Where are you getting your info? As a general rule, only government hospitals pay doctors salaries. Private hospitals don't. Doctors in private practice bill patients or the patient's medical insurance carrier.
Heavy Metals May Be Implicated In Autism
Heart may be home to its own stem cells
If you do an author search at the PNAS website, you do it this way: Leri, A
Leri has nine complete, linked articles there on the heart and regeneration at PNAS. If you find the biology interesting, check the titles and abstracts. My guess is that all of PNAS's articles are free except the newest which require a subscription.
The article of the last thread that I linked had not been posted by PNAS at the time I looked. I've noticed that sometimes they are discussed in the popular press before they are listed here. Please note that those in blue at the last link are freebies.
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