全文获取类型
收费全文 | 16019篇 |
免费 | 3160篇 |
国内免费 | 601篇 |
专业分类
电工技术 | 6247篇 |
综合类 | 1437篇 |
化学工业 | 771篇 |
金属工艺 | 177篇 |
机械仪表 | 1062篇 |
建筑科学 | 2057篇 |
矿业工程 | 286篇 |
能源动力 | 3704篇 |
轻工业 | 79篇 |
水利工程 | 836篇 |
石油天然气 | 209篇 |
武器工业 | 190篇 |
无线电 | 526篇 |
一般工业技术 | 1110篇 |
冶金工业 | 191篇 |
原子能技术 | 90篇 |
自动化技术 | 808篇 |
出版年
2024年 | 167篇 |
2023年 | 416篇 |
2022年 | 817篇 |
2021年 | 747篇 |
2020年 | 860篇 |
2019年 | 686篇 |
2018年 | 605篇 |
2017年 | 773篇 |
2016年 | 903篇 |
2015年 | 982篇 |
2014年 | 1482篇 |
2013年 | 1247篇 |
2012年 | 1591篇 |
2011年 | 1697篇 |
2010年 | 1046篇 |
2009年 | 1045篇 |
2008年 | 812篇 |
2007年 | 779篇 |
2006年 | 604篇 |
2005年 | 425篇 |
2004年 | 307篇 |
2003年 | 301篇 |
2002年 | 229篇 |
2001年 | 208篇 |
2000年 | 190篇 |
1999年 | 151篇 |
1998年 | 119篇 |
1997年 | 95篇 |
1996年 | 79篇 |
1995年 | 71篇 |
1994年 | 57篇 |
1993年 | 53篇 |
1992年 | 46篇 |
1991年 | 36篇 |
1990年 | 24篇 |
1989年 | 25篇 |
1988年 | 25篇 |
1987年 | 10篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 25篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 3篇 |
1980年 | 7篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1959年 | 1篇 |
1951年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
基于涡串唯象概念和分形理论,建立了能够表达湍流多尺度结构物理特性的分形湍流化学反应模型,针对Steckler室内燃烧过程进行了数值模拟研究.湍流流动采用浮力修正的κ-ε双方程模型来模拟,辐射由Rosseland模型描述,整个模拟过程由ANSYS-CFX10.0实现.将模拟结果与Steckler的燃烧实验数据进行对比,并与EDC燃烧模型及文献中EBU燃烧模型的模拟结果进行对比.结果表明,FM燃烧模型模拟得出的温度、速度场分布与实验数据能够较好地吻合,是一种有前途的湍流化学反应模拟方法. 相似文献
82.
垃圾焚烧管式布风流化床的冷态实验 总被引:3,自引:1,他引:3
在床截面为300mm×300mm、床高为4. 4m的管式布风流化床实验台上,分别对宽筛分下不同颗粒粒度、不同床层高度、不同截面流速、布风的均匀性以及非平衡布风时颗粒流化特性进行实验研究,为未来垃圾衍生燃料的流化燃烧实验提供基础数据。管式布风流化床的开孔方向与夹角大小对床层压降变化影响明显,向下开孔角度越小,动能消耗越大,但床层稳定性能好。随着料层高度增加,各布风管间的布风更趋于平衡,流化的稳定与均匀性能也越好。管组压降失衡时,床层压降不平衡明显增加,波动幅度增大,不稳定性明显高于正常流化状态。 相似文献
83.
84.
85.
Heat transfer characteristics for a falling turbulent liquid film flow over a fin are analyzed using the conjugate convection-conduction theory. Numerical results are obtained from a simultaneous solution of the energy equations of the fluid and the fin. Results are presented for the fin temperature distribution, dimensionless heat transfer coefficients, local heat fluxes, and fin efficiencies. 相似文献
86.
因为制冷设计不合理,施工不专业,都会影响数据中心机房的制冷效率。该文介绍三种数据机房的高效制冷方法:按需制冷;水平送风;封闭冷通道。研究数据机房的高效制冷,不仅是节能减排的需要,也是保障数据机房稳定运行的需要。 相似文献
87.
The combustion of single bituminous char particles (4-12 mm diameter) was studied in a turbulent fluidized bed operated at 1098 K using air as the fluidising medium. Results indicated that particles burn with constant density following a shrinking sphere model. Burning rates are much higher than those observed in a bubbling fluidized bed. The rate of transfer of oxygen to the particle surface is also higher than that observed in bubbling beds. A model is proposed to calculate the Sherwood numbers of the burning carbon particles. Experimental values of the Sherwood numbers agree well with those predicted from the model. 相似文献
88.
A Numerical Sirnulation of Gas-Particle Two-Phase Flow in a Suspension Bed Using DifFusion Flux Model
下载免费PDF全文
![点击此处可从《中国化学工程学报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A mathematical modei of two-dimensional turbulent gas-particle twophase flow based on the modified diffusion flux modei (DFM) and a numerical simulation method to analyze the gas-particle flow structures are developed. The modified diffusion flux modei, in which the acceleration due to various forces is taken into account for the calculation of the diffusion velocity of particles, is applicable to the analysis of multi-dimensional gas-particle two-phase turbulent flow. In order to verify its accuracy and efficiency, the numerical simulation by DFM is compared with experimental studies and the prediction by k-ε-kp two-fluid modei, which shows a reasonable agreement. It is confirmed that the modified diffusion flux modei is suitable for simulating the multi-dimensional gas-particle two-phase flow. 相似文献
89.
Response to walnut olfactory and visual cues by the parasitic wasp Diachasmimorpha juglandis 总被引:2,自引:0,他引:2
Diachasmimorpha juglandis is a specialist parasitoid attacking fly larvae in the genus Rhagoletis that feed exclusively on walnut fruit husks. In a free-foraging assay comparing response to uninfested, infested, and mechanically damaged fruits, we first determined that D. juglandis use host feeding damage on the fruit as a cue for host presence. In another free-foraging assay that used artificial walnut models and wind tunnel experiments, D. juglandis distinguished infested from uninfested fruits by using either olfactory or visual cues separately. However, the response rate of wasps in the wind tunnel was raised considerably when visual cues were also available. We analyzed the volatile compounds emitted by cohorts of uninfested, mechanically damaged, and infested fruits 1, 3, 5, 8, and 10 days after oviposition by flies into the infested fruits. Total volatile emissions did not differ significantly among treatments, but quantitative changes in volatiles distinguished infested fruits from uninfested and damaged fruits. The fact that parasitoids did not distinguish between infested and damaged fruits in assays where damage was visible indicates that they rely on visual cues when those are available. 相似文献
90.
The ablation rate of frozen mixtures of water or wax with finely divided solids subjected to a turbulent axisymmetric water jet was investigated both experimentally and theoretically. The range of the water jet Reynolds number was 8700–29300 and the jet temperature varied between 22 and 60°C. The solids used were very fine kaolinite clay, titanium oxide and aluminium powder. The type of solids and their concentration were found to affect the ablation rate of ice-solids and wax-solids mixtures. This is mainly due to changes in the physical properties of the melt layer of the water-solids or wax-solids mixtures which forms between the impinging jet and the frozen mixtures. 相似文献