AAAS  American Association for the Advancement of Science

ACSWeb from the American Chemical Society

American Association for the Study of Liver Disease

American Cancer Society

American College of Cardiology

American College of Chest Physicians

The American Diabetes Association

American Federation for Medical Research

American Heart Association

American Liver Foundation

The American Lung Association

American Medical Association Home Page

AAMC  Association of American Medical Colleges

FASEB Information Services  Federation of American Societies for Experimental Biology

FASEB Societies:
American Association of Anatomists
The American Association of Immunologists
  (AAI)
American Physiological Society  (APS)
American Society for Biochemistry and Molecular Biology  (ASBMB)
American Society for Bone and Mineral Research
American Society for Clinical Investigation
The American Society of Human Genetics
American Society for Nutrition
American Society for Pharmacology and Experimental Therapeutics  (ASPET)

The Biophysical Society

The Endocrine Society

The Protein Society

Society for Developmental Biology

Federation of European Biochemical Societies

The Foundation Center  Locate private sources for research funding.

GrantsNet  A compendium of funding opportunities for training in the biological and medical sciences

The Howard Hughes Medical Institute

International Cytokine Society

The Physiological Society

The Society For Free Radical Biology and Medicine  (formerly The Oxygen Society)

Oxygen Club of California  Annual meetings, including sessions on NO

NAS/NAE/IOM/NRC  The National Academy of Sciences, etc.

Research America  A US medical research advocacy organization. Only 3 cents of each Health dollar is spent on research; here’s an organization trying to change that.