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   291篇
  免费   0篇
  国内免费   8篇
安全科学   17篇
废物处理   10篇
环保管理   44篇
综合类   49篇
基础理论   53篇
污染及防治   84篇
评价与监测   20篇
社会与环境   19篇
灾害及防治   3篇
  2023年   8篇
  2022年   13篇
  2021年   18篇
  2020年   8篇
  2019年   4篇
  2018年   5篇
  2017年   9篇
  2016年   6篇
  2015年   7篇
  2014年   9篇
  2013年   36篇
  2012年   9篇
  2011年   12篇
  2010年   11篇
  2009年   14篇
  2008年   11篇
  2007年   15篇
  2006年   15篇
  2005年   12篇
  2004年   6篇
  2003年   10篇
  2002年   3篇
  2001年   1篇
  2000年   3篇
  1999年   3篇
  1998年   4篇
  1997年   2篇
  1996年   4篇
  1995年   1篇
  1994年   5篇
  1993年   3篇
  1992年   3篇
  1991年   1篇
  1990年   4篇
  1989年   4篇
  1987年   1篇
  1986年   4篇
  1985年   1篇
  1982年   3篇
  1981年   1篇
  1978年   1篇
  1973年   2篇
  1955年   1篇
  1938年   1篇
  1933年   1篇
  1931年   2篇
  1926年   1篇
  1920年   1篇
排序方式: 共有299条查询结果,搜索用时 15 毫秒
41.
ABSTRACT

Scholars and practitioners have focused in recent years on the potential for achieving cooperation in small “clubs” of countries. While solutions to global climate change will eventually require widespread cooperation, club strategies could help to catalyze that outcome. Unlike the Paris Agreement, which has achieved widespread but relatively shallow cooperation, it could be easier to tailor agreements that allow deep cooperation within smaller groups. This essay extends that logic to clubs whose geometry varies two-dimensionally across countries but also along a third dimension: within countries. Most of the key elements of international relations and international law theory that explain how clubs achieve cooperation are directly applicable to three-dimensional clubs. Most of the relevant experience for these clubs has occurred in the west; overdue is a close assessment of how key units – such as provinces and firms – within China and other emerging economies.  相似文献   
42.
Environmental Science and Pollution Research - Water is considered one of the most superabundant resources on the earth that covers 75% of the entire earth’s surface, yet numerous countries...  相似文献   
43.
The removal of heavy metals from wastewater has become a global challenge, which demands the continuous study of efficient and low-cost treatment alternatives such as adsorption. In this research, the removal of zinc was evaluated using batch adsorption processes with nonconventional materials such as graphene oxide (GO), magnetite (MG), and their composites (GO:MG), formulated with three weight ratios (2:1, 1:1, and 1:2). Graphene was synthesized by the modified Marcano method, using pencil lead graphite as a precursor. MG and the composites were synthesized by chemical coprecipitation of ferrous sulfate and ferric chloride. The materials were characterized by Raman and Fourier transform infrared spectroscopies, scanning electron microscopy, X-ray diffraction, and the Brunauer–Emmett–Teller method to determine the functional groups, microstructural and morphological characteristics, and specific surface area. Batch adsorption tests were carried out to optimize the adsorbent dose and contact time with zinc solutions of 10 ppm. Zinc adsorption reached equilibrium at 2 h, with an optimal dose between 0.25 and 1.0 g/L. The maximum zinc removal efficiencies/adsorption capacities were 98.6%/165.6, 83.4%/47.6, 83.5%/21.9, 72.8%/19.9, and 82.2%/9.25 mg/g using GO, 2GO:1MG, 1GO:1MG, 1GO:2MG, and MG, respectively. Furthermore, the analysis of the isotherm and adsorption kinetics models determined that the adsorption processes using MG and the composites fit the Sips and pseudo-second-order models.  相似文献   
44.
The chilled ammonia process absorbs the CO2 at low temperature (2–10 °C). The heat of absorption of carbon dioxide by ammonia is significantly lower than for amines. In addition, degradation problems can be avoided and a high carbon dioxide capacity is achieved. Hence, this process shows good perspectives for decreasing the heat requirement. However, a scientific understanding of the processes is required. The thermodynamic properties of the NH3–CO2–H2O system were described using the extended UNIQUAC electrolyte model developed by Thomsen and Rasmussen in a temperature range from 0 to 110 °C and pressure up to 100 bars. The results show that solid phases consisting of ammonium carbonate and bicarbonate are formed in the absorber. The heat requirements in the absorber and in the desorber have been studied. The enthalpy calculations show that a heat requirement for the desorber lower than 2 GJ/ton CO2 can be reached.  相似文献   
45.
