A tractor pulse was a brief but intense burst of tractor beam energy, useful when attempting to precision-maneuver a ship or object. (VOY: "Barge of the Dead")
The Borg would use tractor pulses when capturing a ship for assimilation, as they did to a Starfleet shuttlecraft being used as a diversion by the crew of the USS Voyager in 2375. (VOY: "Dark Frontier")
That same year, Captain Janeway and Lieutenant Commander Tuvok remodulated Voyager's tractor beam to produce a series of carefully-timed tractor pulses with which to alter the trajectory of a Malon freighter which was about to explode into the corona of an O-type star. The plan worked, and the star's corona absorbed the resultant theta radiation. (VOY: "Juggernaut")