全文获取类型
收费全文 | 8633篇 |
免费 | 309篇 |
专业分类
8942篇 |
出版年
2020年 | 116篇 |
2019年 | 163篇 |
2018年 | 172篇 |
2017年 | 211篇 |
2016年 | 288篇 |
2015年 | 183篇 |
2014年 | 168篇 |
2013年 | 2187篇 |
2012年 | 213篇 |
2011年 | 260篇 |
2010年 | 236篇 |
2009年 | 211篇 |
2008年 | 204篇 |
2007年 | 172篇 |
2006年 | 164篇 |
2005年 | 113篇 |
2004年 | 114篇 |
2003年 | 105篇 |
2002年 | 114篇 |
2001年 | 126篇 |
2000年 | 136篇 |
1999年 | 172篇 |
1998年 | 114篇 |
1997年 | 77篇 |
1996年 | 89篇 |
1995年 | 94篇 |
1994年 | 91篇 |
1993年 | 94篇 |
1992年 | 97篇 |
1991年 | 76篇 |
1990年 | 75篇 |
1989年 | 79篇 |
1988年 | 85篇 |
1987年 | 92篇 |
1986年 | 88篇 |
1985年 | 122篇 |
1984年 | 121篇 |
1983年 | 129篇 |
1982年 | 99篇 |
1981年 | 104篇 |
1980年 | 107篇 |
1979年 | 102篇 |
1978年 | 94篇 |
1977年 | 108篇 |
1976年 | 86篇 |
1975年 | 95篇 |
1974年 | 84篇 |
1973年 | 80篇 |
1972年 | 62篇 |
1971年 | 66篇 |
排序方式: 共有8942条查询结果,搜索用时 15 毫秒
131.
Johnson JH 《Transactions (Institute of British Geographers : 1965)》1990,15(3):259-276
"A classic case where out-migration interacted with many other geographical phenomena is provided by rural Ireland in the nineteenth century. The apparent turning point was the Great Famine of the 1840s, but the areas with the greatest suffering from starvation did not necessarily show the greatest population decline, suggesting that other forces were active. Considerable economic and social changes were already taking place before the Famine: fertility was being reduced, later marriage was becoming established and considerable emigration was already taking place. Immediately after the Famine those areas which had been hardest hit often reverted to pre-Famine conditions and did not show strong population decline until the 1870s. The Famine was a most serious event, but the modernization of Irish rural life, which linked emigration with changes in family structure, agriculture and population numbers, was more important in bringing about geographical change." 相似文献
132.
133.
134.
135.
136.
Archaeometric analysis of ceramic production in Tiwanaku state (c.500–1000 ce): An exploratory study
J. P. Ogalde A. Korpisaari C. Riera‐Soto B. Arriaza C. Paipa P. Leyton M. Campos‐Vallette N. Lara J. Chacama 《Archaeometry》2021,63(1):53-67
The chemical and mineralogical characterization of seven ceramic fragments produced within Tiwanaku state (c.500–1000 ce ) is reported. The instrumental techniques used included X‐ray elemental and mineralogical chemical analysis, Raman spectroscopy, and scanning and light microscopy. The results indicate there are several clay types, although they show similarities, such as the use of a plant‐based temper. The red colour of the decoration is hematite, and manganese oxides such as jacobsite are present in the black. The white colour is a mixture of gypsum and clay, and the orange is a mixture of hematite and clay. The use of colours, the quality of the clays and the temperatures reached during pottery firing point to expertise in ceramic production and to complex decision‐making processes. The multi‐elemental archaeometric approach documented here could become an important tool to shed a light on ancient ceramic technology and the internal variance of Tiwanaku pottery. 相似文献
137.
F. Albarde J. Blichert‐Toft F. de Callataÿ G. Davis P. Debernardi L. Gentelli H. Gitler F. Kemmers S. Klein C. Malod‐Dognin J. Milot P. Tlouk M. Vaxevanopoulos K. Westner 《Archaeometry》2021,63(1):142-155
The reasons why the Western Mediterranean, especially Carthage and Rome, resisted monetization relative to the Eastern Mediterranean are still unclear. We address this question by combining lead (Pb) and silver (Ag) isotope abundances in silver coinage from the Aegean, Magna Graecia, Carthage and Roman Republic. The clear relationships observed between 109Ag/107Ag and 208Pb/206Pb reflect the mixing of silver ores or silver objects with Pb metal used for cupellation. The combined analysis of Ag and Pb isotopes reveals important information about the technology of smelting. The Greek world extracted Ag and Pb from associated ores, whereas, on the Iberian Peninsula, Carthaginians and Republican‐era Romans applied Phoenician cupellation techniques and added exotic Pb to Pb‐poor Ag ores. Massive Ag recupellation is observed in Rome during the Second Punic War. After defeating the Carthaginians and the Macedonians in the late second century bce , the Romans brought together the efficient, millennium‐old techniques of silver extraction of the Phoenicians, who considered this metal a simple commodity, with the monetization of the economy introduced by the Greeks. 相似文献
138.
Ruth J. Prince 《Anthropology today》2021,37(4):3-6
During fieldwork on cancer in Kisumu, western Kenya, the author slowly began, like those around her, to ask questions about its location and its temporalities, its beginnings and endings, its boundaries and entanglements with toxicants. In this article, the author describes the landscapes of exposure that people in western Kenya associate with an increasingly visible cancer epidemic, including concerns based on partial and tentative knowledge about the toxicity of foods. Starting from conversations about cancer, home, food and toxicity, she moves towards livelihoods, economies and ecologies, and the food and agricultural systems in which these exposures and uncertainties are embedded. 相似文献
139.
Hudson Mark J. Bausch Ilona R. Robbeets Martine Li Tao White J. Alyssa Gilaizeau Linda 《Journal of World Prehistory》2021,34(2):121-158
Journal of World Prehistory - From northern China, millet agriculture spread to Korea and the Maritime Russian Far East by 3500–2700 BC. While the expansion of agricultural societies across... 相似文献
140.
E. J. Fagan 《政策研究杂志》2023,51(2):243-263
This paper develops a theory of the relationship between policy disasters and political institutions. Policy disasters, defined as avoidable, unintended extreme negative policy outcomes, are important political, and historical events above that receive relatively little attention from political scientists and scholars of public policy. Using the predictions of punctuated equilibrium theory, I argue that systems with higher error accumulation will experience more policy disasters. Systems with more veto players and weaker information flows will experience more policy disasters, but information flows will have a stronger impact than veto players. I test this theory using data on financial crises and natural and technological disasters across 70 countries over 60 years. I find strong evidence that systems with weaker information flows and more veto players tend to have greater policy disaster risk. 相似文献