I am searching for a quality self diagnostics expert system similar to http://www.easydiagnosis.com (seams quite good) . Are there other avaliable for free ?
There are quite a few free symptom checkers available online, for example:
You can type in symptoms or choose them from the lists of 50-90 symptoms or so.
The tools can be useful if your symptom combinations are typical for a certain disease. They can greatly narrow down the possible causes and, on the other hand, remind you of the causes you didn't think of.
The pretty much only benefit of these tools is that they may help you judge if you have a serious disease that may need to be treated by a doctor or you can let it heal on its own.
The downsides include, for example, inability to guess the exact type of infection and getting misleading results when your symptom combinations are not typical, like, say, in pneumonia without fever.