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   2148篇
  免费   25篇
  国内免费   21篇
安全科学   42篇
废物处理   154篇
环保管理   191篇
综合类   264篇
基础理论   439篇
环境理论   3篇
污染及防治   717篇
评价与监测   226篇
社会与环境   150篇
灾害及防治   8篇
  2023年   38篇
  2022年   102篇
  2021年   119篇
  2020年   63篇
  2019年   44篇
  2018年   112篇
  2017年   106篇
  2016年   121篇
  2015年   75篇
  2014年   123篇
  2013年   205篇
  2012年   96篇
  2011年   141篇
  2010年   99篇
  2009年   97篇
  2008年   97篇
  2007年   106篇
  2006年   80篇
  2005年   67篇
  2004年   52篇
  2003年   47篇
  2002年   43篇
  2001年   30篇
  2000年   15篇
  1999年   13篇
  1998年   9篇
  1997年   9篇
  1996年   11篇
  1995年   5篇
  1994年   9篇
  1993年   5篇
  1992年   4篇
  1991年   7篇
  1990年   2篇
  1989年   2篇
  1988年   5篇
  1987年   4篇
  1986年   4篇
  1985年   3篇
  1983年   4篇
  1982年   2篇
  1968年   1篇
  1967年   1篇
  1964年   1篇
  1963年   1篇
  1959年   2篇
  1958年   1篇
  1956年   1篇
  1938年   1篇
  1915年   1篇
排序方式: 共有2194条查询结果,搜索用时 31 毫秒
931.
焦术木 《环境工程》1999,17(3):36-38
通过物理化学方法,研究治理与综合利用环氧丙烷生产中排放的高浓度氯气、有机氯化物废气的工艺,在小试、中试的基础上,确定了生产工艺条件和设备,并已投入实际运行,取得了令人满意的效果,开创了一条综合利用废气的新途径  相似文献   
932.
Concentration of Cd, Co, Cr, Ni, Zn, Fe, Mn, Pb and Cu were determinedin biota and sediment samples collected from the Marmara Sea in Turkey. The levels of Zn, Fe, Mn, Pb and Cu in the macroalgae are higher than previous studies in the Marmara Sea. Moreover, Cu and Zn concentrations at the present study are significantly high than Bosphorus and Black Sea algae. The order heavy metal concentrations in the mussel samples was: Fe > Zn > Ni > Mn > Cu > Pb > Cr > Cd > Co. The metal concentrations are generally lower when compared with the Black Sea mussels except Pb. At the same time, concentrations of Pb, Cu and Zn in the mussel species are lower when compared with the results in the Aegean Sea. The ranges of Mn and Cu in the tested fish samples are higher than Black Sea fish. On the other hand, Cd, Co, Cr, Zn and Pb concentrations are lower. The northern coast of the Marmara Sea having the highest metal concentrations in sediments as follows: Co, Cr, Ni, Fe at ?arköy ; Pb, Cu at M. Ere?li; Cd, Zn, Mn at Menek?e. The heavy metal levels in the sediment samples are lower than other areas in the Marmara Sea.  相似文献   
933.
Introduction to the problem of environmental pollution caused by acid depositions. Presentation of principles of the six-year field experiment with simulated acid rain. Short characteristics of particular parts of the series of papers.  相似文献   
934.
935.
Mitigation and Adaptation Strategies for Global Change - Global warming can intensify the soil organic matter (SOM) turnover, damaging soil health. Crop residues left on the soil are important to...  相似文献   
936.
This work is intended to show the characterization of three effluents (X, Y, and Z) derived from laboratory analyses conducted in the quality control department of a beneficiated bentonite products factory in order to present alternatives for their treatment and final disposal according to Brazil's National Solid Waste Policy (Política Nacional de Resíduos Sólidos – PNRS, Law 12,305/2010, Brazil). Analyses to identify the characteristics of the effluents revealed that the pH, salinity, electroconductivity, and total dissolved solids were in agreement with the organic and mineral nature of the effluent constituents: solvent, clay minerals, water, and activating agent. To assess reuse proposals, the effluents were subjected to the following tests: (a) swelling characteristic with effluent X, (b) petrochemical characterization of Y, and (c) swelling characteristic using commercial solvent and activated clay produced with effluent Z. Preliminary results indicate that each of these effluents can be reused variously in the laboratory, as a fuel, or in the original analysis/process.  相似文献   
937.
