As physicians, we are essentially not allowed to do that. If you're writing a research paper for any journal, any grant you receive you must declare up front, and that's to rule out the conflict of interest that you are suggesting: “My project was funded by”--we'll say--“Taser, and I found that tasers are really great devices.” In a medical paper you have to declare it right up front.
On April 28th, 2008. See this statement in context.