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   106篇
  免费   1篇
  国内免费   13篇
安全科学   24篇
废物处理   3篇
环保管理   17篇
综合类   34篇
基础理论   12篇
污染及防治   14篇
评价与监测   11篇
灾害及防治   5篇
  2023年   1篇
  2022年   1篇
  2021年   2篇
  2020年   3篇
  2019年   5篇
  2018年   3篇
  2016年   3篇
  2015年   1篇
  2014年   5篇
  2013年   6篇
  2012年   5篇
  2011年   7篇
  2010年   3篇
  2009年   6篇
  2008年   6篇
  2007年   1篇
  2006年   9篇
  2005年   8篇
  2004年   6篇
  2003年   8篇
  2002年   3篇
  2001年   1篇
  2000年   6篇
  1999年   3篇
  1998年   5篇
  1997年   1篇
  1996年   2篇
  1995年   2篇
  1994年   2篇
  1992年   1篇
  1991年   2篇
  1990年   1篇
  1987年   1篇
  1983年   1篇
排序方式: 共有120条查询结果,搜索用时 78 毫秒
71.
A case study of Dahu landslide from Linbao Henan in China was discussed in this paper. Based on various kinds of basic data, the 3D numerical model of a geological structure which possesses all kinds of information including the mechanical characteristics and the geometrical parameters of geological discontinuities were known from previous works. Thus, both the whole geological structure and all kinds of geological components involved in a slope can be visualized on computer, the complicated analysis and calculation can be then carried out easily and effectively. Firstly, the combination of 3D numerical model with the limit equilibrium analysis theory in slope stabilization can easily provide the present stability factor. Then according to monitoring data of the total station, the potential sliding trends are analyzed if landslides do not occur. Secondly, there are a number of uncertainties on the factors of multi-forms of disaster, such as, rainfall, earthquake, and mined-out area. The unascertained mathematics theory is applied to the stability comprehensive evaluation. It shows four landslide bodies get to be at unstable state if there are some inducements. Thirdly, sliding distance and movement scope were predicted if landslides occur. On the basis of the analysis above, the treatment of the landslide body called isolated method of culvert was proposed. It has solved the contradiction of landslide and mining radically, and provides important technical assurance for safety and sustainable development of mine.  相似文献   
72.
对沈阳市地表水环境特征及水质达标现状进行了分析,论述了地表水变化趋势,提出了实现地表水持续稳定达标的技术路径,要实现地表水环境质量持续稳定达标,必须采取优化经济结构及布局,持续推进污水集中控制,强化污染源治理,实施农村环境综合整治,提升河流生态环境质量和水体自净能力,强化水环境政策制度建设及环境监管等有效措施。  相似文献   
73.
Fe/Al drinking water treatment residuals (WTRs), ubiquitous and non-hazardous by-products of drinking water purification, are cost-effective adsorbents for glyphosate. Given that repeated glyphosate applications could significantly decrease glyphosate retention by soils and that the adsorbed glyphosate is potentially mobile, high sorption capacity and stability of glyphosate in agricultural soils are needed to prevent pollution of water by glyphosate. Therefore, we investigated the feasibility of reusing Fe/Al WTR as a soil amendment to enhance the retention capacity of glyphosate in two agricultural soils. The results of batch experiments showed that the Fe/Al WTR amendment significantly enhanced the glyphosate sorption capacity of both soils (p < 0.001). Up to 30% of the previously adsorbed glyphosate desorbed from the non-amended soils, and the Fe/Al WTR amendment effectively decreased the proportion of glyphosate desorbed. Fractionation analyses further demonstrated that glyphosate adsorbed to non-amended soils was primarily retained in the readily labile fraction (NaHCO3-glyphosate). The WTR amendment significantly increased the relative proportion of the moderately labile fraction (HCl-glyphosate) and concomitantly reduced that of the NaHCO3-glyphosate, hence reducing the potential for the release of soil-adsorbed glyphosate into the aqueous phase. Furthermore, Fe/Al WTR amendment minimized the inhibitory effect of increasing solution pH on glyphosate sorption by soils and mitigated the effects of increasing solution ionic strength. The present results indicate that Fe/Al WTR is suitable for use as a soil amendment to prevent glyphosate pollution of aquatic ecosystems by enhancing the glyphosate retention capacity in soils.  相似文献   
74.
