全文获取类型
收费全文 | 4304篇 |
免费 | 402篇 |
国内免费 | 415篇 |
专业分类
安全科学 | 1129篇 |
废物处理 | 61篇 |
环保管理 | 649篇 |
综合类 | 1898篇 |
基础理论 | 406篇 |
环境理论 | 11篇 |
污染及防治 | 119篇 |
评价与监测 | 264篇 |
社会与环境 | 330篇 |
灾害及防治 | 254篇 |
出版年
2024年 | 18篇 |
2023年 | 64篇 |
2022年 | 99篇 |
2021年 | 153篇 |
2020年 | 160篇 |
2019年 | 119篇 |
2018年 | 102篇 |
2017年 | 179篇 |
2016年 | 219篇 |
2015年 | 204篇 |
2014年 | 211篇 |
2013年 | 282篇 |
2012年 | 384篇 |
2011年 | 425篇 |
2010年 | 309篇 |
2009年 | 254篇 |
2008年 | 188篇 |
2007年 | 255篇 |
2006年 | 275篇 |
2005年 | 194篇 |
2004年 | 159篇 |
2003年 | 134篇 |
2002年 | 96篇 |
2001年 | 92篇 |
2000年 | 80篇 |
1999年 | 59篇 |
1998年 | 59篇 |
1997年 | 44篇 |
1996年 | 45篇 |
1995年 | 44篇 |
1994年 | 29篇 |
1993年 | 32篇 |
1992年 | 27篇 |
1991年 | 17篇 |
1990年 | 9篇 |
1989年 | 11篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 9篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1976年 | 3篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1972年 | 7篇 |
排序方式: 共有5121条查询结果,搜索用时 484 毫秒
391.
江苏沿海滩涂开发现状分析 总被引:6,自引:0,他引:6
本文作者根据多年的江苏滩涂开发利用调查资料,着重分析了江苏滩涂开发成就,开发潜力和制约因素三方面的现状,提出了加快滩涂开发的重要措施。 相似文献
392.
本文根据西岭雪山景区特色,将其分为三大景观区,从景观的美学价值出发,选择了12个美学评价指标,运用层次分析法和征询评分加权法,对该风景区进行了环境美学综合评价。 相似文献
393.
An Experiment in Participative Environmental Decision Making 总被引:2,自引:0,他引:2
Summary The paper presents a method of participatory decision-making involving the authorities at local level, experts and the public.
It studies how to solve the problems caused by the heterogeneity of the parties taking part in the decision-making process.
The method builds on mutual learning and consideration among the participants following a systematic approach led by a moderator.
The method was tested at a workshop simulating a real-life situation. The test case studied at the workshop was the problem
of identifying the best site for a low and intermediate level radioactive waste repository among three alternatives. The learning
phase was the Krško Nuclear Power Plant cooling problem. The results show that the participants were able to reach agreement
on the prioritisation of the alternatives and to end up with suprisingly complex and fully reasonable decision models. We
believe that this was achieved particularly due to the well defined procedure that guided the decision-making process, and
the ability of all participants to see the influence of their views on the decision model. 相似文献
394.
This paper presents result from an economic and technical point of view evaluation study, which has sought to establish the potential for replacing well-water that is currently used at the Piaggio industrial plant in Pontedera with recycled wastewater. The study is based upon a pilot wastewater treatment plant, which has been used to test wastewater treatment processes and to compare with achieved quality of recycled waters with that of water drawn on-site from physical/chemical pre-treatment and end with a reverse osmosis and air stripping stage. However, after the physical/chemical pre-treatment, the first option uses oxidation with ozone followed by activated carbon filtration, whereas the second method uses ultrafiltration. The first method is more effective at reducing chemical oxygen demand (COD) whereas the second method is more effective in removing bacteria. Nonetheless, both methods deliver water for re-use of a quality comparable with or better than that of well-water. In principle, the reverse osmosis permeate from either process could be re-used in all production phases at the industrial plant. However, the method base upon oxidation with ozone followed by activated carbon filtration is preferred, because, the process is simpler and continuous. The economic analysis of this process gives an estimated cost of Euro 0.55 per m3 for treated water. This compares favorably with other treatment processes and with the cost of other forms of water supply, which are projected to increase in any case. 相似文献
395.
