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101.
用固体力学化学理论研究岩土的力学化学行为——以成都龙泉紫色土为例 总被引:1,自引:0,他引:1
根据固体力学化学理论 ,提出用化学动力学方法研究岩土破坏及滑坡形成的机理 ,并以成都龙泉紫色土为例研究了在力与水协同作用下易滑土层的力学化学行为。实验表明 ,土长期抗剪强度降低的幅度与溶液的pH值有关 ,土的溶解速度与易溶盐含量有关 ,且溶解曲线略呈“S”型。这初步证明了龙泉紫色土破坏的力学 化学效应及其可能存在的自催化趋势。通过实验了解了力与水协同作用导致土破坏的力学化学规律 ,并将定量求解滑面长期抗剪强度与反应机理研究结合起来 ,为定量评价地下水和应力对岩土破坏机理这一滑坡学关键问题打下基础。 相似文献
102.
计算流体力学(CFD)中的迭代法及其并行计算方法 总被引:2,自引:0,他引:2
应用计算流体力学 (CFD)方法分析事故原因已被广泛采用 ,笔者针对事故理论分析和流体计算过程中 ,运用CFD方法所存在计算量大的问题 ,分析和讨论了几种古典迭代法及其并行计算方法 相似文献
103.
104.
喀斯特石山地区社会经济与生态环境可持续发展系统研究:以桂西北为例 总被引:5,自引:0,他引:5
本建立了广西西北部喀斯特石山地区可持续发展的系统动力学模型。并用DYNAMO程序预测了未来20年桂西北地区的人口、工业、农业、第三产业,生态环境,土地资源,社会总产值,人均国民收人等的动态变化趋势,结果显示,该地区由于人口,工业资产增加使物质和能源消耗增长太快,而对污染治理的投入又太少,导致桂西北地区的生存环境质量下降,因此应当加大对污染治理的投入力度,改善区域环境质量,这是实现息烽县区域可持续发展的关键,根据区域特点探讨了桂西北喀斯特贫困山区的形成演化,提出了可持续发展的途径。 相似文献
105.
For about 50 years the desertion of areas by traditional activities has led to an important evolution of landscapes and environments
on the island of Ouessant. The study of this evolution has been undertaken at different spatial and temporal scales. On one
part of the island, a scientific investigation carried out at the scale of the parcel enabled the form of the landscape in
1850 to be compared with that of 1985. On the whole island, the evolution of spatial organization and land use was compared
between 1950 and 1985. For each of three main ecological environments, vegetational successions after the decrease of agriculture
have been studied along with their future potential changes. This work highlights some considerations about the present management
of the environment in relation to the major objectives of island environmental policies. 相似文献
106.
大气中SO2的液相氧化研究 总被引:2,自引:0,他引:2
大气中SO2液相氧化是形成酸雨的重要途径,降雨中含有各种无机离子和有机物质,它们可能催化或抑制液相氧化反应的进行。本文根据四川酸雨样品组成,进行了SO2在模拟雨水及实际雨水中的氧化实验,考查了V,Fe,Mn等离子对SO2氧化的催化作用,H2O2对SO2的氧化以及降水中有机物质甲醛对各反应的影响。实验结果为了解酸雨的成固,研究酸雨控制对策提供了科学依据。 相似文献
107.
Numerous analyses of the possible impacts of future climatic changes on tree species composition have been published for
both lowland and high-elevation forests. Most of these studies were based on the application of forest "gap" models, and the
vast majority of them considered only changes in the average of climatic parameters over time. In this study, we use a unique
data set on reconstructed past climatic variations to analyse forest dynamics simulated by the forest gap model ForClim. This
analysis forms the basis for a systematic exploration of the ecological effects of changing means vs. changing variability
of climate on central European forests. A reconstruction of historical climate covering the last 470 years in the Swiss lowlands
(ClimIndex) is extrapolated to a transect across the alpine (cold) treeline and used to simulate the influence of climate
variations on the time scale of decades on forest biomass and tree species composition at both sites. While the simulation
at the low-elevation site shows little sensitivity to climate variations, the results from upper subalpine forests suggest
that two major dieback events would have occurred at elevations above the current but below the climatic tree line, induced
by clusters of exceptionally cold summers. The results are in agreement with available dendrochronological data and with documentary
evidence on massive negative impacts on flora and fauna at high elevations during these periods. We conclude that ForClim
is capable of capturing the effects on tree population dynamics of climate variability at these sites as reconstructed from
the ClimIndex record. A factorial design is used to address the sensitivity of ForClim to changes of the long-term averages
vs. changes of the variability of monthly temperature and precipitation data. To this end, the simulated tree species composition
of near-natural forests is examined along a climate gradient in Europe. The results indicate that there are three types of
forest response: (1) little sensitivity to both kinds of change, (2) strong sensitivity to changes in the means, but little
sensitivity to changing variability, and (3) strong sensitivity to changing variability at least in parts of the examined
climate space. Half of the cases investigated fall under the third category, suggesting that emphasis should be placed on
also assessing the sensitivity of ecosystems to future changes in climate variability rather than on changes of average values
alone.
Electronic Publication 相似文献
108.
我国的海洋污染日益严重,政府加大海洋环境保护力度势在必行。科学、有效的海洋环境管理对保护环境、提高资源利用效率起着非常重要的作用。但海洋环境并不是一维线性的系统,涉及系统的多维耦合,而海岸带又是与人类活动息息相关的重要部分。本文尝试以青岛市胶州湾海岸带环境管理模式为例,构建包含有"经济-人口-资源-环境-安全-行政(EPRESA)"六个子系统的多维耦合系统模型,并绘制出总流图,然后以此为管理模式的优化提供前提性分析,提出海岸带综合管理模式优化的对策建议。本研究认为,要改善现有的海岸带环境管理体系,应该制定综合性管理政策,建立可持续的融资机制,推进海岸带灾害与风险管理以及引导利益相关者参与管理。 相似文献
109.
J. L. Hanisch B. R. Hart W. S. Turetsky H. T. Garabedian G. H. Pain 《Environmental management》1978,2(2):127-133
The body of information presented in this paper is directed to air pollution engineers who are concerned with the effect of indirect sources on ambient concentrations of carbon monoxide (CO). Data taken under controlled conditions are used to empirically derive and calibrate a model for predicting CO concentrations in the vicinity of roadway intersections and other points of possible vehicular congestion. Since the predicted free flow CO contribution of vehicles traveling at normal road speeds is relatively low, it is concluded that idling vehicles at points of congestion are the major cause of CO violations, and that state and federal programs should place more emphasis on relieving congestion and reducing idling emission rates in new vehicles. 相似文献
110.