Sometimes a smelly dog is the sign of an infection. My Samoyed is allergic to flea saliva. If he gets bitten once, he begins stinking and losing hair. I keep him on Frontline and I keep my yard doctored, as fleas and ticks are bad here.
Also, due to the heat and humidity here, he frequently suffers from yeast infections on his skin. My vet recommended daily yogurt. He said most dogs love the strawberry/banana kind, and of course Sam does, I've discovered. I figure the yogurt helps in so many ways and Sam considers it a special treat. Perhaps this is a dietary supplement option for your dog.
But speak to your vet about the smell. Different "stinks" can tell a vet the real problem, whereas we're all just guessing. Sam smells different with a flea bite infection than he does with a yeast infection, and the treatment options are different.