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   409篇
  免费   2篇
  国内免费   1篇
安全科学   2篇
废物处理   4篇
环保管理   9篇
综合类   214篇
基础理论   65篇
污染及防治   99篇
评价与监测   10篇
社会与环境   9篇
  2018年   4篇
  2016年   6篇
  2014年   8篇
  2013年   12篇
  2012年   8篇
  2011年   5篇
  2010年   13篇
  2009年   17篇
  2008年   9篇
  2007年   22篇
  2006年   9篇
  2005年   8篇
  2004年   9篇
  2003年   12篇
  2002年   14篇
  2001年   8篇
  2000年   8篇
  1999年   9篇
  1998年   7篇
  1997年   5篇
  1995年   6篇
  1994年   5篇
  1992年   5篇
  1983年   3篇
  1981年   4篇
  1978年   3篇
  1974年   3篇
  1973年   3篇
  1969年   3篇
  1967年   5篇
  1966年   8篇
  1965年   6篇
  1964年   8篇
  1963年   11篇
  1962年   4篇
  1961年   7篇
  1960年   5篇
  1959年   6篇
  1958年   10篇
  1957年   7篇
  1956年   7篇
  1955年   12篇
  1954年   6篇
  1952年   4篇
  1951年   3篇
  1950年   6篇
  1947年   5篇
  1943年   6篇
  1939年   4篇
  1924年   3篇
排序方式: 共有412条查询结果,搜索用时 0 毫秒
91.
Asexual propagation is an underappreciated way of increasing the sessile population of the metagenetic Scyphozoa. Our studies on Sanderia malayensis have shown a great variety of asexual reproduction modes. A new mode of polyp asexual propagation is described. By integrating earlier reported modes occurring in other species we established a classification which may serve as a standard tool to describe asexual propagation in Scyphozoa. The experiments performed comply with the current laws of Germany.  相似文献   
92.
The technique of diffusion gradient in thin films (DGT) for assessing bioavailable metals has not been tested under field conditions. We assessed the relationships of DGT- and cation exchange resin-membrane-measured concentrations of Cd, Cu, Pb, and Zn with plant uptake of the metals under greenhouse and field conditions. In the greenhouse, the effective concentrations of Cu, Pb, and Zn by DGT correlated significantly with uptake by sorghum (Sorghum bicolor), but cation exchange resin-membrane-measured concentrations of Cd, Pb, and Zn did not correlate with sorghum uptake. In the field, the DGT-measured concentrations of Cd, Pb, and Zn were not linearly related to uptake Cd, Pb, and Zn by lettuce (Lactuca sativa) except for Cu uptake (r = 0.87, p < 0.05). Similarly, it was only the resin-membrane-extractable Pb that correlated with Pb uptake by lettuce (r = 0.77; p < 0.05). However, fitting non-linear regression models improved the plant metal uptake predictions by DGT-measured bioavailable Cd, Cu, Pb, and Zn under field conditions. In conclusion, the DGT technique was fairly predictive of bioavailability in the greenhouse, but not in the field.  相似文献   
93.
The international, interdisciplinary biodiversity research project BIOTA AFRICA initiated a standardized biodiversity monitoring network along climatic gradients across the African continent. Due to an identified lack of adequate monitoring designs, BIOTA AFRICA developed and implemented the standardized BIOTA Biodiversity Observatories, that meet the following criteria (a) enable long-term monitoring of biodiversity, potential driving factors, and relevant indicators with adequate spatial and temporal resolution, (b) facilitate comparability of data generated within different ecosystems, (c) allow integration of many disciplines, (d) allow spatial up-scaling, and (e) be applicable within a network approach. A BIOTA Observatory encompasses an area of 1?km2 and is subdivided into 100 1-ha plots. For meeting the needs of sampling of different organism groups, the hectare plot is again subdivided into standardized subplots, whose sizes follow a geometric series. To allow for different sampling intensities but at the same time to characterize the whole square kilometer, the number of hectare plots to be sampled depends on the requirements of the respective discipline. A hierarchical ranking of the hectare plots ensures that all disciplines monitor as many hectare plots jointly as possible. The BIOTA Observatory design assures repeated, multidisciplinary standardized inventories of biodiversity and its environmental drivers, including options for spatial up- and downscaling and different sampling intensities. BIOTA Observatories have been installed along climatic and landscape gradients in Morocco, West Africa, and southern Africa. In regions with varying land use, several BIOTA Observatories are situated close to each other to analyze management effects.  相似文献   
94.
Environmental Science and Pollution Research - DDT transformation to DDD in soil is the most commonly reported pathway under anaerobic conditions. A few instances of DDT conversion to products...  相似文献   
95.
Ecological science contributes to solving a broad range of environmental problems. However, lack of ecological literacy in practice often limits application of this knowledge. In this paper, we highlight a critical but often overlooked demand on ecological literacy: to enable professionals of various careers to apply scientific knowledge when faced with environmental problems. Current university courses on ecology often fail to persuade students that ecological science provides important tools for environmental problem solving. We propose problem-based learning to improve the understanding of ecological science and its usefulness for real-world environmental issues that professionals in careers as diverse as engineering, public health, architecture, social sciences, or management will address. Courses should set clear learning objectives for cognitive skills they expect students to acquire. Thus, professionals in different fields will be enabled to improve environmental decision-making processes and to participate effectively in multidisciplinary work groups charged with tackling environmental issues.  相似文献   
96.
97.
98.
Lactate dehydrogenase is the prototype of an oligomeric, intracellular enzyme. Its primary, secondary tertiary, and quaternary structures are now well known. This fact, especially with regard to the occurrence of isoenzymes, has effected a great progress in the understanding of the structure-function relationship of enzymes. The historical development of modern enzymology is described, together with discussions of the various methods and problems of enzymology.  相似文献   
99.
100.
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