全文获取类型
收费全文 | 3411篇 |
免费 | 209篇 |
国内免费 | 83篇 |
专业分类
电工技术 | 248篇 |
综合类 | 260篇 |
化学工业 | 383篇 |
金属工艺 | 56篇 |
机械仪表 | 99篇 |
建筑科学 | 1027篇 |
矿业工程 | 64篇 |
能源动力 | 194篇 |
轻工业 | 90篇 |
水利工程 | 231篇 |
石油天然气 | 89篇 |
武器工业 | 10篇 |
无线电 | 158篇 |
一般工业技术 | 130篇 |
冶金工业 | 127篇 |
原子能技术 | 22篇 |
自动化技术 | 515篇 |
出版年
2024年 | 9篇 |
2023年 | 28篇 |
2022年 | 56篇 |
2021年 | 76篇 |
2020年 | 69篇 |
2019年 | 32篇 |
2018年 | 58篇 |
2017年 | 84篇 |
2016年 | 89篇 |
2015年 | 103篇 |
2014年 | 182篇 |
2013年 | 178篇 |
2012年 | 219篇 |
2011年 | 296篇 |
2010年 | 201篇 |
2009年 | 234篇 |
2008年 | 239篇 |
2007年 | 289篇 |
2006年 | 250篇 |
2005年 | 175篇 |
2004年 | 156篇 |
2003年 | 140篇 |
2002年 | 114篇 |
2001年 | 69篇 |
2000年 | 69篇 |
1999年 | 59篇 |
1998年 | 45篇 |
1997年 | 39篇 |
1996年 | 33篇 |
1995年 | 25篇 |
1994年 | 22篇 |
1993年 | 14篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有3703条查询结果,搜索用时 15 毫秒
1.
分析了乐滩灌区工程北干渠溯河隧洞段长约1.06 km穿合山煤矿采空区的地质情况.借鉴高速公路煤矿采空区的成功处理经验,通过科学分析,对采空区变形和区域内覆岩的稳定性做了评价,论述了输水线路穿采空区段采取全充填压力注浆法的工程处理方法. 相似文献
2.
This paper presents an efficient method which provides the optimal generation mix and the optimal generation construction process. The approximation method in which the dynamic programming technique and gradient method are combined is applied to determine the optimal generation mix with hydropower generation technologies. The successive approximations dynamic programming (SADP) technique, which is very suitable for high-dimensional multistage decision process problems, is used for obtaining the optimal generation construction process. The effectiveness and feasibility of the developed technique are demonstrated on a practical power system model which has five types of generation technologies including a hydropower generation technology. 相似文献
3.
Since demand for power exhibits great variability the amount of firm energy to be purchased to meet real time demand based on forecasts is usually different from the realized demand for that period. The role of generation reserves is to meet the real time fluctuations of power demand. The predictable part of the demand is met through purchases of firm energy. In this paper a model is presented to determine optimal quantities of firm energy and generation reserves to meet random demands. The model is then parameterized introducing a set of factors to perform a sensitivity study. A full factorial experiment is designed to study the impact of five factors on the response variable (i.e., proportion of generation reserves on the total purchased quantity). An example consisting of 640 simulations corresponding to 25 treatment combinations evaluated over 20 randomly generated mean demands is used to identify significant factors on the response variable. Results from the experiment suggest that generation reserve requirements should be adjusted considering changes in significant factors and in the mean demand over the dispatch interval. 相似文献
4.
本文针对美孚油回收液与兰炼8#油混合利用进行可行性实验研究,经过重度、粘度、可燃性等方面的实验研究,表明美孚油回收液与兰炼8#油混合可以用在电动轮上并且获得良好的效果。 相似文献
5.
本文在讨论了下一代信令转接点在满足传统信令网络功能的基础上,着重介绍了下一代的信令转接点上实现的号码携带、灵活路由等新业务,并如何实现传统STP面向下一代网络的平滑过渡。 相似文献
6.
The Steady radial distribution of chemical species in a wire‐to‐cylinder ozone generator filled with pure oxygen has been computed by applying four different plasma chemistry models of increasing complexity. The most complete model considers ten species (e, O2 +, O2 ?, O3 ?, O?, O2, O2(1Δg), O2(1∑g +), O and O3) and 79 reactions, including ionization by electron impact, electron attachment and detachment, electron-ion recombination, charge transfer, etc. The chemical model is coupled with the electrical model through Poisson's equation. The spatially averaged ozone density has been computed as a function of the current intensity and compared with the experimental values obtained by UV spectroscopy. 相似文献
7.
The primary purpose of this paper is to show an efficient way of handling models and model data in a decision support system, in which it is usual to consider several variants of a model. The model data primarily consist of model-defining data, but the same approach may be used for the generated results as well. By efficient handling is meant the handling by the computer as well as by the user. For the user it is particularly important that new models can be conveniently defined as variants of existing models. The approach is introduced within the context of a decision support system for manpower planning based on Markov models. In the mean time the same approach has been used for the implementation of other decision support systems and has been found to be more generally applicable. 相似文献
8.
9.
Daniel Westln 《Progress in Nuclear Energy》2007,49(8):597-605
Stockpiles of spent nuclear fuel and weapons material are growing worldwide. So far, the only long-term strategy seriously considered is geological repository for several hundred thousand years. Transmutation is an option significantly reducing the time during which repositories have to be sealed, simplifying the task of protecting future generations from the radioactive remnants of our civilisation. This paper gives an overview of motives and priorities, and describes the main technique suggested for transmutation of nuclear waste. 相似文献
10.
本文详细地阐述了闪速炉冶炼过程烟灰发生的原因以及不利影响 ,并积极地寻求降低烟灰发生率的有效措施 ,具有实际操作意义。 相似文献