SECRETARY of State James Baker III had a tough business trip to China. He endured lectures from his hosts on the glory of their history, lengthy negotiations best described by the word "stonewall," and grudging, last-minute concessions that delayed his departure. And in the end, all he got was a diplomatic deal that the White House head office admitted was disappointing on a major point - human rights.Congressional detractors of the Bush administration's China policy are not likely to be impressed by the results of the Baker trip. They're sure to reemphasize their belief that threatening punishment through trade sanctions is the best way to get China to ease suppression of its people. "The initial results of Secretary Baker's trip demonstrate that the Bush China policy has failed," charged Rep. Nancy Pelosi (D) of California, a leading critic of administration Chinese actions, this week. To Baker, the accords reached in Beijing were the minimum necessary to claim success. As a positive result he pointed to Chinese agreement to join the international missile technology control regime - if the United States lifts sanctions on Chinese firms that sold missile technology to Pakistan and allows sales of satellite equipment and high-speed computers to China. Baker also lauded China's firm pledge to accede to the Nuclear Non-Proliferation Treaty by March 1992, and an agreement to help keep prisoner-made Chinese products out of the US market. But much of the Baker visit focused on improving China's human rights record in the wake of the 1989 Tiananmen Square crackdown. On that the Chinese gave little; no large prisoner release promise, for instance, as Baker had hoped. The secretary of state had gone to China admitting that the gulf on the human rights question was wide, but in the end even White House spokesman Marlin Fitzwater said Monday, "We're very disappointed.... One of the major missions Secretary Baker took to China was to try to get progress on human rights." Mr. Fitzwater said it was too early to tell if there would be trade repercussions as a result of this disappointment, but he didn't rule them out. Congressional Democrats, for their part, are trying to make the renewal of China's most-favored-nation trading status conditional on human rights and other reforms. Congresswoman Pelosi said any move by the Bush administration to lift sanctions on high-speed computer sales to China would be met with stiff congressional resistance. The accords reached on the China trip at best involved "cosmetic" concessions, said Chong-Pin Lin, associate director of China studies at the American Enterprise Institute. Such an outcome was predictable, he said: for Beijing to give ground under the public urging of a Western power would make it look "cheap," in Chinese terms. But Mr. Lin still judges the Baker visit one worth undertaking. He thinks Beijing could well be withholding its concessions until the last possible minute for maximum leverage. "This is preparation for something more to come" said Lin, perhaps closer to the 1992 elections when Bush would benefit more from a political boost.