Regional Environmental Change - Avalanche risk changes through time due to climate, landscape and socio-environmental transformations. These drivers exhibit space-time variations as function of...  相似文献   
938.
Using a hand dredge, a population of Cassidulus mitis Krau, 1954 was sampled monthly from February 1986 to January 1987 at 15 stations offshore from Vermelha Beach (22°5718 S; 43°948 W), in water depths ranging from 0 to 6 m. The sex ratio indicated a slight numerical dominance of females for adults and a larger numerical female dominance for juveniles. A von Bertalanffy growth curve was estimated as L=71.00 (1-e(-0.390t)), where L=length (mm) and t=time (yr). The instantaneous natural mortality rate (M) was estimated as 0.812. The population occupies a zone parallel to the beach, and displays a spatially aggregated pattern, with higher densities in areas characterized by coarse and very well sorted sand containing low amounts of organic matter.  相似文献   
939.
Interest in renewable energy sources has increased in recent years due to environmental concerns about global warming and air pollution,reduced costs and improved efficiency of technologies.Under the European Union(EU)energy directive,biomass is a suitable renewable source.The aim of this study was to experimentally quantify and characterize the emission of particulate matter(PM_(2.5))resulting from the combustion of two biomass fuels(chipped residual biomass from pine and eucalypt),in a pilot-scale bubbling fluidized bed(BFB)combustor under distinct operating conditions.The variables evaluated were the stoichiometry and,in the case of eucalypt,the leaching of the fuel.The CO and PM_(2.5)emission factors were lower when the stoichiometry used in the experiments was higher(0.33±0.1 g CO/kg and 16.8±1.0 mg PM_(2.5)/kg,dry gases).The treatment of the fuel by leaching before its combustion has shown to promote higher PM_(2.5)emissions(55.2±2.5 mg/kg,as burned).Organic and elemental carbon represented 3.1 to 30 wt.% of the particle mass,while carbonate(CO_3~(2-))accounted for between 2.3 and 8.5 wt.%.The particulate mass was mainly composed of inorganic matter(71% to 86% of the PM_(2.5)mass).Compared to residential stoves,BFB combustion generated very high mass fractions of inorganic elements.Chloride was the water soluble ion in higher concentration in the PM_(2.5)emitted by the combustion of eucalypt,while calcium was the dominant water soluble ion in the case of pine.  相似文献   
940.
Aljustrel mines were classified as having high environmental hazard due to their large tailings volume and high metal concentrations in waters and sediments.To assess acid mine drainage impacted systems whose environmental conditions change quickly,the use of biological indicators with short generation time such as diatoms is advantageous.This study combined geochemical and diatom data,whose results were highlighted in 3 groups:Group 1,with low p H(1.9–5.1)and high metal/metalloid(Al,As,Cd,Co,Cu,Fe,Mn,Ni,Pb,Zn;0.65–1032 mg/L)and SO_4(405–39124 mg/L)concentrations.An acidophilic species,Pinnularia aljustrelica,was perfectly adapted to the adverse conditions;in contrast,teratological forms of Eunotia exigua were found,showing that metal toxicity affected this species.The low availability of metals/metalloids in sediments of this group indicates that metals/metalloids of the exchangeable fractions had been solubilized,which in fact enables metal/metalloid diatom uptake and consequently the occurrence of teratologies;Group 2,with sites of near neutral p H(5.0–6.8)and intermediate metal/metalloid(0.002–6 mg/L)and SO_4(302–2179 mg/L)concentrations;this enabled the existence of typical species of uncontaminated streams(Brachysira neglectissima,Achnanthidium minutissimum);Group 3,with samples from unimpacted sites,showing low metal/metalloid(0–0.8 mg/L)and SO_4(10–315 mg/L)concentrations,high pH(7.0–8.4)and Cl contents(10–2119 mg/L)and the presence of brackish to marine species(Entomoneis paludosa).For similar conditions of acidity,differences in diversity,abundance and teratologies of diatoms can be explained by the levels of metals/metalloids.  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