Acknowledging that the nation's sick economy has been slow to heal, President Reagan in his second State of the Union message last night called for bipartisan enactment of a "realistic" four-point budget plan he contended would spur recovery and reduce mounting federal deficits.

"We who are in government must take the lead in restoring the economy," the president said, and received in response the only standing ovation given him by Congress during the 45-minute speech. After the applause had subsided, Reagan cracked, "And here all that time I thought you were reading the paper."

Much of the time, Reagan's delivery was uncharacteristically halting as he appealed, in a nationally televised address, for help from Democrats and Republicans alike in halting the slide of the nation's economy. His speech included specific programs designed to appeal to the jobless, women and minorities--groups with which Reagan's popularity has plummeted in recent months.

Though the president stuck by some essentials of the programs he has espoused throughout his political career--cuts in domestic spending, a large defense budget and a tough posture toward the Soviet Union--his speech also demonstrated the pragmatism he has always shown under pressure.

His budget plan acknowledged the need for eventual tax increases if the economy does not recover, called for some slowdown in the rate of defense spending increases and ratified the compromise Social Security agreement that requires both tax rises and a slowdown in benefit increases.

Reagan used the word "bipartisan" seven times during the course of a speech that contrasted both in tone and provisions with the optimistic "New Beginning" approach of his first State of the Union speech a year ago. He was interrupted 26 times by applause, though much of it seemed tepid.

"Right now we need both realism and idealism," the president said, in touching on the No. 1 national problem of unemployment. "Millions of our neighbors are without work. It is up to us to see that they are not without hope."

Reagan made clear, however, that he was not among those who are "without hope." He said, as he did a week ago at a mini-press conference, that "America is on the mend" and said that the nation was pulling out of the recession in which it has been mired for nearly two years.

The sharpest contrast between last year's speech and the present one came in the president's discussion of the growing federal deficit, which will reach nearly $190 billion in fiscal 1984, according to the administration's estimate.

A year ago Reagan confidently predicted that "the policies we have in place will reduce the deficit steadily, surely and in time completely." Last night, he took a starker view, saying: "The deficit problem is a clear and present danger to the basic health of our republic."

While the president expressed confidence last night that the four-point economic program he outlined would ultimately succeed, both his speech and his demeanor reflected the gravity of the domestic problems facing the country and his administration.

Earlier in the day Reagan dropped in at a luncheon briefing of television anchormen and was asked by one of them, NBC's Roger Mudd, whether his plan was enough to get him out of the "political doldrums" and the country out of the recession. After throwing a good-natured barb at the anchormen--implying that conditions would be better if television said they were--Reagan added:

There is no point in trying to worry about image or anything in a situation of this kind. You just have to do what you think needs to be done. And, if you are right, that will take care of itself. And, if you are wrong, as Mr. Lincoln said: 'All of the angels in heaven couldn't change the situation.' "

The president offered no new foreign policy initiatives in a speech that was largely devoted to the economy as the nation suffers from the most severe recession since the Great Depression.

While he said that "we are now prepared for a positive change in Soviet-American relations," he emphasized that the "Soviet Union must show, by deeds as well as words, a sincere commitment to respect the rights and sovereignty of the family of nations.

"Responsible members of the world community do not threaten or invade their neighbors and they restrain their allies from aggression," the president said.

He slightly hardened an earlier draft of the speech in his statements about the Soviet Union at the same time he was reworking many of the passages dealing with domestic issues to make them sound more conciliatory or bipartisan.

Reagan reaffirmed his earlier proposals to reduce both strategic nuclear arms and intermediate nuclear weapons in Europe but made no new offers.

"With firmness and dedication, we will continue to negotiate," the president said. "Deep down, the Soviets must know it is in their interest as well as ours to prevent a wasteful arms race."

One of the most unequivocal passages in the president's speech reaffirmed his commitment to free trade, but it was greeted by silence in a Congress becoming increasingly protectionist.

" . . . As a country that has become great and rich because of economic freedom, America must be an unrelenting advocate of free trade," Reagan said.

What he called his four-part budget plan for economic growth included these elements:

"A federal spending freeze" that is largely a six-month delay in cost-of-living payments to Social Security recipients and a one-year freeze on federal pay and some domestic spending programs. Under this selective freeze, defense spending will increase 14 percent and domestic spending about 2 percent, according to senior administration officials. This is less than the estimated 5 percent inflation rate.

Controls on specific spending programs, such as food stamps, where the growth is based on eligibility and cannot be specifically frozen. Reagan repeated his frequent charges that such programs contain "waste and corruption."

A $55 billion slowdown in defense spending, with most of the savings coming from deferment of promised military pay increases. Reagan inserted a sentence saying he was "sorry" about the military pay freeze and in another section of his speech claimed with pride that "our armed forces are finally properly paid."

Tax increases beginning in fiscal 1986 that would be triggered if the deficit forecast by the administration on July 1, 1985, exceeds 2 1/2 percent of the gross national product.

Reagan said that an employment act he will soon propose to Congress will extend unemployment benefits, provide tax credits for job retraining programs and extend special incentives to employers who hire the long-term jobless.

The president also called for elimination of wage discrimination based on sex and on removing inequities in pensions based on sex. Various surveys show that the administration's standing with women is far lower than it is with men.

Reagan also called for extension of the Civil Rights Commission, due to expire this year, and for "effective enforcement of our nation's fair housing laws . . . . "