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   88篇
  免费   0篇
废物处理   6篇
环保管理   4篇
综合类   49篇
基础理论   9篇
污染及防治   17篇
评价与监测   1篇
社会与环境   1篇
灾害及防治   1篇
  2022年   3篇
  2018年   1篇
  2016年   3篇
  2014年   2篇
  2013年   2篇
  2012年   3篇
  2011年   3篇
  2010年   4篇
  2009年   1篇
  2008年   2篇
  2005年   3篇
  2004年   2篇
  2001年   2篇
  1999年   2篇
  1998年   4篇
  1997年   1篇
  1995年   1篇
  1994年   2篇
  1993年   2篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1983年   1篇
  1982年   1篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
  1975年   1篇
  1974年   1篇
  1972年   1篇
  1969年   2篇
  1968年   1篇
  1967年   3篇
  1966年   4篇
  1965年   1篇
  1961年   2篇
  1959年   2篇
  1958年   2篇
  1957年   1篇
  1954年   3篇
  1953年   1篇
  1952年   1篇
  1951年   4篇
  1950年   1篇
  1947年   1篇
  1946年   1篇
  1942年   1篇
排序方式: 共有88条查询结果,搜索用时 203 毫秒
41.
42.
Rabbits have been suggested as a zoonotic source of Hepatitis E virus. Phylogenetic analysis of HEV isolates from farmed, wild and pet rabbits in the Netherlands (23, 0, and 60 % respectively) showed them to be grouped amongst published rabbit HEV sequences and distinct from most human isolates. Dutch rabbits are unlikely to be a zoonotic source.  相似文献   
43.
44.
In this study, the indicative value of mosses as biomonitors of atmospheric nitrogen (N) depositions and air concentrations on the one hand and site-specific and regional factors which explain best the total N concentration in mosses on the other hand were investigated for the first time at a European scale using correlation analyses. The analyses included data from mosses collected from 2781 sites across Europe within the framework of the European moss survey 2005/6, which was coordinated by the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops (ICP Vegetation). Modelled atmospheric N deposition and air concentration data were calculated using the Unified EMEP Model of the European Monitoring and Evaluation Programme (EMEP) of the Convention on Long-range Transboundary Air Pollution (CLRTAP). The modelled deposition and concentration data encompass various N compounds. In order to assess the correlations between moss tissue total N concentrations and the chosen predictors, Spearman rank correlation analysis and Classification and Regression Trees (CART) were applied. The Spearman rank correlation analysis showed that the total N concentration in mosses and modelled N depositions and air concentrations are significantly correlated (0.53 ≤ rs ≤ 0.68, p < 0.001). Correlations with other predictors were lower than 0.55. The CART analysis indicated that the variation in the total N concentration in mosses was best explained by the variation in NH4+ concentrations in air, followed by NO2 concentrations in air, sampled moss species and total dry N deposition. The total N concentrations in mosses mirror land use-related atmospheric concentrations and depositions of N across Europe. In addition to already proven associations to measured N deposition on a local scale the study at hand gives a scientific prove on the association of N concentration in mosses and modelled deposition at the European scale.  相似文献   
45.
10 years ago, the WWF (World Wide Fund for Nature) began to support the work of environmental protection in the countries of Eastern Europe. A main topic is the Danube-Carpathian Program. With the beginning of the bombardements, connected with great amounts of chemicals released directly and as clouds from the fires and explosions, the question raises: What are the consequences for mankind and nature? Is there a risk for the Danube-Carpathian Program? The WWF feels responsible for reporting about these consequences. In July 1999, a group of two Oil Experts and two scientists (each a chemist and a toxicologist) visited Belgrad, Pan?evo and Novi Sad, took samples of soil and water, and estimated the contents of dangerous substances. The first findings and the first consequences for nature and human health are described.  相似文献   
46.
This study aimed at cross-border mapping metal loads in mosses in eight European countries in 1990, 1995, and 2000 and at investigating confounding factors. Geostatistics was used for mapping, indicating high local variances but clear spatial autocorrelations. Inference statistics identified differences of metal concentrations in mosses on both sides of the national borders. However, geostatistical analyses did not ascertain discontinuities of metal concentrations in mosses at national borders due to sample analysis in different laboratories applying a range of analytical techniques. Applying Classification and Regression Trees (CART) to the German moss data as an example, the local variation in metal concentrations in mosses were proved to depend mostly on different moss species, potential local emission sources, canopy drip and precipitation.  相似文献   
47.
48.
To determine whether a population has been affected by a chemical, evidence of exposure must be established. The mere presence of a chemical in the surroundings of a population may not, in all instances, result in actual exposure. Not all such exposures will cause health effects; nor is it always possible to establish that illness has or will result from exposure to chemicals. The inability to establish health effects in humans cannot a priori be translated to mean that a specific chemical is harmless. On the other hand, it must be determined whether health studies would be fruitful. If exposure was so minimal that no health effects are expected, then no health studies should be conducted.  相似文献   
49.
50.
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