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   171篇
  免费   15篇
  国内免费   11篇
测绘学   11篇
大气科学   34篇
地球物理   63篇
地质学   12篇
海洋学   14篇
天文学   52篇
综合类   3篇
自然地理   8篇
  2023年   6篇
  2022年   1篇
  2021年   1篇
  2020年   4篇
  2019年   7篇
  2018年   3篇
  2017年   3篇
  2016年   5篇
  2015年   5篇
  2014年   5篇
  2013年   16篇
  2012年   4篇
  2011年   6篇
  2010年   7篇
  2009年   6篇
  2008年   12篇
  2007年   7篇
  2006年   10篇
  2005年   9篇
  2004年   7篇
  2003年   6篇
  2002年   11篇
  2001年   2篇
  2000年   19篇
  1999年   17篇
  1998年   8篇
  1996年   1篇
  1994年   1篇
  1991年   1篇
  1990年   1篇
  1988年   4篇
  1986年   1篇
  1983年   1篇
排序方式: 共有197条查询结果,搜索用时 15 毫秒
81.
《Climate Policy》2013,13(1):22-39
Despite the importance of emissions trading and energy taxes to the EU and national climate strategies, limited research exists on their impact on emissions from the perspective of industry sectors targeted by economic instruments. This article contributes to redressing this deficit by critically analysing whether economic instruments applied within the UK provide sufficiently strong price incentives to overcome barriers to investment in energy-intensive sectors created by the capital and finance costs of replacing ‘legacy’ infrastructure and fluctuating base energy prices. Results from a survey of 189 companies from the cement, aluminium and chemicals sectors and 23 interviews with sector associations and businesses from these and other energy-intensive industries indicate that economic instruments have raised awareness of energy efficiency but have had a minimal impact on investment decisions. EU-wide economic instruments such as the EU emissions trading scheme have yet to be fully tested but may encounter similar difficulties. On this basis, we argue that economic instruments may need to be complemented by more interventionist programmes focusing on large-scale investment in energy modernization and we also discuss how economic instruments can contribute to this agenda.  相似文献   
82.
《Climate Policy》2013,13(6):548-568
In contrast to the federal government, some US states have taken an aggressive approach to curbing climate change. They use a variety of policy instruments to reduce greenhouse gases. These instruments can be categorized into two broad categories: economic incentives and command-and-control regulation. While the use of economic incentives has, on average, increased, some states employ them more than others. This article compares the propensity of different US states to employ economic incentives in the area of climate change. For this purpose, it analyses and tests four models: (i) a needs/responsiveness model, (ii) an interest group influence model, (iii) an innovation-and-diffusion model, and (iv) a combined model. Interestingly, this article finds that economic incentives are pushed out of the political agenda when states are confronted with a more severe problem in terms of carbon emissions and dependence on conventional energy. This article also finds support for the traditional, antagonistic view of ‘industry versus environmentalists’: electric utility companies tend to oppose economic incentives, while environmentalists and renewable energy producers tend to support them.  相似文献   
83.
84.
东亚金融危机与中国   总被引:1,自引:1,他引:0  
经历时间长、影响范围广的东亚金融危机是由多方面的原因造成的。它的基础是广泛存在的泡沫经济。金融业的全球一体化,离岸金融中心和金融衍生工具的出现,国际炒家的掀风作浪,加剧了危机的深度。中国由于实质经济比较稳固,对金融业开放持谨慎态度等原因,受到的冲击相对较小。危机给中国敲响了警钟,要求中国尽快进行金融体制的改革。  相似文献   
85.
The satellite INTERBALL-2 has an orbit with high inclination (62.8°), covering the altitude range between a few hundred and about 20000 km. The ambient plasma conditions along this orbit are highly variable, and the interactions of this plasma with the spacecraft body as well as the photo-electron sheath around it are considered to be interesting topics for detailed studies. The electric potential of the spacecraft with respect to the ambient plasma that develops as a result of the current equilibrium reacts sensitively to variations of the boundary conditions. The measurement and eventual control of this potential is a prerequisite for accurate measurements of the thermal plasma. We describe the purpose and technical implementation of an ion emitter instrument on-board INTERBALL-2 utilising ion beams at energies of several thousand electron volts in order to reduce and stabilise the positive spacecraft potential. First results of the active ion beam experiments, and other measures taken on INTERBALL-2 to reduce charging are presented. Furthermore, the approach and initial steps of modelling efforts of the sheath in the vicinity of the INTERBALL-2 spacecraft are described together with some estimates on the resulting spacecraft potential, and effects on thermal ion measurements. It is concluded that even moderate spacecraft potentials as are commonly observed on-board INTERBALL-2 can significantly distort the measurements of ion distribution functions, especially in the presence of strongly aniso-tropic distributions.  相似文献   
86.
中国地球物理仪器和实验设备研究与研制的发展与导向   总被引:30,自引:20,他引:10       下载免费PDF全文
地球物理学本质上是一门观测的科学.高精度和高分辨率的观测与实验仪器和设备乃是在地球物理学发展进程中的“前哨”.为此,在我国地球物理学领域里,在对仪器和设备的研究中必须转变观念,即在引进技术,仿造和合作研制的基点上发展自己的研究与研制体系,并在不断深化的进程中,逐步开创中国地球物理仪器研究和研制的新局面,形成具有中国特色的,并具有独立主权和品牌的地球物理仪器及设备的创新研究和研制体制,进而开拓新市场,走向世界,并独立于世界科技之林.  相似文献   
87.
Guifang Xue 《Marine Policy》2006,30(6):651-658
The paper discusses China's policy adjustment responding to flag state responsibilities of the Fish Stocks Agreement and the Compliance Agreement. China's incorporation and application of the management measures of the two instruments into its domestic legislations regarding distant water fishing vessels is examined to illustrate China's compliance as a flag state. It will be shown that China has taken concrete steps to bring its management practice in line with the requirements of international fisheries instruments and has endeavoured to respond to the two instruments positively. However, China needs to set priorities to improve its overall management capacity so as to make it ready to ratify the two instruments and to live up to their terms.  相似文献   
88.
地形图等高线的测绘方法   总被引:2,自引:0,他引:2  
等高线是地形图的重要元素,本文详细介绍等高线的特征,以及测绘地形图等高线的过程和方法.通过对航空摄影测量中几种测绘等高线的方法进行比较.总结出利用全数字摄影测量系统配合其他软件测绘等高线的方法不但精度高,而且实用快捷.  相似文献   
89.
精密工程测量领域,对仪器有着极高的要求,需要定期对仪器的各项性能指标进行检定。仪器的检定和精度标定都需要有一定的基准,并用来评价仪器的性能。文中以球体为基准建立空间标定场,提出利用TLS(整体最小二乘平差)算法拟合球面的方法,并对比分析该方法的可行性;提出在满足精度要求下,参考球的选择方法;理论加实例分析,验证该方法的合理性。  相似文献   
90.
随着海洋仪器在海洋调查、海洋监测、海洋科研等领域的广泛应用,开展海洋仪器的计量检定校准工作成为了国家海洋计量站最基本的业务工作之一。“海洋仪器计量检定校准数据处理系统”是专门为海洋仪器计量检定、校准数据的处理而设计的软件系统,文章详细介绍了该系统的结构和功能。  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