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721.
722.
阐述了六安市城市生活垃圾产量预测的两种方法——根据人均垃圾日产量指标预测和根据垃圾年增长率预测。为缺乏相关基础资料的小城市探索了一些新的垃圾产量的预测方法。 相似文献
723.
Brownfields are abandoned, idled, or underused sites whose reuse necessitates some sort of intervention. These sites are largely
urban and are frequently contaminated. Brownfield management options can be associated with three types of environmental consequences:
those resulting from changes in the site’s environmental quality (primary impacts); those resulting from the actual intervention
stage (secondary impacts); and, if the vocation of the site changes, those resulting from effects on regional land use (tertiary
impacts). Different stakeholders and decision-making contexts will place a different importance on each of these types of
impacts. This article proposes a framework for comparing brownfield management options in regard to these three types of environmental
impacts and for interpreting these results from different perspectives. The assessment framework is based on consequential
life cycle assessment (LCA), which is shown to provide environmental information on the three types of impacts. The results
for a case study are presented, where a “rehabilitation” option allowing residential redevelopment is compared to an “exposure
minimization” option not resulting in the site being reused. Calculated primary and tertiary impacts are favorable to the
rehabilitation option, whereas secondary impacts are favorable to the exposure minimization option. A ternary diagram presents
the favorable option for different stereotypical perspectives. Tertiary impacts are much greater than secondary impacts, and
consequently all perspectives that consider tertiary impacts favor rehabilitation. The perspective that considers primary
and secondary impacts receives conflicting information. The ternary diagram, showing results for all perspectives, could possibly
be useful for consensus-building among stakeholders. 相似文献
724.
某工业场地砷污染的加密布点优化与精度对比分析 总被引:1,自引:0,他引:1
场地污染调查是开展场地风险评估和修复的基础,随着我国颁布建设用地土壤风险管控标准等文件,提出风险筛选值和管制值的分级管控体系,我国土壤污染调查工作对于精确掌握污染物浓度梯度及空间分布有了更高的要求,因而如何构建高效采样布点方法变得尤为重要.本研究以南京市某砷工业污染场地为例,开展了优化布点方法与调查精度的研究.首先,在初查数据的基础上,运用指示克里格的方法预测土壤污染概率,参考城市土壤背景值开展阈值设定,提取加密布点区域,之后结合场地历史生产资料与自然信息布设加密点位,最终将插值预测污染结果与非加密、均匀加密、真实情况结果进行对比,验证方法精度.结果表明:本方法符合国际中基于设计抽样以达到场地调查简单、经济、客观的理念,适用于数据存在明显空间相关性的场地;该方法获得的污染区域面积占比为8.32%,与8.57%的现实情况较为接近,但普通法得到的污染面积比相对未加密情况不升反降,可能的原因是在非污染区域增设点位会造成阈值边缘区域在模拟时往清洁区域偏移,污染区域被误判为清洁,反而造成结果偏差;在目前我国环境管理对超阈范围重点关注的背景下,该方法既能够节约布点成本,又精确化预测场地污染超标范围,为后续的场地修复和治理工作提供帮助. 相似文献
725.
于家沟遗址作为泥河湾盆地中唯一具有新旧石器工业过渡的典型遗址,为研究东亚旧石器向新石器时代过渡提供了理想的场所。本文通过于家沟遗址剖面沉积物(厚约550 cm)的加速器质谱法(AMS-~(14)C)年代测定,确定了于家沟剖面的年代跨度为16.19?—?2.43 ka BP,其中旧石器向新石器时代的转化时限为9.35 ka BP。该遗址中发现的最早陶器经同层位地层推测,其年代为13.60 ka BP,是目前中国北方发现的最早陶器。陶器的使用可能改善了古人类的生活条件;大量细石器反映出泥河湾盆地中采猎经济高度繁荣。因此,在晚更新世末期气候开始变暖的背景下陶器和细石器的出现一定程度推动了中国北方旧石器时代向新石器时代的转变。 相似文献
726.
Stephen C. Newbold 《Environmental Modeling and Assessment》2005,10(3):251-263
Most landscape design models have been applied to the problem of maximizing species richness in a network of nature reserves.
This paper describes a combined hydrologic simulation and landscape design model designed to prioritize sites for wetlands
restoration, where the objective is to maximize the amount of nutrients in non-point-source runoff attenuated in the restored
wetlands. Targeted site selection in four small watersheds in the Central Valley resulted in predicted levels of nitrogen
attenuation two to eight times greater than that from maximizing wetland area without consideration of the location of the
restoration sites.
Disclaimer The views expressed in this paper are those of the author and do not necessarily represent those of the US Environmental Protection
Agency. No official Agency endorsement should be inferred. 相似文献
727.
Kalliat T. Valsaraj Raghava R. Kommalapati Edward D. Robertson W. D. Constant 《Environmental monitoring and assessment》1999,58(2):227-243
The adsorption of four volatile organic compounds (1,4-dichloro-benzene, 1,2-dichloroethane, 1,2,2-trichloroethane and 1,1,2,2,-tetrachloroethane) on three soil types from a Superfund site (Petroprocessors Inc) in Baton Rouge, LA was studied with the purpose of obtaining an overall correlation for inclusion in a groundwater transport model being developed for site remediation. The soil-water partition constant, Kd was determined using a standard ASTM procedure (E–1195–87). Using the data for different soil types (fraction organic carbon between 0.11% and 1.13%) and different mineral surface areas (7 to 45 m2/g), the organic carbon contribution (Koc) and the mineral matter contribution (Kmin) to the partition constant were determined. The soils obtained were either from the Pleistocene period or recent shallow deposits at the site. Both log Koc and log Kmin were linearly correlated to log Kow, the octanol-water partition constant. This data provided the basis for obtaining a general correlation for Kd on different soil types at the site. The predicted values were in agreement with that for a composite soil from the same site. The desorption of compounds from the high clay soil after the 24 hour adsorption period was observed to show a biphasic behavior, namely, an easily desorbed fraction and a desorption resistant fraction. The easily desorbed fraction was found to be satisfactorily predicted using the conventional Kd as obtained from the adsorption experiment. The slowly desorbing fraction had a time constant of several weeks. The concentration in the desorption resistant compartment was found to be dependant on the initial amount of contaminant available for adsorption. The aqueous phase concentration in equilibrium with the desorption resistant fraction was found to be 8 g/L for dichlorobenzene and 12 g/L for dichloroethane. 相似文献
728.
729.
730.
不同垃圾填埋单元土壤--植物系统中汞的污染和迁移 总被引:4,自引:0,他引:4
对上海老港垃圾填埋场不同年份填埋单元的表层履土,以及典型植物中汞的分布进行了分析研究。结果发现,自1989-2001年共13a间不同时间的垃圾填埋单元表层土壤中,汞浓度与填埋时间有一定关系:从1989年到1993年,土壤汞浓度呈逐年递减趋势;从1998年到2001年又呈递增趋势;而中间几年出现汞浓度异常现象。土壤总汞、结合态汞和可挥发汞的浓度与土壤有机质含量有显著的相关性,相关系数分别为0.8147、0.8045和0.8213。另外,被调查植物体内汞的分布特点为:叶汞>根汞>茎汞。填埋时间较长的几个单元中,典型植物(加拿大黄花)的根汞与土壤可挥发汞有较好的相关性。 相似文献