A defensive President Bush insisted Tuesday that his young administration, far from lacking content and direction, is proceeding apace in filling top government jobs and developing its domestic and foreign policies.

During a wide-ranging news conference, held as the Senate moved toward possible rejection of his nomination of John Tower as defense secretary, Bush professed to be unbothered by suggestions he is off to a slow and uninspired start."I would simply resist the clamor that seems to be bubbling around that nothing is happening," he said. "A lot is happening - not all of it good, but a lot is happening."

Bush dismissed the latest political assessments of his presidency as "light compared to a year ago" when he was still fighting for the GOP nomination and he voiced confidence the public will judge him on performance, not perceptions.

"That's why I feel so relaxed," he added.

Forced by bad weather to cancel a trip to Pennsylvania and Delaware, Bush appeared before reporters for more than 30 minutes to defend the "prudent" pace of his presidency while admitting the fight over the Tower nomination had been "an inhibiting factor" in developing a full national security agenda.

Bush opened the session by calling for a negotiated settlement of the strike against Eastern Airlines (see A1.)

On other issues, Bush:

-Said he was encouraged that the reductions in conventional arms proposed Monday in Vienna by Soviet Foreign Minister Eduard Shevardnadze "look like he's moving toward the oft-stated position of NATO."

-Indicated further improvements in Soviet foreign policy and human rights could lead to a liberalization of economic relations with the United States.

-Took a cautious view of the impact recent attacks by the Palestine Liberation Organization might have on U.S.-PLO dialogue, while saying a flat condemnation of such violence by PLO Chairman Yasser Arafat "would do wonders."

Some 46 days into office, Bush was presiding over a government still awaiting his imprint in the form of appointees to shape and execute the policies of a man who once eschewed the "vision thing."

And if the slow start has been a source of mild disappointment, the Tower debacle looms as a serious political blow to his relations with Congress and the favorable early public attitudes toward his leadership abilities.

Beneath public expressions of hope and indignation, Bush has been forced to brace for a bruising defeat in his first real muscle-flexing confrontation with the Democratic leaders of the Senate.

However, Bush brushed aside recent portrayals of his administration as "groundless stories, insisting he was quick to propose a bailout of the savings and loan industry, a budget that offered "far more detail" at this point than those offered by his two predecessors, a "substantive" trip to Asia and consultations with the NATO allies and the Kremlin.

As a further gauge of progress, Bush said he had announced 67 appointments to top jobs by March 6 and noted President Reagan had made only 55 such announcements at the same point eight years ago.