance, e-mail Martine Persico (below).

Contact: Martine Persico, (212) 633-3810, m.persico@elsevier.com, www.thelancet.com.

Proceedings of the National Academy of Sciences (PNAS)

PNAS, published every Tuesday by the National Academy of Sciences, is a huge journal containing dozens of studies in almost all areas of science. Prior to print publication, PNAS publishes its studies in an online "early edition," at which time the contents are available for reporting by the news media. Studies are generally embargoed until Monday at 5:00 PM ET. You can gain access to PNAS and sign up for a weekly e-mail news release through EurekAlert!.

Contact: PNAS News Office, (202) 334-1310, PNASnews@nas.edu, www.pnas.org.

Public Library of Science (PLoS)

The PLoS journals (PLoS Biology, PLos Medicine, etc.) are "open-access," meaning that they make their contents available for free over the Web. Most studies are embargoed until Monday at 5:00 PM ET. You can gain access to PLoS journals and sign up for e-mail news releases through EurekAlert!.

Contact: PLoS News Office, (415) 624-1200, press@plos.org, www.plos.org.

British Medical Journal (BMJ)

Published every Friday. Contents embargoed until Thursday at 7:00 PM ET. You can access news releases for contents of upcoming issues through EurekAlert!.

Contact: Rachael Davies, 011-44-207-383-6529, rdavies@bma.org.uk, www.bmj.com.

Morbidity and Mortality Weekly Report (MMWR)

The U.S. Centers for Disease Control and Prevention (CDC) publishes MMWR to disseminate brief reports about communicable diseases and other issues relevant to public health professionals. Published every Friday, MMWR is embargoed until Thursday at 12:00 PM ET. To sign up for a weekly e-mail that summarizes the upcoming issue's contents, contact CDC's Division of Media Relations.

Contact: CDC Division of Media Relations, (404) 639-3286, in.the.news@cdc.gov, www.cdc.gov/mmwr.