House-Senate conferees failed yesterday in a last-ditch effort to save legislation that gives the president authority to control strategic exports to Soviet bloc nations.

Meanwhile, Congress gave final approval yesterday to a comprehensive international trade bill that extends until 1993 tariff concessions to 140 poor countries and authorizes the president to negotiate with Israel the United States' first full free-trade arrangement. The measure, a compromise of House and Senate versions, was approved 386 to 1 in the House, with only Rep. Philip M. Crane (R-Ill.) dissenting. The Senate then passed it by voice vote and sent it to President Reagan for his signature.

In the export controls effort, the conferees tried to forge a compromise that eliminated two major provisons from a bill extending and revising the Export Administration Act -- one disliked by the House, the other by the Senate.

Under the compromise, the Senate would have dropped its insistence of increasing the Pentagon's role in export licensing, while the House would have given up a ban on bank loans to South Africa.

It is unclear whether either the Senate or the House will try to pass legisislation simply extending the Export Administration Act, which expired Sept. 30. Without any EAA legislation to control strategic exports, the president must rely on the International Emergency Economic Powers Act, which some trade lawyers believe is open to court challenges.