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   64篇
  免费   3篇
  国内免费   1篇
安全科学   4篇
废物处理   2篇
环保管理   8篇
综合类   17篇
基础理论   14篇
污染及防治   13篇
评价与监测   7篇
社会与环境   3篇
  2022年   2篇
  2021年   3篇
  2019年   1篇
  2018年   3篇
  2017年   5篇
  2016年   5篇
  2015年   4篇
  2014年   3篇
  2013年   4篇
  2012年   1篇
  2011年   7篇
  2010年   4篇
  2009年   6篇
  2008年   3篇
  2007年   2篇
  2006年   3篇
  2005年   1篇
  2004年   4篇
  2002年   1篇
  2001年   1篇
  1999年   1篇
  1995年   1篇
  1992年   1篇
  1989年   1篇
  1977年   1篇
排序方式: 共有68条查询结果,搜索用时 31 毫秒
11.
Monitoring of the ocean environment in southern California, USA, has been conducted by a diverse array of public and private organizations with different motivations, working on a variety of spatial and temporal scales. To create a basis from which to integrate information from these diverse programs, we conducted an inventory of ocean monitoring activities in the Southern California Bight to address the following questions: (1) How much money is being expended annually on marine monitoring programs? (2) Which organizations are conducting the most monitoring? (3) How are resources allocated among the different types of monitoring programs? This inventory focused on programs existing, or those expected to be in existence, for at least 10 years and that were active at any time between 1994 and 1997. For each program identified for inclusion in this study, information was collected on the number of sites, sampling intensity, parameters measured, and methods used. Levels of effort were translated into cost estimates based upon a market survey of local consulting firms. One hundred fourteen marine monitoring programs, conducted by 65 organizations and costing US $31 million annually, were identified. Most of the effort (81 programs, 65% of samples, 70% of costs) was expended by ocean dischargers as part of their compliance with National Pollutant Discharge Elimination System (NPDES) permit requirements. Federal programs (11 programs, 25% of samples, 10% of total expenditures) expended more than state or local government programs. More than one quarter of monitoring expenditures were conducted to measure concentrations and mass of effluent inputs to the ocean. The largest effort expended on receiving water monitoring was for measuring bacteria, followed by sediments, fish/shellfish, water quality, and intertidal habitats. The large level of expenditures by individual agencies has presented opportunities for integrating small, site-specific ocean monitoring programs into regional- and national-scale monitoring and assessment programs.  相似文献   
12.
Nanoparticles offer the potential to improve environmental treatment technologies due to their unique properties. Adsorption of metal ions (Pb(II), Cd(II), Cu(II), Zn(II)) to nanohematite was examined as a function of sorbent concentration, pH, temperature, and exhaustion. Adsorption experiments were conducted with 0.05, 0.1, and 0.5 g/L nanoparticles in a pH 8 solution and in spiked San Antonio tap water. The adsorption data showed the ability of nanohematite to remove Pb, Cd, Cu, and Zn species from solution with adsorption increasing as the nanoparticle concentration increased. At 0.5 g/L nanohematite, 100 % Pb species adsorbed, 94 % Cd species adsorbed, 89 % Cu species adsorbed and 100 % Zn species adsorbed. Adsorption kinetics for all metals tested was described by a pseudo second-order rate equation with lead having the fastest rate of adsorption. The effect of temperature on adsorption showed that Pb(II), Cu(II), and Cd(II) underwent an endothermic reaction, while Zn(II) underwent an exothermic reaction. The nanoparticles were able to simultaneously remove multiple metals species (Zn, Cd, Pb, and Cu) from both a pH 8 solution and spiked San Antonio tap water. Exhaustion experiments showed that at pH 8, exhaustion did not occur for the nanoparticles but adsorption does decrease for Cd, Cu, and Zn species but not Pb species. The strong adsorption coupled with the ability to simultaneously remove multiple metal ions offers a potential remediation method for the removal of metals from water.  相似文献   
13.
14.
15.
16.
火山灰的研究作为探讨古气候和古环境的一种手段,近十年来引起了国内外学者的广泛关注。气候学和古环境学的研究表明,火山喷发可以导致某一区域内短期的气候变化或者对冰期产生强烈影响。同时,火山灰层的成因机制决定了其空间分布的等时性和广泛性,因此,火山灰的地层学特征和精确定年,具有重要的地层对比意义。目前,全球各地已经开展了许多火山灰年代学与地层学的研究。在中国,尤其是东北地区,虽然有着丰富的火山资源,但是火山灰年代学与地层学的研究工作依然比较匮乏,本文简要回顾了一下中国东北、欧洲、新西兰、日本、俄罗斯等地区的火山灰研究工作,旨在为以后的研究提供一定的参考资料。  相似文献   
17.
18.
The textile industry is a favor to the Tunisian economy by offering several job positions. However, it’s not environmentally friendly. In fact, textile industries discharge high volumes of wastewater which contain several toxic pollutants such as dyes, fixator, and whiteness. In our study, Pseudomonas peli, isolated and characterized from Oued Hamdoun (center of Tunisia), was found able to decolorize textile effluent about 81 % after 24 h shaking incubation. On the other hand, the in vitro antiproliferative effects of the untreated and treated effluent was evaluated by their potential cytotoxic activity using the MTT colorimetric method against three human cancer cell lines (A549, lung cell carcinoma; HT29, colon adenocarcinoma; and MCF7, breast adenocarcinoma). Results showed that intact textile effluent and its content azo dyes didn’t inhibit the proliferation of all tested cell lines. However, the cytotoxic effect was remarkable when we tested effluent obtained after treatment by P. peli in a dose-dependent manner. This activity was attributed to the presence, in our treated effluent, of some azo products of dyes which are responsible for inhibition of human cell lines proliferation. Thus, the use of this strain for testing on the industrial scale seems impossible and disadvantageous.  相似文献   
19.
Environment, Development and Sustainability - The use of wastes for biogas production has been restricted to few feedstock like cattle manure and food waste. Increasing the feedstock base for...  相似文献   
20.
Reuse is generally considered to have environmental benefits, but it has not yet been widely adopted in environmental policy or strategy. In this paper, a simple model of second-hand markets is explored with a case study of used books that illustrates the behavior of the model and shows that such a model is consistent with the data. Three questions of the dynamics of reuse are addressed: (1) If it becomes easier to buy and sell used goods (via Internet markets or other means), by how much will sales of used goods increase? (2) When sales of used goods increase, by how much will sales of new goods decrease? (3) When is reuse better than recycling? Expanding from the case study, the model is used to examine how reuse affects the consumption of new goods, and the relative merits of reuse versus recycling. When the used goods market is small, the ratio of the price of used and new goods, an observable quantity, is approximately equal to the fractional decrease in sales of new goods that will result from increased sales of used goods. A formulation of the environmental impact of reuse and recycling is developed that includes the market impact of reuse. Illustrating this formulation for books with a simplified analysis, reuse of books through sales in a second-hand market is estimated to save more than twice as much energy, with considerable uncertainty, than making books from recycled paper. The formulation provides a basis for identifying products and markets for which reuse can be an effective environmental strategy.  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