全文获取类型
收费全文 | 923篇 |
免费 | 204篇 |
国内免费 | 69篇 |
专业分类
电工技术 | 40篇 |
综合类 | 58篇 |
化学工业 | 441篇 |
金属工艺 | 18篇 |
机械仪表 | 40篇 |
建筑科学 | 25篇 |
矿业工程 | 21篇 |
能源动力 | 57篇 |
轻工业 | 8篇 |
水利工程 | 140篇 |
石油天然气 | 64篇 |
武器工业 | 28篇 |
无线电 | 6篇 |
一般工业技术 | 123篇 |
冶金工业 | 15篇 |
原子能技术 | 18篇 |
自动化技术 | 94篇 |
出版年
2024年 | 1篇 |
2023年 | 17篇 |
2022年 | 24篇 |
2021年 | 26篇 |
2020年 | 37篇 |
2019年 | 41篇 |
2018年 | 35篇 |
2017年 | 47篇 |
2016年 | 55篇 |
2015年 | 59篇 |
2014年 | 58篇 |
2013年 | 69篇 |
2012年 | 66篇 |
2011年 | 66篇 |
2010年 | 47篇 |
2009年 | 50篇 |
2008年 | 39篇 |
2007年 | 50篇 |
2006年 | 46篇 |
2005年 | 46篇 |
2004年 | 40篇 |
2003年 | 33篇 |
2002年 | 33篇 |
2001年 | 31篇 |
2000年 | 23篇 |
1999年 | 26篇 |
1998年 | 13篇 |
1997年 | 23篇 |
1996年 | 18篇 |
1995年 | 13篇 |
1994年 | 11篇 |
1993年 | 6篇 |
1992年 | 11篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1974年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有1196条查询结果,搜索用时 15 毫秒
201.
喷射式并流填料塔板流体力学和传质性能 总被引:9,自引:1,他引:8
提出一种新型高效塔板——喷射式并流填料塔板(JCPT),介绍1200mm冷模塔流体力学实验结果和200mm热模塔传质效率,给出了适用于工业设计性能参数的计算关联式。通过与新垂直筛板(NVST)的比较表明,JCPT具有雾沫夹带小、处理能力大、塔板效率高等特点,是一种具有广泛应用前景的新型高效塔板。 相似文献
202.
203.
204.
Wei Liu Faïçal Larachi Guang-Wen Chu Yong Luo Seyed Mohammad Taghavi 《American Institute of Chemical Engineers》2023,69(1):e17424
Two-dimensional visualizations of point-source liquid spills in porous media were performed in a flat rectangular packed bed, emplaced on a robotized hexapod, to emulate roll/pitch marine oscillations. The extent to which the directional modulation of liquid gravity and the moving-bed inertial forces affect the liquid spills was the study's central aim. Spill morphology deviations were dictated by gravity force oscillations, while Coriolis/Euler/centrifugal forces were confined to secondary roles. Multiple gravity-driven liquid branching with departures from the longitudinal direction, not only boosted wetting but also symmetrized the developing spills while suppressing the wall-biased liquid influx, which impaired inclined beds. Wetting exhibited asymmetric sigmoidal deceleratory transients, reminiscent of many physicochemical transformations with skewed activation energy distribution. The parameters describing the dispersive kinetics and allied activation energy distribution of wetting—analogized to a phase change transition—were interpreted in terms of hexapod kinematic parameters. 相似文献
205.
运用高速摄像技术对流量脉动条件下旋流分离器内气泡动力学行为及气液两相流流型展开研究。研究发现,在完整脉动周期内,流量在3.62~4.18 m3/h范围内波动,流量增大段的气核整体向溢流口方向运移,流量减小段的气核整体向底流口方向运移,气核大小及形态变化呈现周期往复性。通过脉动周期内特殊帧的分析,得出流量脉动条件下旋流场内气液两相流流型主要包括:气泡流、塞状流、弹状流、丝状流及波状流等五种形式。根据实验得出的气液两相折算速度,确定了脉动条件下气液两相流流型转换界限图,而气泡间的聚并破碎行为是产生气液两相流型的主要原因,最终构建了表征截面含气量和分离效率之间关系的评价模型。 相似文献
206.
