全文获取类型
收费全文 | 859篇 |
免费 | 108篇 |
国内免费 | 83篇 |
专业分类
电工技术 | 22篇 |
综合类 | 85篇 |
化学工业 | 15篇 |
金属工艺 | 48篇 |
机械仪表 | 35篇 |
建筑科学 | 331篇 |
矿业工程 | 196篇 |
能源动力 | 16篇 |
轻工业 | 3篇 |
水利工程 | 176篇 |
石油天然气 | 6篇 |
武器工业 | 3篇 |
无线电 | 33篇 |
一般工业技术 | 47篇 |
冶金工业 | 10篇 |
自动化技术 | 24篇 |
出版年
2024年 | 6篇 |
2023年 | 20篇 |
2022年 | 28篇 |
2021年 | 42篇 |
2020年 | 37篇 |
2019年 | 20篇 |
2018年 | 21篇 |
2017年 | 30篇 |
2016年 | 34篇 |
2015年 | 42篇 |
2014年 | 64篇 |
2013年 | 46篇 |
2012年 | 80篇 |
2011年 | 73篇 |
2010年 | 61篇 |
2009年 | 48篇 |
2008年 | 53篇 |
2007年 | 59篇 |
2006年 | 54篇 |
2005年 | 39篇 |
2004年 | 42篇 |
2003年 | 38篇 |
2002年 | 33篇 |
2001年 | 11篇 |
2000年 | 14篇 |
1999年 | 9篇 |
1998年 | 11篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
排序方式: 共有1050条查询结果,搜索用时 15 毫秒
81.
《岩石力学与岩土工程学报(英文版)》2022,14(4):1200-1209
With complex topographic and hydrological characteristics, the landslide-induced surge disaster chain readily develops in mountainous and gorge areas, posing a huge challenge for infrastructure construction. This landslide-induced surge disaster chain involves a complex fluid-solid coupling between the landslide mass and a water body and exhibits complex energy conversion and dissipation characteristics, which is challenging to deal with using traditional finite element analysis. In this study, the energy evolution characteristics in the whole process of the disaster chain were first investigated, and the momentum-conservation equations for different stages were established. Then, the two-phase double-point material point method (TPDP-MPM) was used to model the landslide-induced surge disaster chain, and an experiment involving block-induced surge was modeled and simulated to validate this method. Finally, three generalized models were established for the landslide-induced surge process in a U-shaped valley, including subaerial, partly submerged, and submarine scenarios. The interaction mechanism between the landslide mass and the water body in the disaster chain was revealed by defining the system energy conversion ratio and the mechanism of evolution of the disaster chain from the perspective of energy. The results help further evaluate the secondary disasters, given the submerged position of the landslide mass. 相似文献
82.
83.
首先收集了17个U型金属阻尼器的试验数据,并对采用不同类型钢材的U型金属阻尼器的面内受力性能进行了分析和比较。在此基础上,研究了分别适用于构件层次分析和结构层次分析的U型金属阻尼器精细有限元模型和简化有限元模型的建模方法。结果表明:采用实体单元建立的精细有限元模型,既可较准确地模拟出U型金属阻尼器的荷载-位移滞回关系,又可以较好地反映其微观损伤模式;建议的U型金属阻尼器初始刚度和屈服荷载计算公式预测值与试验结果较接近,且偏于安全,可用于简化模型骨架参数的确定;采用建议的简化有限元模型分析得到的试件荷载-位移滞回曲线与试验结果吻合较好。 相似文献
84.
针对窄煤柱煤巷掘进完成初期出现的大变形控制难题,结合窄煤柱煤巷动静支承压力基本认识,运用CT扫描技术系统研究了窄煤柱煤巷巷道中心轴两侧煤体微裂隙的演化进程,提出双锚索桁架与单体锚索平行布置非对称支护技术,并对其组成结构、控制机理、应力场分布规律进行了系统研究。结果表明:1)窄煤柱煤巷巷道中心轴两侧煤体微裂隙数量、发育速度和贯通速度具有明显的不对称性;2)顶板和煤柱帮桁架锚索应力场沿垂直方向呈"蝙蝠形"向岩体深部扩展,应力叠加区更大范围锚固体处于受压应力状态。双锚索桁架平行布置非对称支护技术在120210窄煤柱煤巷试验成功,巷道围岩在静态支承压力和动态支承压力作用期间变形协调一致,控制效果良好,研究成果对类似工程条件的支护设计具有一定的理论意义和实用价值。 相似文献
85.
86.
87.
In response to technical issues such as the ineffective noise reduction impact of balanced cage and single-seat control valves, the U-shaped noise reduction cage control valve is investigated and developed. In addition, its equal percentage flow properties and noise reduction impact are good, allowing it to effectively minimize the noise created by the change of fluid parameters of medium such as vapor, gas, and gas-liquid two-phase flow. The flow coefficient and flow properties were analyzed. The noise features of the medium air flow at small and large openings of 30% and 85% are simulated and analyzed, respectively. The pressure, velocity, and temperature of the inlet and outlet air, as well as the sound intensity maximum and sound power level maximum, are also analyzed with the opening curves. A small opening of 30% was selected, and the noise characteristics of cavitation generated by the medium water flow were simulated and analyzed. Together with the pressure and temperature change curves of the incoming water, the volume maxima and density minima of water are studied. The maximum sound intensity and sound power level of water are analyzed using the pressure and temperature curves of inlet water, as well as the cavitation coefficient and the degree of opening. The results of the trial for the pressure resistance of the valve body and the trial for the valve seat seal indicate that both the valve body strength and the valve seat seal meet the specifications. Comparing the noise trial results and simulation results reveals that the sound intensity and sound power level assessed by the trial and simulation are comparable, and the noise reduction impact of the control valve is positive. 相似文献
88.
结合实际工作经验,系统阐述了碳纤维布加固的设计与施工,通过分析提出了加固措施,从而达到对混凝土结构构件加固补强的目的,为碳纤维布在工程加固的实际应用中积累经验。 相似文献
89.
90.
简单介绍了如何采用14a号槽钢桁架进行钢筋混凝土重力式桥台模板加固,具体阐述了该技术的施工方法,从而使重力式桥台外露部分无穿墙螺栓,确保重力式桥台的混凝土外观质量,同时为重力式桥台施工提供了实践经验。 相似文献