The National Center for Health Statistics -  .

Ask the Medical Expert - - Answers to medical related queries searchable from archives of the weekly column.

AskDrWalker - - Resources and links to medical information. Includes medical databases, medical search engines, diseases and conditions and useful links for health professionals and patients.

Best Evidence Topics - - Access to evidence-based medicine topics. Includes a searchable database.

Building Better Health - - Medical and healthcare information on disease and health improvement topics. Includes medical news, clinical research and newsletters.

CDC Health Topics A to Z - - A listing of disease and health topics from the Center for Disease Control and Prevention in the United States.

Centre for Medical Web Research - - A virtual centre for researching medical questions on the internet.

DiagnosisHealth.com - - An online forum discussing various medical topics.

DiagnosisHeart.com - - Information on heart disease with surgical data and related resources.

Disease Conditions and Information - - A reference guide for about 100 disease and health conditions in an alphabetical listing.

DocMD.com - - Provides links to free medical and medically-related sites.

Doctor NDTV - - Information on a variety of health issues from medical experts. Includes FAQ.

Doctor's Desktop - - Tables and charts for practicing medical professionals. It also provides an ECG course by e-mail.

The Doctors Page - - Links to patient education materials, medical reference sites and medical humor.

eMedicine - Consumer Treatment Guidelines - - Textbook on the treatment of common medical problems.

Essent Medical Library - - A patient-oriented health resource provided by the Essent Healthcare system.

Family Practice Reference Guides - - ABFP's 19 Reference Guides from FamilyPractice.com.

Globalrph - - Provides drug information, intravenous drug dilution standards and online clinical dosing calculators for health care professionals.

Guide to Clinical Preventive Services - - The 1996 update report of the U.S. Preventive Services Task Force (USPSTF) at the CPMC website.

Harrison's Online - - Regularly updated online version of the medical textbook. Subscription required with free 4-week trial.

Health Information Library - - Alphabetical listing of health information topics by the Carle Clinic and Hospital.

Healthsites UK - - A portal to medical and health information for patients and doctors. Access medical and NHS healthcare sites plus news, advice and complementary therapy resources.

The Healthy Forum - - Provides post-diagnosis advice on health, wellbeing and complementary medicine.

The Homeless Handbook - - An online manual designed to assist support workers of homeless and similarly disadvantaged people who find themselves in medically challenging situations.

HospitalWeb - - Directory of medical resources for professionals.

Library of the National Medical Society - - Links to various journals, online diagnosis, medical textbooks and atlases. Subscription required.

Longevity Healthy Aging Research Group - - Information from this Canadian organisation on getting older and staying healthy.

MDconsult - - Includes reference books, journal search, practice guidelines, patient education and drug information. Subscription required with free 10-day pass.

MedCalc - - A comprehensive collection of online clinical calculators. Includes ABG, GFR, Fluids and BMI calculations and interpretations.

MedConnect - - Information services with a clinical and practical focus for physicians and other health care professionals.

Medical Knowledge Base - - Offers discussion forums on topics like cancer, AIDS, arthritis, hepatitis, healthy nutrition and motivation.

Medics Travel - - Lists hospitals, charities, NGOs and recruitment agencies around the world to help doctors, nurses and medical students plan work and electives overseas.

Mediresource - - Information on diseases and conditions, support groups and drug information. Primarily patient-oriented.

Mednav.com - - A guide to resources in medicine and science. Links reviewed by experts, projects with the Journal of the AMA and the journal Science and software tools are offered on the site.

MedPix - - Database of medical images including radiology, pathology, and dermatology. Case of the Week with CME for physicians and CNE for nurses.

MedServ Medical News - - Provides medical information and news to medical professionals worldwide.

The Merck Manual - - Online version of The Merck Manual of Diagnosis and Therapy.

MerckMedicus - - Links to health resources for patients, professionals and an online medical library.

My Body - - Interactive symptom checker, includes details of some possible causes.

NCEMI: Common Simple Emergencies - - An online manual with detailed instructions and illustrations on how to treat various everyday medical emergencies.

OHSU Health - - Information for patients and clinicians on aspects of healthcare. Includes an index of health topics.

PedsCCM File Cabinet - - A resource of original and distributed educational and practical materials for pediatric critical care practitioners.

Physicians Online - - Provides physicians with free access to core services, including MEDLINE, email, private physician discussion groups, full text medical news articles, financial news and stock quote services. Membership required.

PolyMedicine.com - - Clinicians review electronic medical information resources available in any of the following media: browsable WWW sites, downloadable datasets and software or CD-ROMS.

Predictonline - - A testing and awareness site to provide the public and healthcare provider with medical information on various medical conditions.

Prescriptions of The Country Doctor - - A collection of informative and current articles issues written by John G. Hipps MD on various health topics.

PreventDisease.com - - A patient-oriented portal for up-to-date health information on fitness, lifestyle, nutrition and health tools.

RJ's Medical Directory - - A collection of medical links and information categorized by specific topics.

South African Health Information - - Reviewed, evidence-based health information based on the South African health system.

Talk Medical - - Offers information on diseases, disorders, medications, parenting, and pregnancy. Also contains a searchable medical dictionary.

TheMediweb - - Provides a medical dictionary of health information for research and education for health care professionals, academics and the general public.

Virtual Hospital - - A digital health sciences library at the University of Iowa for health care providers and patients.

Virtual Naval Hospital - - A digital library designed to help primary care providers and to help patients associated with naval medical issues. A service of the U.S. Navy Bureau of Medicine and Surgery.

Well-Connected - - Offering over 100 in-depth reports on physical and mental diseases and wellness issues. Written by medical writers and reviewed by a board at Harvard Medical School. Some information available free but most requires paid access.