Trade ministers from 88 major trading countries, including the United States, today failed to agree on specific steps to promote free trade but adopted a resolution pledging "to resist" the growth of protectionism.

The 17-page resolution was approved after an all-night session by the conference of the General Agreement on Tariffs and Trade (GATT), with members of the European Community refusing to give up their farm subsidy program, and several other countries registering reservations on key points.

Countries expressing reservations refuse to be bound by the language of the document worked out during six days of often acrimonious bargaining.

U.S. trade representative William E. Brock said after the conference concluded, "Success was only partial overall, the results might get a grade of C. It could stretch to a C plus, but only time and future actions will tell."

He added: "We did not achieve results on [farm] subsidies, for example. Regarding agriculture, we moved forward on a new, constructive basis. The direction is clear, but the distance is not as far as we would have liked."

Before going into the final meeting early this morning, that adopted the document by consensus, Brock said, "I don't think Congress will be happy with some elements of the agreement," and later he added that the administration will do everything possible to see that Congress does not pass protectionist legislation.

Congress has been pressuring the Reagan administration for protectionist measures against countries that restrict American goods, particularly farm products.

But Brock said that "substantial gains" were made in a number of key areas. He mentioned progress on nontariff barriers to trade, a study on the feasibility of bringing trade in services such as banking and insurance under free-trade rules and better means of settling disputes among trading partners.

The centerpiece of the document, which was submitted by the conference chairman, Canadian Foreign Minister Allan MacEachen, is a general commitment by GATT members "to resist" protectionist forces.

But a written statement issued by the European Community at the final session said it considered the undertaking on protectionism to merely mean that "best efforts will be deployed to avoid taking or maintaining such measures." The declaration would have GATT members commit themselves "to reduce trade frictions and overcome protectionist pressures."

In the document members also agreed to a "major work program on agriculture," but the statement by the European Community said that this "is not a commitment by the community to any new negotiations or obligations in relation to agricultural products."

French Foreign Trade Minister Michel Jobert said he hoped the United States would take "a measured and pragmatic approach." He said he felt "the United States expected far too much."

The document also includes sections calling for freer trade in fishery products, textiles and clothing, tropical products and high technology goods.

Although controversy over a number of issues had dogged the conference from its outset Wednesday, the main stumbling block and the focal point of media attention has been the Europeans' refusal to agree to roll back the community's agricultural export subsidies in the face of demands from the United States and almost all other participants in the conference.

The United States, supported strongly by a number of other agricultural exporting countries, including Australia and New Zealand, had asked the ministers to authorize a GATT study of the impact of the subsidies on free trade in farm goods, with the aim of phasing them out. The European Community, which sees the subsidies as an integral part of its common agricultural policy, has refused from the start of the negotiations to accept any study that was aimed at the rollback of the subsidies.

The conference was extended for more than 40 hours beyond its originally scheduled closing date in efforts to overcome the strong differences among participants but in the end was able to only adopt a watered-down document.

Australia announced it "is not able to associate itself" with the final document. A statement circulated to the media here on behalf of J.D. Anthony, Australian minister for trade and resources, describes the document as "papering over a number of the real issues," and full of words that are "vague, ambiguous and shrink from firm commitments."

The developing countries group also announced that, while it does not intend to oppose the final text of the meeting as a block, member nations will be free to take formal exception to certain portions.

According to Brazilian Ambassador George Maciel, a leading spokesman for the group, "Some of our members see the final results as worse than was expected and others see them as better than was hoped for."

Many developing countries are understood to be disappointed with references in the final text to a study through GATT on the feasibility of bringing world trade in services, such as banking and insurance, under free trade rules. They feel that this study will lead to an even more powerful role for the United States and other industrialized countries in their banking, insurance, telecommunications and transport sectors.

Others are disappointed at the lack of a firm commitment to reducing protectionist barriers in industrialized countries to their exports of textiles and clothing. And most are manifestly unhappy that the European Community did not agree to demands for a liberalization of its agricultural trading policies.