首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3379篇
  免费   120篇
  2020年   45篇
  2019年   59篇
  2018年   77篇
  2017年   76篇
  2016年   94篇
  2015年   67篇
  2014年   59篇
  2013年   1096篇
  2012年   74篇
  2011年   86篇
  2010年   76篇
  2009年   74篇
  2008年   75篇
  2007年   56篇
  2006年   59篇
  2005年   40篇
  2004年   36篇
  2003年   31篇
  2002年   45篇
  2001年   50篇
  2000年   28篇
  1999年   43篇
  1998年   22篇
  1997年   31篇
  1996年   26篇
  1995年   22篇
  1994年   38篇
  1993年   32篇
  1992年   34篇
  1991年   21篇
  1990年   32篇
  1989年   28篇
  1988年   30篇
  1987年   32篇
  1986年   30篇
  1985年   33篇
  1984年   52篇
  1983年   54篇
  1982年   47篇
  1981年   38篇
  1980年   34篇
  1979年   41篇
  1978年   42篇
  1977年   30篇
  1976年   32篇
  1975年   34篇
  1973年   27篇
  1972年   31篇
  1971年   21篇
  1970年   32篇
排序方式: 共有3499条查询结果,搜索用时 218 毫秒
81.
Geological processes are fundamental to the understanding of Global Change and the geological record provides a baseline against which to assess the nature and significance of contemporary global change (Price 1986)  相似文献   
82.
On March 11, 1989, twenty-four governments called for the development, within the framework of the United Nations, of
new institutional authority, either by strengthening existing institutions or by creating a new institution which, in the context of the preservation of the earth's atmosphere, shall be responsible for combating any further global warming of the atmosphere. (Declaration of The Hague, 1989. p. 1308)  相似文献   
83.
ABSTRACT. Nearly all regional input-output models have been constructed without a proper accounting of inflows and outflows of personal income and personal consumption expenditures. Typically invoked is a no cross-payments assumption, analogous to the no cross-hauling assumption for commodities. We present a new accounting framework based on the classification of flows according to the location of income generation, receipt, and spending, and argue that only flows endogenous in all three respects should be part of a closed regional I-O model. We use the framework to compute the upward bias in multipliers in a typical regional I-O model. We also present several methods for estimating transboundary flows.  相似文献   
84.
85.
86.
87.
By 1980, the Brasilian steel industry had grown to be the eighth largest among the market economies. It is a largely state-owned industry, much of the expansion of which has been funded by international capital. The pattern of development has not been externally imposed, however, but rather reflects the changing balance of class forces within Brasil as policies oscillate between nationalist, populist limits on foreign investment and open, pro-development strategies that rely on foreign investment. Both policies develop their own contradictions, that are reflected in frequent military interventions.  相似文献   
88.
"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   
89.
90.
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   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号