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   41522篇
  免费   434篇
  国内免费   566篇
安全科学   1231篇
废物处理   1842篇
环保管理   5038篇
综合类   7846篇
基础理论   10723篇
环境理论   29篇
污染及防治   10605篇
评价与监测   2704篇
社会与环境   2239篇
灾害及防治   265篇
  2023年   211篇
  2022年   432篇
  2021年   415篇
  2020年   316篇
  2019年   378篇
  2018年   643篇
  2017年   616篇
  2016年   959篇
  2015年   734篇
  2014年   1117篇
  2013年   3186篇
  2012年   1388篇
  2011年   1836篇
  2010年   1516篇
  2009年   1602篇
  2008年   1867篇
  2007年   1915篇
  2006年   1644篇
  2005年   1450篇
  2004年   1288篇
  2003年   1392篇
  2002年   1237篇
  2001年   1597篇
  2000年   1141篇
  1999年   708篇
  1998年   483篇
  1997年   506篇
  1996年   494篇
  1995年   597篇
  1994年   613篇
  1993年   487篇
  1992年   486篇
  1991年   491篇
  1990年   520篇
  1989年   473篇
  1988年   409篇
  1987年   379篇
  1986年   327篇
  1985年   336篇
  1984年   348篇
  1983年   351篇
  1982年   337篇
  1981年   315篇
  1980年   270篇
  1979年   292篇
  1978年   249篇
  1977年   191篇
  1975年   202篇
  1972年   197篇
  1971年   185篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
931.
Environmental Science and Pollution Research - Copper (Cu) can be toxic to vegetables when it is absorbed and accumulated at large concentrations, a fact that increases the risk of excessive...  相似文献   
932.
Environmental Science and Pollution Research - Increasing ultraviolet (UV) radiation is causing oxidative stress that accounts for growth and yield losses in the present era of climate change....  相似文献   
933.
Environmental Science and Pollution Research - Exposure to environmental pollutants has been associated with alteration on relative levels of mitochondrial DNA copy number (mtDNAcn). However, the...  相似文献   
934.
Environmental Science and Pollution Research - The following work provides a perspective on the potential application of solar heterogeneous photocatalysis, which is a nonselective advanced...  相似文献   
935.
936.
Bound pesticide residues in soils: a review   总被引:34,自引:0,他引:34  
This article is a review of the current state of knowledge regarding the formation and biological/environmental significance of bound pesticide residues in soils. We begin by defining various terms used in our discussions and identifying the types/classes of pesticides which may be added to soil and interact with it. We then consider various soil properties and aspects of land management which will influence the nature and degree of the soil-pesticide association and discuss the possible physical and chemical binding mechanisms. We then move on to consider the role of microorganisms and other forms of soil biota in bound residue formation and the bioavailability of soil-borne pesticide residues. The review ends with a consideration of the significance of bound pesticide residues.  相似文献   
937.
This study represents a forensic chemical analysis to define the liability for the coastal bitumens polluting the beaches of the Mediterranean city of Alexandria. Six tar balls collected from several locations along the coast of the city were analyzed for their acyclic and polycyclic hydrocarbons as well as sulfur heterocycles using GC/FID, GC/AED and gas chromatography/mass spectrometry techniques. The analysis of one Egyptian crude oil is also included as a possible source oil. The tar ball samples were at early stages of weathering. Based on the GC traces and biomarker signatures, the tar balls could be genetically different. One sample collected from the Eastern Harbor region appears to be a Bunker C type fuel produced from Egyptian crudes. The refining process has removed the low molecular weight components. On the other hand, the wide n-alkane distribution together with the absence of an unresolved complex mixture suggests that crude oils probably from tank washings, ballast discharges or accident spills from tankers could have contributed significantly to the other tar ball samples. The distribution of source specific hopane and sterane markers revealed that the tar samples probably originate from different oil fields.  相似文献   
938.
In an effort to help with the development of effective dip vat management and waste disposal strategies this study determined how solution properties such as pH, buffer composition, ionic strength, temperature, solubility in organic solvents and the addition of commonly used solubilizing agents influenced the hydrolysis of amitraz. Amitraz degrade by means of hydrolysis described by a pseudo-first order rate process and a type ABCD pH rate profile. Hydrolysis increased with temperature and was fastest at low pH, slowest at neutral to slightly alkaline pH, and slightly increased above pH 10. However, buffer concentration and ionic strength influenced the hydrolysis rate and had to be accounted for before constructing a pH rate profile. Hydrolysis seems to depend on the dielectric constant of solvent mixtures and was fastest in water, slower in propylene glycol and ethanol solutions, and slowest in DMSO mixtures. In surfactant solutions, anionic micelles enhanced and cationic micelles retarded the hydrolysis rate. The magnitude of micellar effects decreased with increasing concentrations of the surfactants. The increased solubility and faster hydrolysis of amitraz in the sodium lauryl sulfate solutions showed that anionic surfactants potentially could be used for cleaning up amitraz spills, because it both solubilized the drug and catalyzed hydrolysis.  相似文献   
939.
With the help of a large number of monitoring sites, the behaviour of F in forested ecosystems of a formerly polluted area (M?hlin and Rheinfelden, Switzerland) could be studied over 30 years. An aluminium smelting plant originated the pollution of this area in the past: however, after the installation of a filtration plant in 1958 the F emissions were reduced and since 1991 almost absent the primary production of aluminium was stopped. The present-day area with elevated F contents (water-soluble F with >20 mg/kg) is restricted to a radius of about 1000 m from the plant. In 1969 this area had a radius of about 3 and 5 km. Between 1969 and 2000 a significant decrease in the soluble F content in the soil was observed together with a substantial decrease of F in the vegetation. The net losses of water-soluble F in the soil were in the range of 35 up to more than 70% of the original concentration and the F losses in the vegetation between 60 up to more than 80%. After the reduction of high F deposition rates the accumulated SOM was decomposed within the observation period 1969-1993. The combined decrease in F and humus led to chain reactions with losses of major elements and a dealumination of clay minerals, i.e. removal of interlayered Al of 2:1 minerals and consequent formation of smectites.  相似文献   
940.
Composts improve organic carbon content and nutrients of calcareous soils but the accumulation and distribution of phosphorus and heavy metals among various fractions in soil may vary under the south Florida conditions. The accumulation of P, Cd, Ni, and Pb with depth and the distribution of water soluble, exchangeable, carbonate, Fe-Mn oxides, organic and residual forms of each element were investigated in soils amended with municipal solid waste (MSW) compost, co-compost and biosolids compost and inorganic fertilizer (as control). Total concentrations of P, Cd, Ni, and Pb were higher in the 0-22 cm soil layers and decreased considerably in the rock layers. These elements were in the decreasing order of P > Pb > Ni > Cd. Amounts of water soluble and exchangeable forms of P, Cd, Ni and Pb were negligible at 0-22 cm soil depths except for Cd in the 10-22 cm depth. Amending calcareous soil with either organic or inorganic amendments rendered phosphorus, nickle and lead in the residual form followed by Fe-Mn oxides form in the 0-10 and 10-22 cm soil layers. Cadmium was predominantly in the Fe-Mn oxides fraction followed by the residual and carbonate forms in both soil layers. A significant positive correlation was found between various organic carbon fractions and organic forms of P, Cd and Pb in the surface soil layer. Soil amended with MSW compost had higher concentration of Cd in the organic fraction whereas, co-compost and MSW compost amended soil had higher concentrations of organic Ni fraction in the 0-10 cm soil layer.  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