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介绍了在曲柄压力机上切边冲孔的复合模结构设计、工作原理及装配和调试要求等. 相似文献
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Elias TS 《Science (New York, N.Y.)》1983,219(4580):19-23
In late 1972, the Soviet Union embarked on a program to identify and document plant species that are threatened with extinction. Perhaps 2000 species in the Soviet Union are in need of monitoring or protective measures, while nearly 200 may be in immediate danger of extinction. Currently, the Soviet Union has an official, national list of endangered species, and each of the 15 republics has prepared a regional list. Once a revised national list is prepared, Soviet scientists hope that the Supreme Soviet will pass a law protecting those species. A corresponding law for endangered animals was passed in 1980. 相似文献
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McKenna MC 《Science (New York, N.Y.)》1989,244(4908):1096-1097
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Amato I 《Science (New York, N.Y.)》1992,255(5050):1355