全文获取类型
收费全文 | 2585篇 |
免费 | 270篇 |
国内免费 | 256篇 |
专业分类
电工技术 | 23篇 |
综合类 | 322篇 |
化学工业 | 114篇 |
金属工艺 | 64篇 |
机械仪表 | 22篇 |
建筑科学 | 1367篇 |
矿业工程 | 268篇 |
能源动力 | 29篇 |
轻工业 | 16篇 |
水利工程 | 387篇 |
石油天然气 | 50篇 |
武器工业 | 7篇 |
无线电 | 35篇 |
一般工业技术 | 141篇 |
冶金工业 | 151篇 |
原子能技术 | 1篇 |
自动化技术 | 114篇 |
出版年
2024年 | 7篇 |
2023年 | 15篇 |
2022年 | 49篇 |
2021年 | 51篇 |
2020年 | 68篇 |
2019年 | 69篇 |
2018年 | 50篇 |
2017年 | 82篇 |
2016年 | 67篇 |
2015年 | 90篇 |
2014年 | 171篇 |
2013年 | 137篇 |
2012年 | 231篇 |
2011年 | 192篇 |
2010年 | 167篇 |
2009年 | 200篇 |
2008年 | 192篇 |
2007年 | 173篇 |
2006年 | 148篇 |
2005年 | 187篇 |
2004年 | 135篇 |
2003年 | 141篇 |
2002年 | 102篇 |
2001年 | 75篇 |
2000年 | 64篇 |
1999年 | 54篇 |
1998年 | 43篇 |
1997年 | 29篇 |
1996年 | 26篇 |
1995年 | 24篇 |
1994年 | 17篇 |
1993年 | 12篇 |
1992年 | 14篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1980年 | 1篇 |
1979年 | 4篇 |
排序方式: 共有3111条查询结果,搜索用时 15 毫秒
1.
对爆炸效应在淤泥软基工程中的应用问题进行了探讨,并首次提出了爆炸在淤泥软基中的分界应力特征以及排水固结及破坏分区的基本模式。为采用动力加速对淤泥软基工程的处理,提供了试验依据,具有实用价值和指导意义。 相似文献
2.
3.
压密注浆及其在地基加固中的应用 总被引:1,自引:0,他引:1
在简单介绍了压密注浆工法的加固机理、影响被加固土体强度的因素的基础上,结合工程实例介绍了压缩注浆工法的工程应用情况。 相似文献
4.
本文研究了有新颖容性合并电路的MHD发电机在法拉第联接下输出特性,指出由于新颖容性合并电路具有工作点可调性,在合理的参数匹配下有平稳的输出特性;从而提出了含补偿电源的容性合并电路和MHD发电机外斜连方案。该方案具有斜连发电机的特征,又具有法拉第发电机高焓取出的优点,而且可减小阴极导电渣对发电机寿命的影响,是一种有发展前景的功率调节器方案。 相似文献
5.
V. V. Tcherdyntsev S. D. Kaloshkin A. I. Salimon E. A. Leonova I. A. Tomilin J. Eckert F. Schurack V. D. Rogozin S. P. Pisarev Yu. P. Trykov 《Materials and Manufacturing Processes》2002,17(6):825-841
Al-Cu-Fe alloys were prepared from elemental powders in a high-energy planetary ball mill. A sequence of solid state reactions resulting in quasicrystal (QC) phase formation takes place during heating of the as-milled powder. These reactions were studied by both differential scanning calorimetry and x-ray diffraction methods. Mechanically alloyed powders were consolidated by cold and hot pressing, as well as by explosive compaction. After annealing at sufficiently high temperatures, the consolidated samples are single-phase QC, except the ones consolidated by explosion. The high reactivity of the as-milled alloys causes the appearance of high porosity of the consolidated samples after the annealing. 相似文献
6.
介绍纽柯公司2002年的运作情况和做的几件大事:1)扩张与兼并;2)新工艺的采用;3)和外部的合作等。 相似文献
7.
The paper investigates the performance of various time stepping schemes for coupled displacement and pore pressure analysis.
A number of alternative forms of the automatic time stepping method proposed by Sloan and Abbo (1999a) are also presented.
These alternative schemes use different updates for the displacements and pore pressures and also adopt different starting
conditions for the iterations. The automatic schemes are compared with an implicit θ-method, as well as an explicit method,
through analysis of a variety of problems involving undrained loading, drained loading, and consolidation for Mohr-Coulomb
and critical state models. As expected, the numerical results confirm that the explicit scheme is neither accurate nor robust.
Although the implicit θ-method is accurate and fast, it fails to give a solution in a number of cases where the time step
is large. The automatic schemes are shown to be accurate, fast and generally robust. Two of the automatic schemes proposed
never fail to furnish a solution for the cases considered. In addition, all the automatic schemes are able to constrain the
time-stepping (temporal integration) error in the displacements and pore pressures to lie near a prescribed tolerance, provided
the iteration error tolerance is properly chosen. For complex soil models, it is important that the latter is set sufficiently
small in order for the schemes to be able to constrain the time-stepping error to lie within a prescribed tolerance.
Dedicated to the memory of Prof. Mike Crisfield, for his cheerfulness and cooperation as a colleague and friend over many
years. 相似文献
8.
Memory loss in retrograde amnesia has long been held to be larger for recent periods than for remote periods, a pattern usually referred to as the Ribot gradient. One explanation for this gradient is consolidation of long-term memories. Several computational models of such a process have shown how consolidation can explain characteristics of amnesia, but they have not elucidated how consolidation must be envisaged. Here findings are reviewed that shed light on how consolidation may be implemented in the brain. Moreover, consolidation is contrasted with alternative theories of the Ribot gradient. Consolidation theory, multiple trace theory, and semantization can all handle some findings well but not others. Conclusive evidence for or against consolidation thus remains to be found. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
采用声波测井、地震CT等综合物探方法 ,对正义峡水库坝址基础岩体固结灌浆质量进行检测 ,基本查明了坝基岩体固结灌浆后的质量状况 ,取得了良好的应用效果 相似文献
10.