bear down in WordNet English dictionary

1. exert a force or cause a strain upon
   "This tax bears down on the lower middle class"
   bear down 
   
2. pay special attention to
   "The lectures bore down on the political background"
   bear down 
   
3. exert full strength
   "The pitcher bore down"
   bear down 
   
4. to make a rush at or sudden attack upon, as in battle
   "he saw Jess charging at him with a pitchfork"
   charge  bear down 
   
5. exert a force with a heavy weight
   "The snow bore down on the roof"
   drag down  bear down  bear down on  press down on  weigh down 
   
6. contract the abdominal muscles during childbirth to ease delivery
   bear down  overbear 
   

bear down in English Wiktionary