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   67篇
  免费   0篇
废物处理   5篇
环保管理   2篇
综合类   27篇
基础理论   18篇
污染及防治   14篇
评价与监测   1篇
  2021年   1篇
  2019年   1篇
  2018年   1篇
  2015年   1篇
  2014年   3篇
  2013年   3篇
  2011年   2篇
  2010年   2篇
  2009年   1篇
  2008年   2篇
  2007年   2篇
  2006年   3篇
  2005年   1篇
  2004年   2篇
  2003年   2篇
  2002年   1篇
  2001年   1篇
  1999年   2篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1994年   5篇
  1990年   5篇
  1989年   3篇
  1985年   1篇
  1979年   1篇
  1977年   2篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1972年   1篇
  1970年   1篇
  1968年   1篇
  1966年   2篇
  1965年   1篇
  1964年   1篇
  1962年   1篇
  1961年   1篇
  1960年   1篇
  1955年   1篇
  1930年   1篇
  1926年   1篇
排序方式: 共有67条查询结果,搜索用时 18 毫秒
31.
32.
We tested 19 sera from Austrian patients with acute hepatitis A. A serum from a 48-year-old female patient yielded HAV-nucleic acid that showed 99.7 % homology to the HAV-sequence obtained from samples taken during the current outbreak in several European countries, which is associated with consumption of frozen berries. So far, Austria was considered not to be affected by this hepatitis A outbreak.  相似文献   
33.
34.
Dynamics of colony development in Polistes dominulus: a modeling approach   总被引:1,自引:0,他引:1  
A simple model based on feedback mechanisms is developed to describe the dynamics of brood production and colony development of primitively eusocial paper wasps. The presence of pupae and empty cells stimulate egg laying, which varies between a basic rate and a physiological maximum. Newly hatched larvae are fed eggs, causing fluctuations in brood demography and forming cohorts of offspring. The basic feedback mechanisms produce emergent colony-level properties such as synchronized development of the brood and mature nest size. Results suggest that it is incorrect to imply colony decline from lack of nest growth, and that production of waves of offspring can be interpreted as the inevitable result of these simple feedback mechanisms rather than the solution to ultimate optimality criteria. Simulations using the parameters estimated in Polistes dominulus Christ are compared to studies of live wasps to test the validity of the model. Comparing simulated results with a perturbation experiment in nature suggests that feedback relationships establish a system that is robust and resilient against severe disturbance. Received: 20 January 1996/Accepted after revision: 27 April 1996  相似文献   
35.
Hriskova  K.  Marosevic  D.  Belting  A.  Wenzel  J. J.  Carl  A.  Katz  K. 《Food and environmental virology》2021,13(3):337-346
Food and Environmental Virology - In the last decade, the number of reported hepatitis E virus (HEV) infections in Germany, including Bavaria, has continued to rise. In order to identify risk...  相似文献   
36.
Two halophytes, Salicornia europaea and Atriplex verucifera, and the non-halophyte Chenopodium album were grown in pots on sodic and non-sodic Iranian soils spiked with up to 100 mg Cd kg?1. The halophytes grew best on the sodic soil in the absence of Cd spiking, while C. album performed better on non-sodic soil. Cadmium spiking reduced the growth of all plants, with Cd tolerance decreasing in the order S. europaea>A. verucifera>C. album. The observed order of Cd tolerance corresponds to the abilities of the plants to tolerate sodic soil properties. The variation of Cd concentration in shoots in response to sodicity was related to different mechanism, including dilution (C. album) Cd solubilisation by Ca2+ (S. europea) and Ca2+ competition for uptake and translocation of Cd (A. verucifera). Improved understanding of these complex interactions will help to design phytoextraction technology for Cd-polluted soils in arid regions.  相似文献   
37.
This study presents a detailed characterization of Shredder residues (SR) generated and deposited in Denmark from 1990 to 2010. It represents approximately 85% of total Danish SR. A comprehensive sampling, size fractionation and chemical analysis was carried out on entire samples as well as on each individual size fraction. All significant elemental contents except oxygen were analyzed. The unexplained “balance” was subsequently explained by oxygen content in metal oxides, carbonates, sulphates and in organics, mainly cellulose. Using mass and calorific balance approaches, it was possible to balance the composition and, thereby, estimate the degree of oxidation of elements including metals. This revealed that larger fractions (>10 mm, 10–4 mm, 4–1 mm) contain significant amount of valuable free metals for recovery. The fractionation revealed that the >10 mm coarse fraction was the largest amount of SR being 35–40% (w/w) with a metal content constituting about 4–9% of the total SR by weight and the <1 mm fine fraction constituted 27–37% (w/w) of the total weight. The lower heat value (LHV) of SR samples over different time periods (1990–2010) was between 7 and 17 MJ/kg, declining with decreasing particle size. The SR composition is greatly dependent on the applied shredding and post shredding processes at the shredding plants causing some variations. There are uncertainties related to sampling and preparation of samples for analyses due to its heterogeneous nature and uncertainties in the chemical analyses results (≈15–25%). This exhaustive characterization is believed to constitute hitherto the best data platform for assessing potential value and feasibility of further resource recovery from SR.  相似文献   
38.
Development and use of scenarios for large interdisciplinary projects is a complicated task. This article provides practical examples of how it has been carried out in two projects addressing waste management and energy issues respectively. Based on experiences from the two projects, recommendations are made for an approach concerning development of scenarios in projects dealing with both waste management and energy issues. Recommendations are given to develop and use overall scenarios for the project and leave room for sub-scenarios in parts of the project. Combining different types of scenarios is recommended, too, in order to adapt to the methods and tools of different disciplines, such as developing predictive scenarios with general equilibrium tools and analysing explorative scenarios with energy system analysis tools. Furthermore, as marginals identified in differing future background systems determine the outcomes of consequential life cycle assessments (LCAs), it is considered advisable to develop and use explorative external scenarios based on possible marginals as a framework for consequential LCAs. This approach is illustrated using an on-going Danish research project.  相似文献   
39.
40.
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