Partial paralysis and weakness can look very similar, even to a trained eye. Partial paralysis typically results in a very unsteady gait, falling down, and/or knuckling over of the paws.
Weakness is usually more associated with a tendency for the dog to sit or lay down frequently during what is typically normal activity. The ability to go up stairs or get up from a lying position is often impaired with general weakness.
Complete paralysis results in complete inability to use the limbs at all, and in severe cases, there may be no sensation to touch.