My boss' brother is a cop and former animal control officer for one of the larger departments in the Twin Cities. His advice when attacked by a single dog and unarmed is to ball up one hand into a fist and try to shove it as far in the dog's mouth as possible. It will be too big to swallow, and hands are both fairly tough and fairly free of exposed arteries. The other hand is then free to grab the dog's throat and lift it off the ground, or choke it or body slam the critter. Most dogs weigh less than half what an adult human does...we have mass on our side.
Now for three dogs...he said "You'd better have a gun."