bear down vs bear down on

bear down and bear down on both are verbs.

Word	Noun	Adjective	Verb	Adverb
bear down	No	No	Yes	No
bear down on	No	No	Yes	No

As verbs, bear down and bear down on are synonyms defined as:

Other synonyms of bear down include drag down, press down on, weigh down.

bear down (verb)	bear down on (verb)
exert a force or cause a strain upon	exert a force with a heavy weight
pay special attention to	sail towards another vessel, of a ship
exert full strength
to make a rush at or sudden attack upon, as in battle
exert a force with a heavy weight
contract the abdominal muscles during childbirth to ease delivery