全文获取类型
收费全文 | 41184篇 |
免费 | 1555篇 |
专业分类
42739篇 |
出版年
2020年 | 523篇 |
2019年 | 816篇 |
2018年 | 908篇 |
2017年 | 1116篇 |
2016年 | 1200篇 |
2015年 | 926篇 |
2014年 | 904篇 |
2013年 | 14057篇 |
2012年 | 1048篇 |
2011年 | 1078篇 |
2010年 | 1061篇 |
2009年 | 1064篇 |
2008年 | 1004篇 |
2007年 | 912篇 |
2006年 | 817篇 |
2005年 | 564篇 |
2004年 | 560篇 |
2003年 | 521篇 |
2002年 | 496篇 |
2001年 | 478篇 |
2000年 | 428篇 |
1999年 | 496篇 |
1998年 | 446篇 |
1997年 | 417篇 |
1996年 | 395篇 |
1995年 | 409篇 |
1994年 | 352篇 |
1993年 | 401篇 |
1992年 | 380篇 |
1991年 | 291篇 |
1990年 | 289篇 |
1989年 | 297篇 |
1988年 | 300篇 |
1987年 | 313篇 |
1986年 | 288篇 |
1985年 | 409篇 |
1984年 | 436篇 |
1983年 | 444篇 |
1982年 | 381篇 |
1981年 | 384篇 |
1980年 | 417篇 |
1979年 | 412篇 |
1978年 | 395篇 |
1977年 | 418篇 |
1976年 | 372篇 |
1975年 | 377篇 |
1974年 | 288篇 |
1973年 | 262篇 |
1972年 | 240篇 |
1970年 | 222篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
231.
NORMAN A. GRAEBNER 《外交史》1987,11(4):337-354
232.
THE PALEOLITHIC CAVE ART OF VASCO-CANTABRIAN SPAIN 总被引:1,自引:0,他引:1
LAWRENCE G. STRAUS 《Oxford Journal of Archaeology》1987,6(2):149-163
Summary. This article explores the relationship between cave art and Upper Paleolithic archeology in northern Spain (and extreme southwestern France). Among the 83 known art sanctuaries, only three can probably be terminus ante quem dated to the early Upper Paleolithic (c. 35,000-20,000 BP). Other types of evidence (virtual absence of ornaments and mobile art objects before the Solutrean, stylistic similarities between works of late Upper Paleolithic mobile art and parietal art, overwhelming association of Solutrean and/or Magdalenian cultural deposits with art sanctuaries) clearly suggest that most of the cave art was done in the period between c. 20,000-10,000 BP. Cave art sanctuaries are distributed in non-random fashion. The clusters of sanctuaries usually correspond with dense clusters of habitation sites. The clusters are separated by substantial geographical gaps. These chronological and geographical facts coincide with contemporaneous subsistence intensification, all of which tends to support the hypothesis of increased territorialism in the late Last Glacial. 相似文献
233.
Anthony E. Marks 《African Archaeological Review》1987,5(1):79-92
Excavations by the joint University of Khartoum/Southern Methodist University Butana Project in the area just north of Khashm el Girba on the upper Atbara River have uncovered a series of preceramic and early ceramic occupations by hunters and gatherers which date fromca 10,000 bp toca 6200 bp. The earlier sites show no direct relations with those of similar age in the northern Sudan, while the later, early ceramic sites show only minor similarities with contemporary occurrences in the central Nile Valley. Thus, it appears that the upper Atbara River Valley played no role in the development of the Khartoum Mesolithic and that Nilotic influences were late reaching the eastern Sudan.
Résumé Des fouilles entreprises par le projet Butana dirigé en commun par l'université de Khartoum et le Southern Methodist University dans la région juste au nord de Khashm el Girba sur le cours supérieur de l'Atbara, ont découvert une série d'occupations précéramiques et céramiques anciennes de chasseurs-cueilleurs, qui datent deca 10,000 bp àca 6200 bp. Les gisements les plus anciens ne semblent pas avoir eu de relations directes avec ceux de la même période dans le nord du Soudan, tandis que les gisements plus tardifs à céramiques ne montrent que de petites analogies avec des occupations contemporaines dans la vallée centrale du Nil. Il semble donc que la haute vallée de l'Atbara n'a joué aucun rôle dans le développement du Mésolithique de Khartoum et que des influences nilotiques n'atteignirent que bien plus tard le Soudan oriental.相似文献
234.
235.
236.
237.
238.
Frederick C. Tiewes 《Australian Journal of International Affairs》1987,41(1):53-55
Harold Brown, Thinking about National Security: Defence and Foreign Policy in a Dangerous World. (Westview Press, Boulder, 1982.)
Seyom Brown, The Faces of Power Constancy and Change in United States Foreign Policy from Truman to Reagan. (Columbia University Press, New York, 1983.)
Zbigniew Brzezinski, Power and Principle: Memoirs of the National Security Adviser 1977–1981. (Farrar, Straus, Giroux, New York, 1983.)
Jimmy Carter, Keeping Faith: Memoirs of a President. (Bantam Books, New York, 1982.)
Cyrus Vance, Hard Choices: Critical Years in America's Foreign Policy. (Simon and Schuster, New York, 1983.) 相似文献
239.
The upper Mersey Valley was glaciated on three occasions during the Pleistocene. The youngest, Rowallan Claciation, probably commenced after 28000 years B.P. The maximum ice limit was attained before 13500 years B.P., and retreat occurred before 10000years B.P. Deposits associated with Rowallan Glaciation are weakly weathered chemically. They overlie moderately weathered deposits that were formed during the Arm Glaciation, which is inferred from relative dating data to have occurred before the Last Interglacial Stage. North of the deposits and ice limits of the Arm Glaciation extremely weathered tills and rhythmites occur. They were formed by ice of the Croesus Glaciation which is inferred to be of Early Pleistocene age or older. 相似文献
240.