The aim of the present study was to comparatively evaluate genomic damage (micronucleus) and cellular death (pyknosis, karyolysis, and karyorrhexis) in exfoliated oral mucosa cells from crack cocaine users by micronucleus test. A total of 30 crack cocaine users and 30 health controls (non-exposed individuals) were included in this setting. Individuals had epithelial cells from cheek mechanically exfoliated, placed in fixative, and dropped in clean slides, which were checked for the above nuclear phenotypes. The results pointed out significant statistical differences (p?<?0.05) of micronucleated oral mucosa cells from crack cocaine users. Exposure to crack cocaine caused an increase of other nuclear alterations closely related to cytotoxicity such as karyolysis in oral cells as well. In summary, these data indicate that crack cocaine is able to induce chromosomal breakage and cellular death in oral mucosa cells of users.  相似文献   
46.
This is the fourth in the series of Critical Reviews commissioned by the APCA Board of Directors. The first Critical Review "Regulations for the Control of Particulate and Sulfur Oxides Emissions" was published in 1974 and the topic is still timely. The second Critical Review "Regulations for the Control of Hydrocarbon Emissions (from Stationary Sources) and Odorous Pollutants" was published in 1975. In light of recent developments concerning hydrocarbon emissions from stationary sources, this Critical Review is again very timely. The third Critical Review "The Effect of Air Pollution Control Regulations on Land Use Planning" will soon be published in final form. Now we have the fourth in the series, "A Critical Review of Air Pollution Index Systems in the United States and Canada" and "Status Report on Federal Regulations for New Source Performance Standards".  相似文献   
47.
Aerosols of Serratia marcescens ATCC 274 were suspended in a 709L rotating drum at 20 ± 1 °C and high to mid-range relative humidities. At specified times after bacterial aerosolization, sulfur dioxide was added to concentrations of 2.5, or 5 mg/m3. Viable cell decay rate constants, in control aerosols without added sulfur dioxide, increased rapidly from near 100% to 60% RH in the first hour (termed: young aerosol) of suspension, and from a minimum rate constant at 80% in the succeeding four hours (termed: old aerosol).Upon addition of sulfur dioxide to a cloud of S. marcescens, generally, viable cell decay rate constants increased further. One exception was at 80% relative humidity where maximum resistance to SO2 accelerated death was observed for old aerosols. Cells in young aerosols were particularly sensitive to SO2 addition at mid-range humidities, while in older aerosols the cells were insensitive to up to 5 mg SO2/m3 introduced at high RH; but were up to 10 times more sensitive than cells in young aerosols to a given increase (from 2.5 to 5 mg/m3) in SO2 concentration at mid-range humidities.  相似文献   
48.
Environmental Science and Pollution Research - The rice husk ash (RHA) was used as an alternative source of silica for the synthesis of the functionalized mesoporous material, which was used in the...  相似文献   
49.
50.
A wide range of waste biomass/waste wood feedstocks abundantly available at mine sites provide the opportunity to produce biochars for cost-effective improvement of mine tailings and contaminated land at metal mines. In the present study, soft- and hardwood biochars derived from pine and jarrah woods at high temperature (700 °C) were characterized for their physiochemical properties including chemical components, electrical conductivity, pH, zeta potential, cation-exchange capacity (CEC), alkalinity, BET surface area and surface morphology. Evaluating and comparing these characteristics with available data from the literature have affirmed the strong dictation of precursor type on the physiochemical properties of the biochars. The pine and jarrah wood feedstocks are mainly different in their proportions of cellulose, hemicellulose and lignin, resulting in biochars with heterogeneous physiochemical properties. The hardwood jarrah biochar exhibits much higher microporosity, alkalinity and electrostatic capacity than the softwood pine. Correlation analysis and principal component analysis also show a good correlation between CEC–BET–alkalinity, and alkalinity–ash content. These comprehensive characterization and analysis results on biochars’ properties from feedstocks of hardwood (from forest land clearance at mine construction) and waste pine wood (from mining operations) will provide a good guide for tailoring biochar functionalities for remediating metal mine tailings. The relatively inert high-temperature biochars can be stored for a long term at mine closure after decades of operations.  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