全文获取类型
收费全文 | 280篇 |
免费 | 6篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 133篇 |
废物处理 | 3篇 |
环保管理 | 12篇 |
综合类 | 55篇 |
基础理论 | 23篇 |
污染及防治 | 44篇 |
评价与监测 | 11篇 |
社会与环境 | 1篇 |
灾害及防治 | 9篇 |
出版年
2024年 | 1篇 |
2023年 | 12篇 |
2022年 | 4篇 |
2021年 | 13篇 |
2020年 | 3篇 |
2019年 | 8篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 5篇 |
2015年 | 19篇 |
2014年 | 10篇 |
2013年 | 17篇 |
2012年 | 13篇 |
2011年 | 10篇 |
2010年 | 5篇 |
2009年 | 13篇 |
2008年 | 9篇 |
2007年 | 10篇 |
2006年 | 12篇 |
2005年 | 6篇 |
2004年 | 16篇 |
2003年 | 12篇 |
2002年 | 3篇 |
2001年 | 14篇 |
2000年 | 14篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 6篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有291条查询结果,搜索用时 218 毫秒
71.
叶片断裂和裂纹是旋转机械中普遍存在的一种安全隐患。对其发生规律进行分析是十分重要的。笔者针对地铁通风系统的某型号 18#轴流式风机发生断裂和出现裂纹的情况 ,采用Star—CD流体计算软件和ANSYS有限元软件计算了有、无软连接两种情况下的风机内流场和风机叶片的内应力。结果表明 ,软连接结构虽然对风机的内流场和叶片内应力有影响 ,但不足以对风机安全运行构成威胁。同时 ,分析了导致叶片断裂和出现裂纹的多种因素 ,并提出了避免类似现象发生的若干建议。 相似文献
72.
73.
利用温度反演和数值模拟的方法,对田湾核电站航天遥感测量和数值模拟结果作对比分析。结果显示:遥感监测和数值模拟结果在田湾核电站附近海域的海面温度场羽迹展布方向、不同季节大小潮型、潮态规律上都是相似的,只是在规模和数量上存在着一定差异,两者可以相互验证。 相似文献
74.
75.
M. Konz A. Younes P. Ackerer M. Fahs P. Huggenberger E. Zechner 《Journal of contaminant hydrology》2009,108(3-4):168-175
Konz, M., Ackerer, P., Younes, A., Huggenberger, P., Zechner, E., 2009a. 2D Stable Layered Laboratory-scale Experiments for Testing Density-coupled Flow Models. Water Resources Research, 45. doi:10.1029/2008WR007118., a series of laboratory-scale 2D tank experiments were conducted and accurately simulated for density driven flow problems on homogeneous porous media. In the present work, we extended the numerical and experimental studies to heterogeneous problems. The heterogeneous porous medium was constructed with a low permeability zone in the centre of the tank and had well-defined parameters and boundary conditions. Concentration distributions were measured in high resolution using a photometric method and an image analysis technique. The numerical model used for the simulations was based on efficient advanced approximations for both spatial and temporal discretizations. The Method Of Lines (MOL) was used to allow higher-order temporal discretization. Three different boundary conditions, corresponding to different localizations of the inflow and the outflow openings at the opposite edges of the tank, were applied to investigate different flow scenarios in the heterogeneous porous medium flow tank. Simulation results of all three density coupled experiments revealed a density-dependent behavior of dispersion. Thus, a reduction of dispersivites was required to obtain a good matching of the experimental data. The high quality of the experiments enabled a detailed testing of numerical variable-density flow codes under heterogeneous conditions. Therefore, the experiments were considered to be reliable benchmark tests. 相似文献
76.
