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   342篇
  免费   1篇
  国内免费   2篇
安全科学   5篇
废物处理   9篇
环保管理   15篇
综合类   52篇
基础理论   119篇
污染及防治   125篇
评价与监测   10篇
社会与环境   9篇
灾害及防治   1篇
  2022年   1篇
  2021年   2篇
  2018年   1篇
  2016年   2篇
  2015年   1篇
  2014年   3篇
  2013年   9篇
  2012年   10篇
  2011年   15篇
  2010年   11篇
  2009年   24篇
  2008年   14篇
  2007年   21篇
  2006年   20篇
  2005年   11篇
  2004年   9篇
  2003年   20篇
  2002年   11篇
  2001年   4篇
  2000年   18篇
  1999年   23篇
  1998年   16篇
  1997年   17篇
  1996年   17篇
  1995年   11篇
  1994年   8篇
  1993年   11篇
  1992年   3篇
  1991年   2篇
  1990年   3篇
  1989年   2篇
  1988年   2篇
  1987年   2篇
  1986年   1篇
  1983年   2篇
  1982年   1篇
  1981年   2篇
  1979年   2篇
  1978年   2篇
  1977年   1篇
  1968年   1篇
  1967年   2篇
  1965年   3篇
  1961年   1篇
  1959年   1篇
  1958年   1篇
  1955年   1篇
排序方式: 共有345条查询结果,搜索用时 296 毫秒
151.
The combination of remote sensing methods like Doppler lidar and FTIR allows remote determination of mass fluxes of gases. Doppler lidar measures the three-dimensional wind vector in the vicinity of diffuse sources, or the velocity of air in a chimney plume if an industrial complex is monitored. FTIR is a multicomponent remote sensing method for gas concentrations. The Fourier transformation of an interferogram of a Michelson interferometer within a FTIR system converts the recorded intensity (function of optical path length) to a spectral signal (function of wavenumber). Both information, velocity and concentration, give the mass fluxes of the tracer (gas). A first test was performed at Munich-Nord power station with FTIR and cw-Doppler lidar. Fluxes of CO2, CO, NO, and HCl were determined. The results are in good agreement with the fluxes measured byin situ instruments of the power station. The method can be used to control industrial complexes from an outside observation site.  相似文献   
152.
Various analyses and evaluative procedures are used to provide evidence of success using remediation procedures. Because of the lack of standardized procedures for soil assessment, general practice has unfortunately propagated the use of DIN standards for determining the level of similar parameters in water as well as for other heterogeneous matrices (e.g. in soil). A precise auditing of quality, however, has not been possible with this method, this procedure has even put the success of such a remediation into question. This article describes the problems of determining mineral hydrocarbon concentrations on soil as well as portraying the remediation of oil damages which has occurred on a site of a former waste oil redestillation facility [1, 2]. This procedure has been proved in practice and serves as a model because an adequately defined, standardized method (DIN standard) is lacking.  相似文献   
153.
154.
Ecotoxicological investigations focus on biological systems and their response to chemically induced stress. Experimental techniques are much more developed than deterministic dynamic modelling. In this methodological contribution a technique is presented, based on lattice theory. This technique, also calledHasse diagram technique, allows data analysis with respect to comparative evaluation. Hasse diagrams are used
  • ? to suggest a possible measure of microbial diversity,
  • ? to analyze dependencies between phospholipid fatty acids and simple geochemical parameters on an ordinal scale and
  • ? to visualise complex results of interactions of humic substances with xenobiotics.
  •   相似文献   
    155.
    In order to support evaluation and decision processes with respect to sustainability of management strategies, different mathematical methods can be applied. In this paper, the fundamentals of these so-called multi-criteria evaluation and decision-support instruments are presented. Moreover, advantages and disadvantages are worked out using an example data set of strategies of sustainable water management. It is shown that particularly transparency, objectivity and the degree of participation of stakeholders are the main characteristics: Whereas the Hasse diagram technique is directed to the scientifically given data matrix, and therefore yields an objective and transparent evaluation and data analysis, concordance analysis, utility function theory, PROMETHEE and AHP (analytical hierarchy process) have their preferences as participants or stakeholders in the decision process.  相似文献   
    156.
