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   620篇
  免费   4篇
  国内免费   18篇
安全科学   8篇
废物处理   10篇
环保管理   33篇
综合类   229篇
基础理论   183篇
污染及防治   141篇
评价与监测   15篇
社会与环境   22篇
灾害及防治   1篇
  2018年   4篇
  2017年   8篇
  2016年   10篇
  2015年   12篇
  2014年   8篇
  2013年   27篇
  2012年   19篇
  2011年   27篇
  2010年   17篇
  2009年   16篇
  2008年   24篇
  2007年   33篇
  2006年   39篇
  2005年   25篇
  2004年   12篇
  2003年   18篇
  2002年   15篇
  2001年   16篇
  2000年   10篇
  1999年   20篇
  1998年   10篇
  1997年   12篇
  1996年   16篇
  1995年   13篇
  1994年   14篇
  1993年   8篇
  1992年   5篇
  1991年   4篇
  1989年   8篇
  1987年   4篇
  1985年   7篇
  1983年   7篇
  1981年   4篇
  1979年   4篇
  1973年   4篇
  1969年   4篇
  1966年   8篇
  1965年   4篇
  1964年   11篇
  1963年   11篇
  1961年   7篇
  1960年   10篇
  1958年   5篇
  1957年   8篇
  1956年   6篇
  1955年   6篇
  1954年   5篇
  1953年   7篇
  1950年   3篇
  1934年   3篇
排序方式: 共有642条查询结果,搜索用时 421 毫秒
461.
462.
463.
The gas-transport function of red blood cells which have incorporated inositol hexaphosphate is significantly improved by fusion with effector-loaded lipid vesicles. “Right-shifts” of the O2-binding curves of inositol hexaphosphate-loaded red blood cells with half-saturation pressures at 37 °C up to 98 mmHg are observed. The transformation of 56% of the intracellular haemoglobin into the low affinity state corresponds to an optimum increase of the O2-release capacity of 270%. The CO2 transport is also correspondingly enhanced. The treated red blood cells show no inositol hexaphosphate depletion during a reasonable time.  相似文献   
464.
465.
466.
467.
The EU is presently in a transition phase from environmental policy-making by law towards other governance approaches based upon networking, voluntary commitments, benchmarking and other forms of “soft law”. Those new governance approaches often claim to lead to “better regulation”, while adopting a more consensus-oriented and participatory style, taking economic aspects more seriously into account, allowing for more flexibility and autonomy for the private sector and Member States alike, mobilising a broader knowledge base or adopting more integrated and holistic approaches than previous sectoralised and compartmentalised policies.While the limitations of traditional regulatory approaches are widely accepted and cited, it is far from evident, that “new modes of governance” have greater capacity to solve problems than the old ones. There is an argument, that “better regulation” might by synonymous to a withdrawal and weakening of the regulatory state and hence effectively of the aspirations and objectives of environmental policies.An interesting case for an approach, combining the strengths of the old and the new approaches is the ongoing reform of chemicals policies. While some observers claim, that the proposed directive, “REACH” might belong to the outdated category of overcomplex and bureaucratic regulation, a closer look shows that there are many new forms of governance in REACH. This mixture or old and new may open a more realistic and promising perspective on the reform of European policy-making.In our paper we assess the effects and the interplay of the combination of different modes of governance using the example of REACH. We are particularly concerned with the question in how far the representation of interests may change when new modes of governance are introduced.  相似文献   
468.
469.
470.
Air pollution in the region Leipzig-Halle was investigated using two-year-old pine needles (Pinus sylvestris L.) at 39 sites of a biomonitoring net covering an area of ca. 7 500 km2. The concentration values of Al, Ca, Cr, Fe, K, Mg, Mn, Pb and V characterize the immission patterns of the period 1990/91. The method is less suited for Cu, Ni and Zn due to the transfer route soil-pine, and for Cd due to the small total content. There are significant spatial and element-specific variations which require distinct evaluation of the pollution situation. The city of Leipzig itself is a significant source for Pb, Cr, Fe and V emission. Mainly as far as the centre of the region is concerned, the Pb concentration values are beyond those of heavily contaminated reference sites. The bioindication system is also applicable for comparable regions in Eastern Europe where the pine is the dominating conifer type. Immission trends can be monitored over ecologically relevant periods of time.  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