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   560篇
  免费   18篇
  国内免费   5篇
测绘学   31篇
大气科学   62篇
地球物理   147篇
地质学   154篇
海洋学   66篇
天文学   62篇
综合类   2篇
自然地理   59篇
  2022年   7篇
  2021年   11篇
  2020年   9篇
  2019年   9篇
  2018年   26篇
  2017年   12篇
  2016年   16篇
  2015年   11篇
  2014年   27篇
  2013年   33篇
  2012年   23篇
  2011年   31篇
  2010年   33篇
  2009年   41篇
  2008年   35篇
  2007年   31篇
  2006年   15篇
  2005年   17篇
  2004年   19篇
  2003年   14篇
  2002年   17篇
  2001年   8篇
  2000年   12篇
  1999年   13篇
  1998年   14篇
  1997年   7篇
  1996年   12篇
  1995年   9篇
  1994年   4篇
  1993年   6篇
  1991年   4篇
  1990年   2篇
  1985年   4篇
  1984年   4篇
  1983年   3篇
  1982年   2篇
  1981年   5篇
  1980年   2篇
  1979年   3篇
  1978年   3篇
  1977年   3篇
  1974年   3篇
  1971年   3篇
  1970年   4篇
  1958年   1篇
  1955年   1篇
  1952年   1篇
  1949年   1篇
  1943年   1篇
  1940年   1篇
排序方式: 共有583条查询结果,搜索用时 15 毫秒
581.
The ability of a large ensemble of regional climate models to accurately simulate heat waves at the regional scale of Europe was evaluated. Within the EURO-CORDEX project, several state-of-the art models, including non-hydrostatic meso-scale models, were run for an extended time period (20 years) at high resolution (12 km), over a large domain allowing for the first time the simultaneous representation of atmospheric phenomena over a large range of spatial scales. Eight models were run in this configuration, and thirteen models were run at a classical resolution of 50 km. The models were driven with the same boundary conditions, the ERA-Interim re-analysis, and except for one simulation, no observations were assimilated in the inner domain. Results, which are compared with daily temperature and precipitation observations (ECA&D and E-OBS data sets) show that, even forced by the same re-analysis, the ensemble exhibits a large spread. A preliminary analysis of the sources of spread, using in particular simulations of the same model with different parameterizations, shows that the simulation of hot temperature is primarily sensitive to the convection and the microphysics schemes, which affect incoming energy and the Bowen ratio. Further, most models exhibit an overestimation of summertime temperature extremes in Mediterranean regions and an underestimation over Scandinavia. Even after bias removal, the simulated heat wave events were found to be too persistent, but a higher resolution reduced this deficiency. The amplitude of events as well as the variability beyond the 90th percentile threshold were found to be too strong in almost all simulations and increasing resolution did not generally improve this deficiency. Resolution increase was also shown to induce large-scale 90th percentile warming or cooling for some models, with beneficial or detrimental effects on the overall biases. Even though full causality cannot be established on the basis of this evaluation work, the drivers of such regional differences were shown to be linked to changes in precipitation due to resolution changes, affecting the energy partitioning. Finally, the inter-annual sequence of hot summers over central/southern Europe was found to be fairly well simulated in most experiments despite an overestimation of the number of hot days and of the variability. The accurate simulation of inter-annual variability for a few models is independent of the model bias. This indicates that internal variability of high summer temperatures should not play a major role in controlling inter-annual variability. Despite some improvements, especially along coastlines, the analyses conducted here did not allow us to generally conclude that a higher resolution is clearly beneficial for a correct representation of heat waves by regional climate models. Even though local-scale feedbacks should be better represented at high resolution, combinations of parameterizations have to be improved or adapted accordingly.  相似文献   
582.
Abstract

This paper examines implementation of the Kyoto Protocol without Russia. It concludes that implementation without Russia is possible, although it requires political will on the part of the countries that wish to proceed with the Protocol. It would lead to higher compliance costs for Annex B buyer regions, but other regions, except Russia, would benefit financially. Russia would forego revenue of at least $20 billion for the first commitment period. Implementation without Russia could improve the environmental performance of the Protocol. It would reduce reliance on Annex B sinks, use of surplus assigned amount units (AAUs) for compliance, and the quantity of Kyoto units banked for subsequent commitment periods. Actual emissions by Kyoto Protocol Parties would fall, but the reduction may be offset by leakage to the US and Russia.  相似文献   
583.
A battery of biochemical biomarkers and the SigmaPCB concentration in adult female perch (Perca fluviatilis) verified an aquatic pollution gradient with the city of Stockholm (Sweden) as a point source of anthropogenic substances. The investigation included both an upstream gradient, 46 km westwards through Lake M?laren, and a downstream gradient, 84 km eastwards through the Stockholm archipelago. Besides the main gradient from Stockholm, there were strong indications of pollution coming from the Baltic Sea. The results indicated a severe pollution situation in central Stockholm, with poor health status of the perch, characterised by increased specific EROD activity in the liver, increased liver EROD somatic index, decreased AChE activity in the muscle, increased amount of DNA adducts in the liver, and a high concentration of biliary 1-pyrenol. In addition, laboratory exposure to common EROD inducers elicited an abnormal response, suggestive of chronic intoxication.  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