    Deponiegas     
    Investigations were performed concerning whether or not the composition of volatile halogenated carbons in landfill gas (LFG) change when they uncontrolledly leave the aerobic surface of landfill. For this reason, the aerobic biological degradation of chlorofluorocarbons (CFCs), chlorofluorohydrocarbons (HCFCs), and vinyl chloride (VC), which were often measured in LFG of old household-landfills, was investigated. In 1-liter and 126-liter laboratory test reactors, the aerobic milieu conditions of the surface of landfills were simulated. Air with methane and trichlorofluoromethane (R11), dichlorodifluoromethane (R12), and their reductive metabolites dichlorofluoromethane (R21), chlorodifluoromethane (R22), and vinyl chloride (VC) were continuosly pumped through marl and a mixture of biowaste and compost. R21, R22, and VC were degraded, probably cometabolically by methanotrophic bacteria. They have inhibited the methane oxidation. The degradation rates of R21 (only in biowaste and compost) and R22 were up to 2.8 and 10 mg/m3 material/h, respectively. The maximum degradation rate of VC was 1,3000 mg/m3 material/h in marl. Under aerobic milieu conditions, a biodegradation of R11 and R12 was not detected.  相似文献   
    157.
    158.
    159.
    The shores of many Central European lakes located in the hinterland of large conurbations are heavily endangered by intensive settlement, traffic, sewage input, manipulation of the water level, tourism and recreation. This increasing impact has negatively affected the function of the lake shore in respect to conservation and species protection, to water protection and its importance for recreation. This paper describes the overlap of the multiple uses and the precautions planned since 1981 on the national and international level to guarantee the essential multiple functionality, e.g. as drinking water reservoir for the conurbations in the northern part of Baden-Württemberg, as supraregional centre for water sports and tourism, and as an important environment for endangered plant and animal species. Management measures include regional planning as well as the international water protection and preservation with many contributions from non governmental international organisations. Given a high agreement concerning these aims, many indispensable actions could successfully be realised on the political and administrative level. On the basis of 14 topics we follow the development since 1981, most recently also driven by the EU (FFH Natura 2000, Water framework directive). Backlogs became obvious for four topics: 1. The lack of efficient reviews on completed measures, 2. gaps in basic understanding, 3. The dragging harmonisation of an integrated shore protection program across the borders, and 4. the lack of concepts for a sustainable development including plans for monitoring.  相似文献   
    160.
    In Nuremberg (Germany), each year about 25,000 tons (dry matter) of sewage sludge are obtained as by-product of waste water treatment. The digested sludge consists of 96% water. Until 1992 it was thermally stabilized using the Porteous procedure: the sludge was heated in an autoclave up to a temperature of 180–200 °C at a pressure of 28 bar. After pressure reduction and moving to a thickener, a substantial part of the liquid could be removed. After running through a chamber filter, the sludge contained only about 50% dry matter. This treatment does not only remove water; organic matter is also degraded or evaporated. Between November 1991 and May 1992, the sludge was analyzed four times before and after the drying process and examined for heavy metals (Pb, Cd, Cr, Cu, Ni, Hg, Zn), polychlorinated biphenyls (PCB) and PCDD/F. The concentration of heavy metals and PCB (related to dry matter) increased by a faktor of 1.3 after the drying process. This effect may be explained by the decrease of organic matter during drying. In the case of PCDD/F, the ITQ increased by a factor of 3.2, for some congeners even by a factor of 8. The only explanation can be that during thermal conditioning PCDD/F is formed by precursors as chlorophenols. This formation is probably catalyzed by metals as copper or nickel and sped up by the higher temperatures.  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