Training in full range of motion (ROM) will stimulate more growth.
By working in full ROM, you are covering the entire area of the muscle. Full ROM can also prevent INJURIES, and improve the quality with which you work your muscles. Full ROM actually applies good stress to your connective tissue.
Also, your body adapts to being able to give 100% no matter how much of your muscle is worked, compared with only doing half reps, where only half of the muscle is used to giving 100%.
You can even burn more calories by activating more of the muscle. The bottom line is full ROM will give you BETTER strength and muscle gains than half-ass training.