The governing board of the Smithsonian Institution yesterday stared down congressional critics of apartheid and declined to sell its remaining $34 million of stocks in companies that do business in South Africa.

The announcement was made by Smithsonian Secretary Robert McCormick Adams after a meeting of the 17-member Smithsonian Board of Regents.

Earlier this summer the Smithsonian sold $9.6 million of its portfolio when those investments in companies that operate in South Africa drew fire at a congressional hearing.

The regents agreed on their "personal abhorrence of the entire apartheid system," Adams said, but the majority remain unconvinced that divestment is an effective or moral course of action given the "the fluid and rapidly changing situtation" in South Africa and the continuing evolution of U.S. policy there.

Currently, the Smithsonian has $34 million, or one out of every five dollars of its approximately $147 million portfolio, invested in companies that do business in South Africa. Included among those 35 companies are blue-chip firms such as Armco Inc., Bristol-Myers Co., Caterpillar Tractor Corp., Deere and Co., IBM, Eli Lilly & Co., Texaco Inc. and Union Carbide Corp.

In June, after criticism from some members of Congress, the Smithsonian's executive committee sold $9.6 million in stock in 15 corporations that had not signed the so-called Sullivan principles, voluntary guidelines for U.S. companies in South Africa that are designed to improve the living and working conditions of nonwhite employes.

There was no formal vote taken at yesterday's meeting, Adams said, but the majority of the board concluded that the Smithsonian should undertake no further divestment until U.S. policy toward South Africa is further defined. The board members include Chief Justice Warren E. Burger and Vice President George Bush. The vice president did not attend yesterday's meeting, Adams said.

The board meetings are closed to the public, but sources close to the board say the push for divestiture was led by Rep. Norman Y. Mineta (D-Calif.), one of six congressional regents. Mineta said yesterday that the regents had agreed not to purchase any more stock in companies that have not signed the Sullivan principles.

Earlier, Mineta had said that the Smithsonian "cannot stand aloof from this great national debate while holding stock in firms that do business in South Africa."

While Chief Justice Burger disapproves of apartheid, sources close to the board said yesterday, he reportedly believes, along with a majority of other regents, that the Smithsonian, as a quasi-federal institution, should not appear to be moving ahead of U.S. policy in that area.

One congressional critic, however, labeled the regents' decision "mumbo jumbo."

"The board ought to be ashamed of itself," said Rep. Mary Rose Oakar (D-Ohio), coauthor of a bill that would require the Smithsonian to divest itself within a year of all investments in companies doing business in South Africa. "The Smithsonian is supposed to be the greatest cultural institution in the world. It sends a terrible message to the rest of the world when that institution has one out of five dollars invested in South Africa. . . . "

Adams said the regents have instructed him to continue to investigate the Smithsonian's options and to cooperate with a consortium of U.S. colleges and universities that are considering divestiture of South African investments.