全文获取类型
收费全文 | 700篇 |
免费 | 106篇 |
国内免费 | 70篇 |
专业分类
电工技术 | 33篇 |
综合类 | 102篇 |
化学工业 | 12篇 |
金属工艺 | 17篇 |
机械仪表 | 63篇 |
建筑科学 | 33篇 |
矿业工程 | 8篇 |
能源动力 | 5篇 |
轻工业 | 10篇 |
水利工程 | 16篇 |
石油天然气 | 14篇 |
武器工业 | 28篇 |
无线电 | 145篇 |
一般工业技术 | 68篇 |
冶金工业 | 9篇 |
原子能技术 | 12篇 |
自动化技术 | 301篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 17篇 |
2020年 | 18篇 |
2019年 | 27篇 |
2018年 | 27篇 |
2017年 | 35篇 |
2016年 | 41篇 |
2015年 | 37篇 |
2014年 | 50篇 |
2013年 | 43篇 |
2012年 | 67篇 |
2011年 | 57篇 |
2010年 | 43篇 |
2009年 | 47篇 |
2008年 | 46篇 |
2007年 | 66篇 |
2006年 | 38篇 |
2005年 | 25篇 |
2004年 | 32篇 |
2003年 | 30篇 |
2002年 | 23篇 |
2001年 | 19篇 |
2000年 | 20篇 |
1999年 | 16篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有876条查询结果,搜索用时 218 毫秒
1.
通过计算机模拟金属配合物与核酸作用机理,对其理论模型能量计算和结构优化。在不同的化学环境条件下得到不同的实验模拟结果,对真实的化学反应过程有重要的指导意义和参考意义。通过Gaussian03,Gauss View等软件的结合应用,分别应用于优化计算和理论建模,熟悉了对化学软件操作应用。 相似文献
2.
Didier Lemoine 《Computer Physics Communications》1996,97(3):331-344
A quantum wave packet code for studying nonreactive scattering of closed-shell atoms or diatomic molecules from a rigid surface is described. The time evolution relies on the Chebychev propagator. Up to 5 collider degrees of freedom, 3 in translation and 2 in rotation, are treated in a pseudospectral way with the momentum or finite basis representation as the primary space. Potential matrix elements are efficiently evaluated by means of sequential 1D transformations between momentum and coordinate spaces. Fast Fourier transforms are performed for the translational and azimuthal coordinates whereas a Gauss-Legendre transform is used for the polar coordinate. This pseudospectral strategy minimizes memory requirements because no off-diagonal Hamiltonian matrix elements need to be stored. In addition, a wide variety of physical systems can be studied since no particular functional form is imposed for the interaction potential. 相似文献
3.
多输入单输出逆高斯分布流域汇流模型 总被引:1,自引:0,他引:1
本文将逆高斯分布应用于由水库和区间组成的复杂的流域汇流系统,并建立了多输入单输出逆高斯单位线模型。讨论了模型参数的估计方法,并对沾益流域的雨洪资料进行了实例分析。 相似文献
4.
介绍带状大比例尺地形图在分带处高斯平面上拼接的原理和方法,并编制了相应的接边数据处理程序。作业实践说明,该接边方法简便实用,计算程序正确可靠。 相似文献
5.
《Journal of Process Control》2014,24(6):975-990
Soft sensor technology is an important means to estimate important process variables in real-time. Modeling for soft sensor system is the core of this technology. Most nonlinear dynamic modeling methods integrate the processes of building the dynamic and static relationships between secondary and primary variables, which limits the estimation accuracy for primary variables. To avoid the problem, a kind of soft sensor model consisting of a dynamic model in cascade with a static one is proposed. The model identification and update online are conducted in substep way. In order to improve the model update efficiency, two improved Gauss–Newton recursive algorithms, which avoid nonsingular covariance matrix, are proposed for time-invariant and time-variant soft sensor systems. The uniform convergence for dynamic model parameter and the existence of estimation deviations for static model parameters are proved for time-invariant soft sensor system. The parameters of time-variant soft sensor system would be boundedly convergent. Case study confirms that, on the basis of the proposed model and recursive algorithms, the dynamic and static characteristics of soft sensor system can be described efficiently, and the primary variables are ensured to be estimated accurately. 相似文献
6.
7.
Electromagnetic forces generated by the inter-action of component satellites can be used to release companion satellites. Optimal release trajectories for companion satellite system using inter-electromagnetic forces were investigated. Firstly, nonlinear relative motion dynamic equations of a two-craft electromagnetic companion satellite system were derived in spatial polar coordinates. Then principles of electromagnetic satellite formation flying were introduced. Secondly, the characteristics of the electromagnetic companion satellites release were analyzed and optimal release trajectories of companion satellites using electromagnetic forces were obtained using Gauss pseudospectral method. Three performance criteria were chosen as minimum time, minimum acceleration of the separation distance and minimum control acceleration. Finally, three release examples including expansion along separation distance, rotation in orbital plane and stable formation reconfiguration were given to demonstrate the feasibility of this method. Results indicated that the release trajectories can converge to optimal solutions effectively and the concept of release companion satellites using electromagnetic forces is practicable. 相似文献
8.
利用ANSYS有限元分析软件,根据钨极氩弧焊焊接特点,建立了高斯衰减热源模型,并在一定厚度、一定焊接工艺条件下对Monel-400合金板焊接温度场进行了模拟计算。模拟结果分析得到:利用高斯旋转热源在焊接过程中形成了长度为12 mm,宽度为7 mm,深度为5 mm的熔池。熔池上表面与下表面温度相差约620℃,热影响区节点温度随到焊缝中心距离的增加而不断减小。模拟结果表明改进后的热源模型与实际焊接较为吻合,有利于提高焊接温度场的模拟计算精度。 相似文献
9.
10.