基于小波包分析的爆破振动危害评价初探 总被引:2,自引:0,他引:2
结合振动主频的质点振速判据是对单一质点振速判据的补充和完善.但该判据的振动主频是通过FFT变换的频谱分析的方法获得的,不能体现爆破振动波形的多主振频带特征,而且由于方法本身的局限性使得主振频率发生的时间段不能确定.小波包分析法则克服了FFT频谱分析的局限,有效地分解和重构原始信号中的细节信号,并将其作为评价不同频率细节信号的爆破振动危害效果的基础.本文针对爆破振动的小波包分析法进行了研究,对各小波包细节信号加载条件下的不同危害效果进行了讨论,得到了相应的质点振速判据,并将该方法所得到的判据与FFT变换的频谱分析方法所得到的判据进行了对比.结果表明,基于小波包分析法的质点振速判据更加符合爆破振动危害的真实情况. 相似文献
396.
397.
基于洪水灾害快速评估的承灾体易损性信息管理系统 总被引:5,自引:0,他引:5
洪水灾害易损性信息管理系统是为了开展洪水灾害快速评估,对不同洪水灾害流域和同一洪水灾害流域中的不同地区、不同承灾体(财产分类)、不同致灾因子(水深和历时等)条件,以财产的损失率为核心的综合信息管理系统。本文介绍了洪水灾害易损性信息管理系统的开发与设计的基本原理,阐述了系统的总体结构框架和功能模块划分,并且在系统数据流程图的基础上,对损失率数据库等几个重要的模块进行了详细的分析与设计,给出了系统的部分运行结果。本系统在与GIS、遥感等空间技术结合后,能够高效地完成各种洪水灾害损失的快速评估与预测分析工作,同时,本系统亦可独立作为对区域洪水灾害易损性研究的数据基础和理论支撑。 相似文献
398.
Lizhu Wang John Lyons Paul Kanehl 《Journal of the American Water Resources Association》2002,38(3):663-680
ABSTRACT: We evaluated the effectiveness of watershed‐scale implementations of best‐management practices (BMPs) for improving habitat and fish attributes in two coldwater stream systems in Wisconsin. We sampled physical habitat, water temperature, and fish communities in multiple paired treatment and reference streams before and after upland (barnyard runoff controls, manure storage, contour plowing, reduced tillage) and riparian (stream bank fencing, sloping, limited rip‐rapping) BMP installation in the treatment subwatersheds. In Spring Creek, BMPs significantly improved overall stream habitat quality, bank stability, instream cover for fish, abundance of cool‐ and coldwater fishes, and abundance of all fishes. Improvements were most pronounced at sites with riparian BMPs. Water temperatures were consistently cold enough to support coldwater fishes such as trout (Salmonidae) and sculpins (Cottidae) even before BMP installation. We observed the first‐time occurrence of naturally reproduced brown trout (Salmo trutta) in Spring Creek, indicating that the stream condition had been improved to be able to partially sustain a trout population. In Eagle Creek and its tributary Joos Creek, limited riparian BMPs led to localized gains in overall habitat quality, bank stability, and water depth. However, because few upland BMPs were installed in the subwatershed there were no improvements in water temperature or the quality of the fish community. Temperatures remained marginal for coldwater fish throughout the study. Our results demonstrate that riparian BMPs can improve habitat conditions in Wisconsin streams, but cannot restore coldwater fish communities if there is insufficient upland BMP implementation. Our approach of studying multiple paired treatment and reference streams before and after BMP implementation proved effective in detecting the response of stream ecosystems to watershed management activities. 相似文献
399.
It is common to use the results of various solid-phase and aqueous-fraction toxicity tests as part of the decision-making
process for selecting disposal options for dredged sediments. The mere presence of toxicity, however, does not provide a logical
basis for selecting economical, environmentally protective disposal techniques. To achieve this, it is necessary to be able
to identify specific compounds responsible for sediment toxicity. Toxicity identification evaluation (TIE) procedures, originally
developed for complex effluents, represent a useful approach for identifying acutely toxic compounds in dredged materials.
Herein we present a conceptual overview for TIE use in part of the decision-making framework for selecting dredged material
disposal options; included are discussions concerning appropriate test fractions and species for TIE analyses, and specific
TIE manipulations useful for ascertaining whether toxicity is due to any of a number of common sediment contaminants including
ammonia, hydrogen sulfide, metals, or nonpolar organics. 相似文献
400.
Keith Loague 《Journal of the American Water Resources Association》1992,28(4):687-693
ABSTRACT: In this paper a new set of soil texture data is used to estimate the spatial distribution of saturated hydraulic conductivity values for a small rangeland catchment. The estimates of conductivity are used to re-excite and re-evaluate a quasi-physically based rainfall-runoff model. The performance of the model is significantly reduced with conductivity estimates gleaned from soil texture data rather than the infiltration data used in our previous efforts. 相似文献