COMMANDER SAYS NATO BOMBS HURT ALL SERB FORCES
NATO Commander, Gen Wesley K Clark, in first comprehensive assessment of campaign against Yugoslavia, says that allies have damaged every sector of Serbian military; says that Pres Slobodan Milosevic appears determined to ride out air war and shows no sign of withdrawing from Kosovo; will seek more allied warplanes, pushing armada to over 1,000 aircraft; says reinforcements will include 300 additional US planes; says Yugoslavia military is potentially 'vulnerable to collapse' if enough military pressure is applied; maps; photos (M)

