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   369篇
  免费   69篇
  国内免费   48篇
安全科学   107篇
废物处理   35篇
环保管理   28篇
综合类   236篇
基础理论   6篇
污染及防治   52篇
评价与监测   10篇
社会与环境   1篇
灾害及防治   11篇
  2024年   1篇
  2023年   12篇
  2022年   11篇
  2021年   13篇
  2020年   14篇
  2019年   12篇
  2018年   10篇
  2017年   14篇
  2016年   16篇
  2015年   18篇
  2014年   19篇
  2013年   33篇
  2012年   36篇
  2011年   24篇
  2010年   27篇
  2009年   16篇
  2008年   7篇
  2007年   16篇
  2006年   19篇
  2005年   31篇
  2004年   20篇
  2003年   30篇
  2002年   12篇
  2001年   20篇
  2000年   11篇
  1999年   13篇
  1998年   9篇
  1997年   9篇
  1996年   2篇
  1995年   4篇
  1994年   2篇
  1993年   2篇
  1990年   1篇
  1989年   1篇
  1987年   1篇
排序方式: 共有486条查询结果,搜索用时 31 毫秒
101.
考虑实际修建过程中塔基岩石开挖的施工特点和砼分期浇筑特点,通过建立三维实体模型,根据基于大变形理论的快速拉格朗日方法,运用考虑库仑屈服准则的塑性接触面单元计算了锦屏一级水电站泄洪洞进口塔基砼-岩接触系统的应力和变形,评价了塔基的稳定性,并与直接考虑材料为实体单元的计算结果进行了比较。工程算例数值计算结果表明,采用接触面单元来分析砼-岩系统的力学行为更合理、更实用。  相似文献   
102.
It is important to study the characteristics of the nozzle of the deluge spray to comply with the standards developed by the petroleum industry for offshore installations in Norway. Due to the stochastic nature of the decomposition processes and geometrical features within the nozzle, the deluge spray has a complex flow field. Since the flow field determines the performance of the spray, the present study performs an experimental characterization of a medium velocity deluge nozzle for validation of computational fluid dynamics (CFD) models. The experiment was conducted for a maximum supply water pressure of 8.0 bar (g), which is identical to the operating pressures of offshore installations. Formerly, characterization studies of deluge or sprinkler spray were mostly targeted on residential usage with lower supply water pressures. I utilized a laser-based shadow imaging system to capture high-speed images, which were later processed in MATLAB. A linear patternator was used to validate the results of the shadow imaging technique. The geometrical features of the deluge nozzle played an important role in determining the characteristics of the spray. In addition, the supply water pressure significantly affected the size and velocity distributions of the droplets, applied density (volume flux), and area coverage. However, the Sauter mean diameter did not vary significantly with the azimuthal or radial position of the droplet within the inner region of the spray. The measurements obtained in this study can be used to estimate the extinguishing efficiency of a deluge system for offshore installations with elevated supply water pressures. Deviations between measurements with shadow imaging and patternator technique are discussed and discrepancies are discussed.  相似文献   
103.
喷雾干燥法在垃圾焚烧尾气净化中的应用   总被引:1,自引:0,他引:1  
以枣庄市资源电厂为例,介绍了喷雾干燥法在垃圾焚烧尾气净化中的应用。  相似文献   
104.
It is often difficult to measure and predict the impacts of toxic chemicals, such as herbicides, on natural communities. This is especially true under conditions of spray drift when the amount received by the organisms downwind from the sprayer may be at sub-lethal doses. Laboratory experiments are either artificial, or have not been generally carried out over long enough time periods, to be realistic. Field experiments are often difficult because of the high variability inherent in natural populations. Here an intermediate microcosm approach was used, where standardized artificial communities (eight dicotyledons with and without a grass) were tested. The artifical communities included species typical of British woodland margins, hedgerows and field margins; communities with a high conservation interest, yet potentially under threat from spray drift. The microcosms were placed downwind of a sprayer and exposed to one of the following herbicides: glyphosate, mecoprop and MCPA. This approach ensures that the communities were standardized at the start and have been exposed to realistic doses of herbicide. The experiments reported here were carried out for at least three years with exposures to herbicides repeated each year. The effects of differential herbicide exposure downwind of the sprayer were measured on species yield, flowering performance, seed production, seed viability and invasion by new species. Responses were extremely variable, but all species showed some effects in some years. Some patterns emerged. For example, one group of species appeared to be more successful near to the sprayer. This was particularly true of the grass when exposed to MCPA and mecoprop. The performance of most species was reduced under the sprayer, and there was a general recovery with increasing distance downwind. A few species showed increased performance in the intermediate downwind zone (2–4 m) and this may be due to a hormonal effect on growth processes, or an effect of reduced interference from other community members. Generally, there were few effects on seed production or seed viability. An important result was that most effects were confined within an 8 m zone, as there were few significant differences between plants exposed at 8 m and those untreated. Although damaging effects were found in the immediate downwind zone from the sprayer, the restriction of effects to 8 m suggests that a buffer zone of this size would be adequate to protect sensitive habitats from most deleterious impacts on community processes.  相似文献   
105.
YJT塔及其在三苯废气治理中的应用   总被引:1,自引:0,他引:1  
介绍了一种自行研制的YJT塔组合净化装置及其工艺,并简要阐述了有关注体力学参数,通过某制鞋厂的三苯废气治理表明,用零号柴油作吸收剂,其净化效率较高,经治理排放的废气浓度和排放速率均符合行业标准中的一级标准。  相似文献   
106.
玻璃建材厂含氟废气处理工程实践   总被引:1,自引:1,他引:1  
采用旋流板塔处理含氟废气,氟化物平均浓度从1085mg/Nm3降至75mg/Nm3,二氧化硫从7955mg/Nm3降至1263mg/Nm3,平均去除率氟化物为93%,二氧化硫841%  相似文献   
107.
梅荣武  陈芸 《环境工程》2000,18(1):32-33
论述了磷化铝生产废气的治理工艺、吸收剂选择及填料塔主要设计参数。水、液碱均可以作为吸收剂。以水为吸收剂,塔底出液pH<1时可用石灰乳中和后循环使用;当液碱作为吸收剂时P2O5被NaOH溶液吸收,当循环液中磷酸盐浓度较高时,可用来制作混合肥。  相似文献   
108.
水泥生产过程中燃煤产生的二氧化硫是当今主要的大气污染物 ,对水泥厂排放的废气进行治理是环境保护的重要课题之一。本文介绍了对水泥厂烟气进行低温脱硫的研究成果 ,阐述了喷雾干燥技术用于水泥厂废气脱硫的原理、设计方法  相似文献   
109.
陈锦灿 《环境工程》1995,13(2):41-44
本文综述了冷却塔噪声治理的主要进展。通过对冷却塔噪声的分析,提出了冷却塔噪声治理的途径。  相似文献   
110.
叙述了磺化法生产苯酚碱熔工段碱雾污染治理的技术措施 ,指出在原碱雾回收流程中的旋风分离器上部设置喷淋吸收装置 ,并采用 5 %~ 10 %的氢氧化钠碱液吸收碱雾 ,可取得明显的治理效果  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