please excuse me replying to you in English. There is absolutely no difference between the educational version and the full version of Premium. If you buy the educational version you will need to send proof to Nuance that you are indeed entitled to such, e.g. university tuition fees, school tuition fees etc. You will be able to buy the software from a reseller no problem but when you open the box there will be no activation code until you have e-mailed the relevant information to Nuance and then received your activation code in return.
You can only buy full versions of DNS with educational versions as far as I aware, at least in the UK. The idea being that they are so relatively cheap that if you do want to upgrade you just buy the new full educational version. The other option you have is that you can buy the normal upgrade version and this will also upgrade an educational version.