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   1859篇
  免费   9篇
  国内免费   2篇
安全科学   35篇
废物处理   59篇
环保管理   108篇
综合类   648篇
基础理论   317篇
环境理论   7篇
污染及防治   540篇
评价与监测   83篇
社会与环境   71篇
灾害及防治   2篇
  2021年   17篇
  2020年   13篇
  2019年   15篇
  2018年   31篇
  2017年   39篇
  2016年   38篇
  2015年   33篇
  2014年   46篇
  2013年   92篇
  2012年   37篇
  2011年   73篇
  2010年   52篇
  2009年   59篇
  2008年   90篇
  2007年   84篇
  2006年   68篇
  2005年   64篇
  2004年   40篇
  2003年   45篇
  2002年   45篇
  2001年   57篇
  2000年   38篇
  1999年   27篇
  1998年   17篇
  1997年   19篇
  1996年   17篇
  1995年   20篇
  1994年   30篇
  1993年   13篇
  1991年   15篇
  1984年   14篇
  1982年   12篇
  1981年   16篇
  1975年   12篇
  1974年   12篇
  1969年   14篇
  1968年   13篇
  1967年   15篇
  1966年   23篇
  1965年   29篇
  1964年   16篇
  1963年   25篇
  1962年   22篇
  1961年   30篇
  1960年   20篇
  1959年   22篇
  1958年   13篇
  1957年   24篇
  1956年   16篇
  1955年   16篇
排序方式: 共有1870条查询结果,搜索用时 125 毫秒
871.
Five species of Sepiola and Sepictta were reared in the laboratory from egg to adult size. Spawning was achieved in 3 species of Sepiola after 5 to 7 months. The growth rate of the species reared did not depend upon temperature, which ranged from 12.5° to 20°C. A fairly constant size increase (2.5 mm mantle length/month) was observed in Sepiola during the 5 months after hatching. In Sepietta, the same growth rate was observed until the fourth month after hatching, when it increased to the rate of 5 mm mantle length/month.Laboratoire associé au C.N.R.S.  相似文献   
872.
873.
874.
Green liquor dregs is the biggest waste fraction at sulphate pulp mills. It is commonly landfilled. Here we demonstrate that the utilization of green liquor dregs as a neutralizing agent for acidic wastewaters is a potential alternative and an environmentally friendly method in contrast to its landfill disposal. The liming effect value of 39.6% for green liquor dregs, expressed as Ca equivalent, is similar to the liming effect value of 38% of a commercial limestone product. In addition, the pH value of 10.7 indicates a strong liming effect.  相似文献   
875.
Summary. Host plant volatiles which attract insect herbivores for egg-laying are of principal interest with respect to insect ecology and evolution. Direct applications concern population monitoring and control through behavioural manipulation. Identification of behaviourally active plant secondary metabolites is essential also for plant breeding for insect resistance. Grapevine moth females Lobesia botrana are attracted by upwind flight to green grape berries Vitis vinifera. The headspace of grape berries was collected on air filters. A solvent extract of these filters, released from a sprayer, attracted females in the wind tunnel. The results demonstrate that volatile cues mediate attraction of grapevine moth females to grape berries, and that headspace collections capture the essence of this odour signal. The air filter extracts were examined by gas chromatography coupled with electroantennographic detection, and the compounds eliciting a consistent antennal response in L. botrana females were identified by mass spectrometry. The headspace collection apparatus was calibrated for collection efficiency of the active compounds. Their recovery rate ranged from 35 % for methyl salicylate to 83 % for (E,E)-α-farnesene. A synthetic ten-component blend was then formulated. The blend consisted of compounds eliciting an antennal response, formulated in a blend ratio corrected for differences in collection efficiency. Subsequent wind tunnel tests showed that female attraction to this synthetic ten-component blend was not significantly different from attraction to grape berries, or to headspace collections of the same berries. At a release rate of 35 ng/h of the most abundant compound (E)-β-caryophyllene, 20 % of the test females approached the source of sprayed headspace collections and the ten-component synthetic blend, respectively. In comparison, 100 g of green berries, releasing the main compound (E)-β-caryophyllene at a rate of ca. 4.7 ng/h, attracted 10 % of the females by upwind flight followed by source contact.  相似文献   
876.
Seven new dibenzylbutyrolactone and six new dibenzylbutanediol lignans were prepared to assist in the identification of a number of potential mammalian metabolites of the endocrine disrupting plant lignans syringaresinol and medioresinol, present in food.  相似文献   
877.
878.
879.
The combination of remote sensing methods like Doppler lidar and FTIR allows remote determination of mass fluxes of gases. Doppler lidar measures the three-dimensional wind vector in the vicinity of diffuse sources, or the velocity of air in a chimney plume if an industrial complex is monitored. FTIR is a multicomponent remote sensing method for gas concentrations. The Fourier transformation of an interferogram of a Michelson interferometer within a FTIR system converts the recorded intensity (function of optical path length) to a spectral signal (function of wavenumber). Both information, velocity and concentration, give the mass fluxes of the tracer (gas). A first test was performed at Munich-Nord power station with FTIR and cw-Doppler lidar. Fluxes of CO2, CO, NO, and HCl were determined. The results are in good agreement with the fluxes measured byin situ instruments of the power station. The method can be used to control industrial complexes from an outside observation site.  相似文献   
880.
ABSTRACT

Theory on participatory and collaborative governance maintains that learning is essential to achieve good environmental outcomes. Empirical research has mostly produced individual case studies, and reliable evidence on both antecedents and environmental outcomes of learning remains sparse. Given conceptual ambiguities in the literature, we define governance-related learning in a threefold way: learning as deliberation; as knowledge- and capacity-building; and as informing environmental outputs. We develop nine propositions that explain learning through factors characterizing governance process and context, and three propositions explaining environmental outcomes of learning. We test these propositions drawing on the ‘SCAPE’ database of 307 published case studies of environmental decision-making, using multiple regression models. Results show that learning in all three modes is explained to some extent by a combination of process- and context-related factors. Most factors matter for learning, but with stark differences across the three modes of learning, thus demonstrating the relevance of this differentiated approach. Learning modes build on one another: Deliberation is seen to explain both capacity building and informed outputs, while informed outputs are also explained by capacity building. Contrary to our expectations, none of the learning variables was found to significantly affect environmental outcomes when considered alongside the process- and context-related variables.  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