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   185篇
  免费   1篇
安全科学   3篇
废物处理   7篇
环保管理   6篇
综合类   109篇
基础理论   25篇
污染及防治   26篇
评价与监测   5篇
社会与环境   5篇
  2019年   3篇
  2018年   3篇
  2016年   3篇
  2013年   4篇
  2011年   6篇
  2010年   3篇
  2009年   6篇
  2008年   6篇
  2007年   8篇
  2006年   3篇
  2005年   5篇
  2003年   7篇
  2002年   5篇
  2000年   5篇
  1999年   2篇
  1998年   2篇
  1997年   3篇
  1996年   5篇
  1995年   2篇
  1994年   3篇
  1991年   2篇
  1990年   3篇
  1989年   2篇
  1988年   2篇
  1986年   2篇
  1981年   2篇
  1980年   2篇
  1974年   2篇
  1969年   3篇
  1967年   3篇
  1965年   4篇
  1964年   2篇
  1963年   7篇
  1962年   8篇
  1961年   3篇
  1960年   3篇
  1959年   4篇
  1958年   4篇
  1957年   8篇
  1956年   5篇
  1954年   4篇
  1950年   2篇
  1940年   1篇
  1939年   2篇
  1938年   1篇
  1934年   1篇
  1932年   1篇
  1924年   1篇
  1920年   1篇
  1919年   2篇
排序方式: 共有186条查询结果,搜索用时 593 毫秒
81.
82.
83.
Karl H  Ruoff U  Blüthgen A 《Chemosphere》2002,49(7):765-773
In 1995-1998 the contents of polychlorinated dibenzodioxins and dibenzofurans of 184 pooled fish samples were analysed. Sampling focused on fish and fishery products with a market share of more than 1% and covered all fishing grounds important for the supply of the German market. Investigation included 15 different fish species, shrimp, mussel and squid samples and various fishery products, typically on the German market. Generally lean fish species like cod, saithe or Alaska pollock were less contaminated on fresh weight basis than fat fish species like herring, Greenland halibut and sardine. In herring the dioxin content is related to the fishing ground. Low concentrations were found in North Sea herring, high concentrations measured in samples from the Baltic Sea. Dioxin contents in fishery products did not differ significantly from the raw fish samples. Results allow an estimation of the daily intake of dioxins and furans via fish consumption in Germany. Based on a daily fish consumption of 20 g the average intake of dioxins via fish is 6.2 pg WHO-PCDD/F-TEQs per person and day.  相似文献   
84.
In this study the actual presence of the suspected endocrine disrupter Bisphenol A (BPA) in water systems was studied in the Netherlands. BPA was shown to be present in Dutch surface water at levels up to 330 ng/l, and one occasional observation of 21 microg/l. During the three sampling periods, 60-80% of the samples, most from marine and estuarine locations, contained BPA levels below the limit of quantification (14-40 ng/l). At a selected number of locations the presence of BPA in fish was studied, which showed that BPA varied from 2 to 75 ng/g in the liver and 1 to 11 ng/g in the muscle. Based on present measured concentrations in surface water and on literature derived toxicity data it was concluded that ecotoxicological effects nor estrogenic effects are likely to occur in the field situation.  相似文献   
85.
The fatty acid composition of 9 different tissues and organs of the female horseshoe crab Xiphosura (Limulus) polyphemus — one of the very few recent representatives of the ancient arthropod class Merostomata — was investigated in reference to the distribution of fatty acids through the marine food web. Fatty acid spectra, in which polyunsaturated fatty acids are predominant, especially eicosapentaenoic acid (20:5 3), revealed features characteristic of marine lipids. However, rather large quantities of monoenoic fatty acids also occur in all organs. In the saturated fatty acid fractions, the high content of branched-chain components is worth noticing, particularly in the gills and the carapace (35%); in all probability, the high amount of the branched-chain fatty acids is associated with their protective function in surface lipids. Isoprenoid fatty acids such as pristanic and phytanic acid were absent.  相似文献   
86.
87.
88.
89.
90.
Studies carried out in the NE coastal zone of the State of Pará (Brazil) have recorded, in the last 25 years, numerous evidence of natural impacts of the flood and erosion processes. As a consequence, diverse strategies and measures of population adaptation have been implemented but with limited success. Therefore, in order to subsidize the Coastal Zone Management Program of Pará, this paper aims to identify, assess and classify natural and socio-economic vulnerabilities of this coastal zone by means of a Geographical Information Systems (GIS)-based composite coastal vulnerability index (CVI). In spite of the data problems and shortcomings, using ESRI’s Arcview 3.2 program, the CVI score, to classify, weight and combine a number of 16 separate natural and socio-economic variables to create a single indicator provides a reliable measure of differences (5 classes) among regions and communities that are exposed to similar ranges of hazards. The results are presented in three maps referred to as Natural, Socioeconomic and Total Vulnerability. The confidence associated with the results obtained, the need to utilize another variables, and to frequently update the ones used already were analyzed and discussed.  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