A method for quick assessment of CO2 storage capacity in closed and semi-closed saline formations 总被引:1,自引:0,他引:1
Quanlin Zhou Jens T. Birkholzer Chin-Fu Tsang Jonny Rutqvist 《International Journal of Greenhouse Gas Control》2008,2(4):626
Saline aquifers of high permeability bounded by overlying/underlying seals may be surrounded laterally by low-permeability zones, possibly caused by natural heterogeneity and/or faulting. Carbon dioxide (CO2) injection into and storage in such “closed” systems with impervious seals, or “semi-closed” systems with non-ideal (low permeability) seals, is different from that in “open” systems, from which the displaced brine can easily escape laterally. In closed or semi-closed systems, the pressure buildup caused by continuous industrial-scale CO2 injection may have a limiting effect on CO2 storage capacity, because geomechanical damage caused by overpressure needs to be avoided. In this research, a simple analytical method was developed for the quick assessment of the CO2 storage capacity in such closed and semi-closed systems. This quick-assessment method is based on the fact that native brine (of an equivalent volume) displaced by the cumulative injected CO2 occupies additional pore volume within the storage formation and the seals, provided by pore and brine compressibility in response to pressure buildup. With non-ideal seals, brine may also leak through the seals into overlying/underlying formations. The quick-assessment method calculates these brine displacement contributions in response to an estimated average pressure buildup in the storage reservoir. The CO2 storage capacity and the transient domain-averaged pressure buildup estimated through the quick-assessment method were compared with the “true” values obtained using detailed numerical simulations of CO2 and brine transport in a two-dimensional radial system. The good agreement indicates that the proposed method can produce reasonable approximations for storage–formation–seal systems of various geometric and hydrogeological properties. 相似文献
77.
河道污染质垂向迁移对地下水影响的研究 总被引:5,自引:1,他引:4
包气带是连接地表水和地下水的重要通道,对地下水资源有很好的"屏障"功能,而近年来工农业废水及生活污水的大量排放已影响到了地下水的"安全".为此,在渭河河漫滩进行了模拟河流的垂向入渗试验,并通过建立数学模型对水分和六价铬在具有弱透水层的多层介质中的迁移进行了模拟运算.试验和模拟结果一致表明,弱透水层虽对地下水有很好的保护作用,但在上部土壤层易形成面状污染带,而且由于大的浓度梯度作用,一旦污染质穿透该层将很快污染到地下水. 相似文献
78.
Ji-Quan Shi Ziqiu Xue Sevket Durucan 《International Journal of Greenhouse Gas Control》2007,1(4):473-480
This paper reports on an integrated laboratory and numerical simulation study of ultrasonic P-wave velocity response to supercritical CO2 displacement of pore water in Tako sandstone. The analysis of dynamic velocity data recorded using an array of piezoelectric transducers mounted on a core sample showed that the P-wave velocities at different positions displayed a similar trend in time, i.e., an initial sharp fall followed by a more gradual decline. Considerable variations observed in the measured P-wave velocity reductions across the sandstone core could largely be attributed to the final state of saturation (e.g. uniform, patchy or in-between) attained by the two-phase fluids. Numerical simulation of the injection test using a simple 1D model was carried out to provide an estimation of the phase saturation changes underlying the measured P-wave velocity reductions. A second order polynomial correlation between the measured ultrasonic P-wave velocity reductions and the estimated CO2 saturation was established. Comparison with the Gassmann velocities showed that the empirically established relationship marks a clear deviation from both the patchy and uniform saturation velocity curves. 相似文献
79.
Electromagnetic fields exposure assessment methodology is briefly presented. The basic problems defined for the practical
use of electromagnetic fields measurements and numerical calculations carried out for workers exposure assessment in real
occupational situations are discussed. The examples of data from real workplace are presented, focusing: spatial distribution
of electromagnetic fields affecting worker’s body, complex characteristics of the frequency content, workers activities/moving
in the workplace, field impedance, etc. The situation when the use of calculations is required is discussed. The basic requirements
for workers exposure assessment protocols are presented. The possible range of the use of internal and external measures of
exposure level is also discussed. 相似文献
80.
甲烷-煤尘爆炸波与障碍物相互作用的数值研究 总被引:8,自引:2,他引:6
为了探讨煤矿瓦斯和煤尘爆炸的物理机制 ,基于对甲烷和煤尘爆炸传播的理论分析 ,采用数值模拟方法研究障碍物对甲烷和煤尘爆炸传播的影响 ;为了更系统地考虑颗粒相各种输运特性、相间滑移和耦合 ,采用双流体模型建立了数学模型 ,该模型的出发点是把颗粒群和气体都作为连续介质 ,两者相互渗透充满整个空间形成没有间隙的“流体”———拟流体 ,在欧拉坐标系下考虑气 -固两相流动 ,气相和颗粒相的计算网格统一 ,易于处理。数值方法采用LU分解和迎风TVD格式分别处理对流项的隐式和显式部分 ,扩散项采用中心差分 ;同时研究了不同形状的障碍物对流场的影响 ,计算结果与实验吻合较好 相似文献