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   4701篇
  免费   75篇
  国内免费   46篇
安全科学   148篇
废物处理   143篇
环保管理   703篇
综合类   1049篇
基础理论   1171篇
环境理论   9篇
污染及防治   1109篇
评价与监测   246篇
社会与环境   191篇
灾害及防治   53篇
  2023年   19篇
  2022年   26篇
  2021年   48篇
  2020年   27篇
  2019年   51篇
  2018年   106篇
  2017年   100篇
  2016年   110篇
  2015年   117篇
  2014年   125篇
  2013年   287篇
  2012年   198篇
  2011年   270篇
  2010年   204篇
  2009年   234篇
  2008年   244篇
  2007年   261篇
  2006年   245篇
  2005年   178篇
  2004年   153篇
  2003年   139篇
  2002年   159篇
  2001年   102篇
  2000年   82篇
  1999年   74篇
  1998年   61篇
  1997年   78篇
  1996年   62篇
  1995年   70篇
  1994年   60篇
  1993年   33篇
  1992年   42篇
  1991年   38篇
  1990年   33篇
  1989年   20篇
  1988年   18篇
  1986年   23篇
  1985年   18篇
  1984年   26篇
  1983年   25篇
  1982年   28篇
  1981年   22篇
  1980年   23篇
  1979年   33篇
  1978年   20篇
  1967年   17篇
  1965年   21篇
  1964年   18篇
  1961年   15篇
  1957年   15篇
排序方式: 共有4822条查询结果,搜索用时 31 毫秒
121.
Since 2005, a dramatic decline of the Arctic sea-ice extent is observed which results in an increase of shipping activities. Even though this provides commercial and social development opportunities, the resulting environmental impacts need to be investigated and monitored. In order to understand the impact of shipping in arctic areas, the method described in this paper determines the travel time, fuel consumption and resulting exhaust emissions of ships navigating in arctic waters. The investigated case studies are considering ship particulars as well as environmental conditions with special focus on ice scenarios. Travel time, fuel consumption and exhaust gas emission were investigated for three different vessels, using different passages of the Northern Sea Route (NSR) in different seasons of years 1960, 2000 and 2040. The presented results show the sensitivity of vessel performance and amount of exhaust emissions to optimize arctic traffic with respect to efficiency, safety and environmental impact.  相似文献   
122.
‘Bringing the state back in’ to research on comparative, inter-, and trans-national environmental politics and policy will contribute to better understanding of the limits and prospects of contemporary approaches to environmental politics and the overall evolution of contemporary states once environmental issues become central. The rationale for the state as an analytical perspective in environmental policy and politics is explained, and an empirically oriented concept of the environmental state is introduced, along with a tentative sketch of its evolution in historical perspective. A research agenda on the environmental state is mapped out, centring around variation and convergence in environmental states across space and time; the political/economic dynamics of contemporary environmental states; and inter-linkages among environmental problems, the constitution of political communities, and the functioning of the public power. In conclusion, the ways in which the contributions to this volume address that research agenda are introduced.  相似文献   
123.
124.
125.
Safety assessments for radioactive waste disposal require estimations of the migration of radionuclides in soils. The influence of humic acid (HA) on the sorption of uranium in its +4 oxidation state to kaolin has been examined from pH 4 to 8, with HA concentrations of 15–200 ppm. In the absence of HA, 20–40% of the U(IV) was in solution, with more sorption occurring at higher pH. The presence of HA solubilised up to 90% of the uranium with higher solubilities at higher HA concentrations and higher pH values. Uranium sorption was mapped against HA sorption, and it was found that there was a lower level of U(IV) sorption than can be accounted for by just measuring HA sorption. However, this effect got less marked as the pH rose. Sensitivity analysis indicated that the fraction of surface-bound HA is the controlling parameter for modelling in these systems.  相似文献   
126.
Environmental Science and Pollution Research - The scientific knowledge produced by academic research can be valued in all sectors of human activity, including private sector. The ROVALTAIN...  相似文献   
127.
Environmental Science and Pollution Research - We assessed the abundance of microplastics (0.2–5 mm) in drift line sediments from three sites in Kiel Fjord, Western Baltic...  相似文献   
128.

In this study, different pretreatment strategies of sugarcane bagasse prior to citric acid modification were investigated in terms of Pb2+ adsorption capacity. Pretreatment strategies included the use of NaOH, HCl, and C2H5OH in various concentrations. In order to fundamentally understand how these pretreatment methods affect the modification of sugarcane bagasse by citric acid as well as the Pb2+ adsorption capacity of sugarcane bagasse, three main components of sugarcane bagasse namely cellulose, hemicellulose, and lignin were isolated and esterified by citric acid under the same conditions. ATR-FTIR, XPS, SEM, and an analysis of the number of carboxylic acid groups were used to investigate the physicochemical and chemical properties of the materials. These three components were proved to participate in adsorption and induce the esterification with citric acid. Hence, pretreatment with ethanol and 0.01 M NaOH which could retain cellulose, hemicellulose, and lignin in sugarcane bagasse achieved a high Pb2+ adsorption capacity, i.e., 122.4 and 97 mg/g after the esterification with citric acid. In contrast, pretreatment with 0.5 M NaOH and 0.1 M HCl removed lignin and hemicellulose, leading to the lowest value of approximately 45 mg/g for citric acid esterified-pretreated sugarcane bagasse. XPS analysis and number of carboxylic group measurement confirmed the esterification between bagasse and citric acid. To understand the adsorption mechanism of adsorbent, two kinetic models including pseudo-first-order model and pseudo-second-order model were applied. The experimental data were well described by the pseudo-second-order model. The adsorption isotherm data were fitted Langmuir and Freundlich.

  相似文献   
129.
Environmental Science and Pollution Research - In this study, we compare the effects of deferiprone (Def) and tetraethylammonium salt of salinomycinic acid (Sal) on lead (Pb)-induced toxicity in...  相似文献   
130.
Environmental Science and Pollution Research - On-site small-scale sanitation is common in rural areas and areas without infrastructure, but the treatment of the collected fecal matter can be...  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