George Bush kept his underdog candidacy for the GOP presidential nomination alive last night with a resounding upset over Ronald Reagan in the Michigan Republican primary. Reagan and President Carter, meanwhile, swept to easy wins in the Oregon primary, moving ever closer to clinching their respective party nominations. With 99 percent of the precincts in Michigan reporting, Bush had 57 percent of the vote, Reagan 32 percent and Rep. John B. Anderson, who has dropped out of the race to run as an independent, 8 percent. The rest were uncommitted. Carter and Kennedy were not on the Michigan Democratic ballot. Democrats there selected delegates in caucuses last month, with Kennedy edging Carter, 71 to 70. In Oregon, with 55 percent of the precincts reporting, Reagan had 57 percent, Bush 33 percent and Anderson 9 percent. In the Democratic race, Carter led with 59 percent of the vote to Kennedy's 32 percent. California Gov. Edmund G. (Jerry) Brown Jr., who dropped out of the race earlier, had 9 percent. But the results did not reverse the basic arithmetic of the Republican race. Reagan still holds a 4-to-1 lead in delegates, and CBS and Abc News declared he had locked up the nomination. However, other delegate counts, including Reagan's own, showed him just short of the nomination. Reacting to the results at a late-night Santa Barbara press conference, Reagan credited Michigan Gov. William G. Milliken for Bush's victory and congratulated not his opponent but the governor. At the same time, Reagan came as close as he ever has to declaring that he had clinched the nomination. "When the networks say you're over the top, I'm not going to argue," Reagan said. "I think we ought to start planning for the convention and beyond." Bush's Michigan margin of victory was his biggest of the year, and raised new questions about Reagan's ability to carry industrial states outside his traditional conservative base in the South and West. The only two large state primaries he has carried outside this base were Wisconsin and Illinois, where Anderson campaigned as a Republican. Bush's sixth primary victory -- against 17 for Reagan -- came at a time when his candidacy teetered on the verge of financial collapse and much of the party had conceded the nomination to Reagan, the former movie actor and California governor. Turnout was extremely low in Michigan, the only state where Bush, the former ambassador and CIA director, has had the support of a major statewide political figure -- Gov. William G. Milliken. The primary created so little excitement that not a single voter turned up during the first two hours of balloting in one Detroit precinct. In Cleveland, an exuberant Bush said, "I'm elated. It was a magnificent win. I'm very, very pleased." The win, he said, "means I shouldn't be written off. I've been trying to make this point over and over again." With the nomination still just beyond his grasp, Reagan said, "The future looks very good." "We've made a step forward toward the nomination," he said in a statement issued through a spokesman in Los Angeles. "Based on the officially selected delegates, we're very optimistic." White House press secretary Jody Powell called Carter's victory in Oregon "significant," while Kennedy shrugged off the loss, saying, "We didn't expect to win there." Reagan, regardless of last night's results, is still within a hair of the GOP nomination. Exactly how close is in dispute. Before last night, United Press International said Reagan needed 59 delegates. But Associated Press, the competing wire service, put the number at 157, and the Bush campaign placed it even higher. Other news organizations had still different counts. "I just can't let myself accept any one of the delegate counts I read as definite," Reagan said. "But I must be within shooting range." United Press International projected Bush capturing 53 delegates to Reagan's 29 in Michigan, and 11 to Reagan's 18 in Oregon. Carter, it said would pick up 26 delegates to Kennedy's 13 in Oregon. This would bring Carter's delegate total to 1,550 of the 1,999 needed for nomination. In Michigan, Bush swept all regions of the state and outpolled Reagan among virtually every demographic group. According to exit polls by ABC News, he outpolled Reagan three to one among Catholics and union members, two groups Reagan has fared well among in past industrial-state primaries. With campaign coffers nearly empty, Bush said he would press the Ohio and New Jersey primaries on June 3, but said his plans for California that day "depend on the money." The campaign has raised only one-sixth of the $600,000 it considers necessary to mount a major effort against Reagan in his home state, and it is feeling the pinch in other states. Last night, a half-hour television show in Ohio was canceled at the last minute because the $50,000 production cost was not available. Yesterday's primaries gave candidates Kennedy and Bush a chance to retain some respectability. Yet Kennedy, in effect, wrote off Oregon as not worth the effort by spending less than 24 hours in the state, to the chagrin of local supporters. And since Michigan Democrats had already given him 71 of the state's 141 delegates in party caucuses on April 26 and his name did not even appear on the primary ballot, there was no need for him to return to that state. Bush, however, made major efforts in both states, hoping to keep Reagan from wrapping up the nomination. He spent more time and far more money in both states than front-runner Reagan. With only two weeks of primaries remaining, the battle over the delegate count promises to heat up. Each television network, candidate and wire service has a different count. Before yesterday's primaries, CBS and ABC, who declared that Reagan had locked up the nomination last night, gave the former California governor 955 and 963 delegates respectively. NBC gave him a more conservative 816 delegates. CBS gave Carter 1,514 delegates, ABC 1,261 and NBC 1,288. Republican Bush and Democrat Kennedy argue that delegate counts kept by their opponents and news organizations exaggerate Carter and Reagan strength and make it difficult for them to attract support. And indeed a feeling that Carter and Reagan have their party nominations wrapped up has come to dominate the campaign. Hundreds of thousands of voters have simply stayed away from recent primaries. This is in marked contrast to the record number of voters who participated in early primary states. Kennedy and Bush concede they are far behind in delegate counts. But their numbers put a slightly better face on the situation. Kennedy maintains Carter has 1,290 "firm" delegates and 254 "soft" ones, compared to his own 724 "firm" and 108 "soft." A total of 1,666 delegates is required for the Democratic nomination. By Bush's count, he has 208 legally bound delegates and 127 unbound delegates; Reagan 824 bound and 457 unbound; Anderson 56 bound; Senate Minority Leader Howard Baker, who has endorsed Reagan, 4; and 93 delegates are uncommitted. Republicans require 998 delegates' votes for the nomination. a Bush has based his strategy on the fact that 49 percent of the GOP convention delegates will not be legally bound to any candidate. He theorizes that if he could score a string of upsets in the final big state primaries in Ohio, Michigan, California and New Jersey delegates would desert Reagan in droves. On the Democratic side, Kennedy has a similar strategy. In addition to the delegates he picked up in Oregon, Carter appeared to take an early lead in a straw poll among Utah Democrats which will determine the allocation of the state's 20 delegates.