207.
优化内螺纹管在低质量流速直流锅炉设计中的应用 总被引:2,自引:0,他引:2
为解决传统UP炉存在的水冷壁热敏感性强、调峰能力受限制、锅炉运行安全性差等问题,姚孟发电有限责任公司1号锅炉水冷壁改造采用低质量流速设计,使用优化内螺纹管作传热元件,使运行中的水冷壁具有很适的正流量响应能力。这种特性使垂直管水冷壁具有很好的抗热偏差能力,全负荷范围内水动力稳定,并满足机组滑压运行要求。这种低质量流速设计开创了直流锅炉水动力设计的新理念,也为国产UP炉改造提供了新思路。 相似文献
208.
《Advanced Powder Technology》2019,30(12):2997-3009
During screening, a liquid stream, besides the vibration, can be applied for the acceleration of the separation. The discrete element method coupled with the smoothed particle hydrodynamics (DEM-SPH) is used to numerically analyse wet continuous screening here. Within the applied DEM-SPH a new simple model for the representation of the screening surface is suggested in this study. In this model, the influence of the screening surface on the fluid is represented using external forces, which act on the SPH particles in close vicinity of the screen. A required validation of the DEM-SPH method for the analysis of a vibrated particle-laden system is performed by comparing obtained DEM-SPH results with the results derived using the DEM coupled with finite volume method. The performed simulations of dry and wet continuous screening demonstrate that flowing water, in most simulated cases, accelerates the separation of particles. The presented study demonstrates the potential of the coupled DEM-SPH method for the analysis of wet screening processes. To our best knowledge, the simulation of wet screening using a two-way coupled numerical DEM-SPH approach not resolving the flow around individual particles is demonstrated in the scientific literature for the first time. 相似文献
209.
Saier Liu Guangxiao Li Minjing Shang Zheng-Hong Luo Yuanhai Su 《American Institute of Chemical Engineers》2021,67(11):e17362
Hydrodynamics characteristics of a fast and highly exothermic liquid–liquid oxidation process with in situ gas production in microreactors were studied using a newly developed experimental method. In the adipic acid synthesis through the K/A oil (the mixture of cyclohexanol and cyclohexanone) oxidation with nitric acid, bubble generation modes were divided into four categories. The gas production became more intensive, unstable, even explosive with increasing the oil phase feed rate and the temperature. A novel automatic image processing method was developed to monitor the instantaneous velocity online by tracking the gas–liquid interface. The axial velocity at the same location was unstable due to the changing gas production rate. Furthermore, the actual residence time was obtained easily with being only 36% of the space–time minimally, beneficial for establishing accurate kinetics and mass transfer models with time participation. Finally, an empirical correlation was developed to predict the actual residence time under different conditions. 相似文献
210.
AbstractWithin the framework of Timoshenko beam theory, the buckling of nano sandwich beams is developed. The material properties are assumed to vary arbitrarily in both axial and thickness directions. These types of beams are referred to as bi-directional functionally graded (BDFG) beams. Two types of nano sandwich beams with different material distribution patterns and immovable supports are considered. Since the size effects play a significant role in mechanical behavior of nanostructures, the small-scale effects are captured by Eringen’s nonlocal theory of elasticity. The governing equations are derived using the variational formulation. Symmetric smoothed particle hydrodynamics (SSPH) and the Galerkin method are adopted as numerical solution approaches. As a truly meshless method, the convergence of the SSPH technique mainly depends on the smoothing length value and distribution of particles in the compact support domain of the kernel function. The Revised Super Gauss Function is used as the kernel function and an optimum value for the smoothing length that bears the fastest convergence rate is obtained. The solution methods are verified through benchmark problems found in the literature. Numerical and illustrative results show that various parameters, including the aspect ratio, nonlocal parameter, gradient indexes, and cross-sectional types have significant effects on the buckling responses of BDFG nano sandwich beams. 相似文献