You don't get specialization course through NEET. The scores of NEET provide you to do MBBS only and if your rank is good you get a chance to be in one the good medical colleges. You can later choose on specialisation after doing MBBS by giving exam called NEET-PG. So, if you want to become an anesthesiologist you have to first do MBBS and then only you can get specialization in anesthesia.