弹塑性极限平衡法分析复杂岩质边坡的稳定性   总被引:4,自引:1,他引:4  
笔者采用弹塑性极限平衡法来研究分析复杂岩质边坡的稳定性 ,即以塑性极限理论为基础 ,应用逐渐降低材料强度来逼近系统的极限平衡 ,并以屈服区的贯通来表征系统的极限平衡状态。此时 ,系统达到临界平衡状态时所对应的材料强度降低倍数即为整体最小安全系数 ,临界平衡状态定义为边坡内的塑性屈服区能够形成潜在的滑移通道时的状态。以城门山露天矿南帮边坡为研究对象 ,通过自行改编的NCAP -FS程序进行了数值分析 ,结果表明 ,南帮边坡现阶段是安全稳定的 ,与现场观测结果一致。  相似文献   
75.
评估固体废弃物堆肥腐熟和稳定的研究   总被引:17,自引:1,他引:17  
用化学方法、生物活性及植物毒性分析等技术,从腐熟和稳定两个方面对堆肥成熟的评估方法作了综述,推荐了几种常用,有用的评估堆肥腐熟和稳定的方法,包括微生物、CO2的产和玫O2的吸收、植物发芽实验、水溶性有机C/N比和腐殖质等化合物的组分的变化,随着分析技术和微生物技术发展,先进、快捷的堆肥评估方法,不断出现,堆肥的生产和使用者可根据实际情况,选择合适的评估方法  相似文献   
76.
Photocatalytic degradation was considered as a best strategy for the removal of antibiotic drug pollutants from wastewater. The photocatalyst of ABC (Ag2CO3/BiOBr/CdS) composite synthesized by hydrothermal and precipitation method. The ABC composite used to investigate the degradation activity of tetracycline (TC) under visible light irradiation. The physicochemical characterization methods (e.g. scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution-transmission electron microscopy (HR-TEM), ultraviolet visible spectroscopy (UV), photoluminescence (PL) and time resolved photoluminescence (TRPL) clearly indicate that the composite has been construct successfully that enhances the widened visible light absorption, induces charge transfer and separation efficiency of electron – hole pairs. The photocatalytic activity of all samples was examined through photodegradation of tetracycline in aqueous medium. The photocatalytic degradation rate of ABC catalyst could eliminate 98.79% of TC in 70 min, which is about 1.5 times that of Ag2CO3, 1.28 times that of BiOBr and 1.1 times that of BC catalyst, respectively. The role of operation parameters like, TC concentration, catalyst dosage and initial pH on TC degradation activity were studied. Quenching experiment was demonstrated that ·OH and O2· were played a key role during the photocatalysis process that was evidently proved in electron paramagnetic resonance (EPR) experiment. In addition, the catalyst showed good activity perceived in reusability and stability test due to the synergistic effect between its components. The mechanism of degradation of TC in ABC composite was proposed based on the detailed analysis. The current study will give an efficient and recyclable photocatalyst for antibiotic aqueous pollutant removal.  相似文献   
77.
The natural histories of crop-related wild species in their native habitats can be used to develop novel pest management strategies. Traditionally, such information has provided insights for biological control, plant breeding, crop management, and applied ecology Further insights can be garnered.  相似文献   
78.
The concept of succession has a distinguished history in general ecology and has been applied to stream ecosystems with some success. Succession in streams is largely secondary, follows initial floristics models, and occurs through a variety of mechanisms. The process is moderately predictable but is highly influenced by “climatic” factors, particularly nutrient chemistry. In desert streams, succession does not result in a climax state. While evidence is slim, succession may not be a significant process in streams of certain types or in certain regions. Successional theory is difficult to apply in spatially heterogeneous, hierarchically organized ecosystems. It also suffers in being only one component of a better integrated concept, that of ecosystem stability, which deals more directly with disturbance and ecosystem resistance in addition to resilience (which encompasses succession). Succession has so suffered from a half century of confusion that a strong case can be made for abandoning the term, at least as it applies in streams, in favor of the broader view provided by stability theory.  相似文献   
79.
超高压水射流系统压力的稳定是系统提高切割性能的关键,稳压器容积的大小、方向阀转换时间、喷嘴直径是影响系统压力稳定的主要因素。分析了系统压力稳定过程,并对三种不同容积的稳压器分别进行了试验研究,所得结论对系统压力稳定性的提高具有指导意义。  相似文献   
80.
测定了长时间保存的1.0000g/L苯酚贮备液的浓度和标样。结果表明此浓度的苯酚贮备液可在3年内保持稳定。  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