Some of them you can. The 16"+ models with the full keyboard w/ num-pad that have ports on the right side, you can replace those without too much hassle if you know how to take a laptop case apart, they attach to the motherboard with a 6 inch or so cable. All the Toshibas I've worked on that have any ports on the left, however, those on the left are soldered on. They can be replaced, but I wouldn't suggest undertaking that if you don't have extensive training on soldering circuit boards, which I imagine you don't, or you wouldn't be asking this. It's not the same as doing wires, so please don't think "I can solder a wire, I can do this!" Things get too hot, and your machine is dead.
Hope this helps!