全文获取类型
收费全文 | 1092篇 |
免费 | 78篇 |
国内免费 | 20篇 |
专业分类
化学 | 166篇 |
晶体学 | 1篇 |
力学 | 43篇 |
综合类 | 3篇 |
数学 | 73篇 |
物理学 | 230篇 |
无线电 | 674篇 |
出版年
2024年 | 5篇 |
2023年 | 19篇 |
2022年 | 21篇 |
2021年 | 32篇 |
2020年 | 36篇 |
2019年 | 34篇 |
2018年 | 28篇 |
2017年 | 46篇 |
2016年 | 40篇 |
2015年 | 50篇 |
2014年 | 84篇 |
2013年 | 83篇 |
2012年 | 52篇 |
2011年 | 61篇 |
2010年 | 41篇 |
2009年 | 70篇 |
2008年 | 65篇 |
2007年 | 55篇 |
2006年 | 78篇 |
2005年 | 56篇 |
2004年 | 50篇 |
2003年 | 36篇 |
2002年 | 32篇 |
2001年 | 17篇 |
2000年 | 19篇 |
1999年 | 17篇 |
1998年 | 16篇 |
1997年 | 9篇 |
1996年 | 10篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1984年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有1190条查询结果,搜索用时 15 毫秒
101.
Alzheimer’s disease (AD) is a progressive neurodegenerative disease of central nervous system among elderly people. Human acetylcholinesterase (hAChE), an important enzyme in neuronal signaling, is responsible for the degradation of acetylcholine which in turn prevents the post synaptic signal transmissions. hAChE has been an attractive target of drug discovery for the search of therapeutics against AD. In the recent past hAChE has become hot target for the investigation of new potential therapeutics. We performed virtual screening of entire database against hAChE. Further, the extra precision molecular docking was carried out to refine the docking results and the best complex was passed for molecular dynamics simulations in order of understanding the hAChE dynamics and its behavior in complex with the ligand which corroborate the outcomes of virtual screening. This also provides binding free energy data that establishes the ligands efficiency for inhibiting hAChE. The computational findings discussed in this paper provide initial information of inhibitory effects of ligand, (drugbank entry DB00983), over hAChE. 相似文献
102.
Molecular dynamics with the stochastic process provides a convenient way to compute structural and thermodynamic properties of chemical, biological, and materials systems. It is demonstrated that the virtual dynamics case that we proposed for the Langevin equation[J. Chem. Phys. 147 , 184104 (2017)] in principle exists in other types of stochastic thermostats as well. The recommended "middle" scheme[J. Chem. Phys. 147 , 034109 (2017)] of the Andersen thermostat is investigated as an example. As shown by both analytic and numerical results, while the real and virtual dynamics cases approach the same plateau of the characteristic correlation time in the high collision frequency limit, the accuracy and efficiency of sampling are relatively insensitive to the value of the collision frequency in a broad range. After we compare the behaviors of the Andersen thermostat to those of Langevin dynamics, a heuristic schematic representation is proposed for understanding efficient stochastic thermostatting processes with molecular dynamics. 相似文献
103.
104.
The law of virtual work (VWL) is probably the first law in the history of mechanics; it is previous to the one on the lever, though not completely distinct from it. Here I will discuss the logical status of VWL, that is whether it is an autonomous principle or a theorem of some sort of mechanics. The problem is complicated by the fact that up to now no universally recognised expression has been accepted for it. From this article the problematical nature of VWL demonstrability is quite clear when the mechanics does not characterise completely the constraints. Italian schools in the XVIII century, even if we do not take Lagrange into consideration, had an important role, both in the development of VWL and in the discussion of its role. 相似文献
105.
Claude Valle Jean-Marie Souriau Gry de Saxc Danielle Fortun 《Comptes Rendus Mecanique》2004,332(12):1013-1018
We show that the affine structure of the 3-dimensional space is deeply enmeshed with the static laws expression. The relevance of tensorial rules for calculus in mechanics is thus enhanced. The virtual work principle is stated precisely but a little twist is given to the usual statements: the tensorial nature of the so-called virtual displacement vector is asserted to be covariant. To cite this article: C. Vallée et al., C. R. Mecanique 332 (2004).
Résumé
Nous montrons que la structure affine de l'espace tridimensionnel est fortement imbriquée avec l'expression des lois de la statique. La pertinence de l'application des règles du calcul tensoriel à la mécanique est ainsi renforcée. Le principe des travaux virtuels est établi précisément avec une seule entorse aux exposés classiques : la nature tensorielle de l'habituel vecteur déplacement virtuel est affirmée covariante. Pour citer cet article : C. Vallée et al., C. R. Mecanique 332 (2004). 相似文献106.
在虚拟现实系统实现过程中,水体的模拟是非常重要的部分。本文通过对水体特点进行剖析,比较、借鉴总结大量国内外研究成果及文献,深入地分析和研究了不同场景中的水体实时模拟绘制方法,提出了具有较高绘制效率和视觉效果的能够在PC机上实现的不同水体模型的绘制方法。 相似文献
107.
本课题应用虚拟仪器技术,采用LabVIEW 9.0作为开发工具,构建了一个适合高职电子专业学生远程使用的实验平台。文中重点讨论了远程实验平台的总体框架、实验项目的开发与集成、实验平台网络通信的实现方法。学生使用浏览器或“连接至远程前面板”方式完成实验。此种模式突破了传统实验的时空限制,对于充分利用教学资源、更大程度地实现资源共享具有重要意义。 相似文献
108.
根据摄像机在空中轨道的拍摄需求,设计了一种由伺服电机驱动摄像机实现俯仰摇移运动功能的控制系统。所设计控制系统的硬件包括伺服电机、无线数传模块和控制摇杆等相关设备,控制平台由基于LabVIEW2012开发的软件系统实现。通过仿真和实验证明,该控制系统具有定位准确、响应迅速、操作简单等特点,为实现摄像机在空中轨道的稳定拍摄提供了可靠保证。 相似文献
109.
针对目前我国高等学校普遍存在实验设备不足、型号落后、难以更新换代跟上科技发展的现象,虚拟现实技术的应用为高校实验教学提供了一个良好的解决方案。本文简单介绍了虚拟现实技术的特点,通过对虚拟现实实验教学系统的详细分析,探讨了虚拟现实技术对实验教学的影响。 相似文献
110.
This paper presents extended artificial physics optimization (EAPO), a population-based, stochastic, evolutionary algorithm (EA) for multidimensional search and optimization. EAPO extends the physicomimetics-based Artificial Physics Optimization (APO) algorithm by including each individual’s best fitness history. Including the history improves EAPO’s search capability compared to APO. EAPO and APO invoke a gravitational metaphor in which the force of gravity may be attractive or repulsive, the aggregate effect of which is to move individuals toward local and global optima. A proof of convergence is presented that reveals the conditions under which EAPO is guaranteed to converge. Discrete-time linear system theory is used to develop a second-order difference equation for an individual’s stochastic position vector as a function of time step. Stable solutions require eigenvalues inside the unit circle, leading to explicit convergence criteria relating the run parameters {mi, w, G}. EAPO is tested against several benchmark functions with excellent results. The algorithm converges more quickly than APO and with better diversity. 相似文献