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451.
452.
An analogue/digital hybrid interface is presented that allows the support of simulations on an analogue computer EAI 380 by a microcomputer PDP 11/34. On this simulation system the peak spreading process of a Chromatographie column was implemented as an example for a simulation of a dynamic process in analytical chemistry. To implement the Chromatographie mass balance equations on the analogue part of the simulation system, only one hardwired stage of a cascade of reactors is necessary. The output values of one analogue simulation step were stored by the microcomputer as intermediate results and were given back as input values during the next analogue simulation step. The simulation process can be seen on a screen and is easily modified by online variation of the simulation parameters. 相似文献
453.
We measure the dynamic exponent of the three-dimensional Ising model using a damage spreading Monte Carlo approach as described by MacIsaac and Jan. We simulate systems fromL=5 toL=60 at the critical temperature,T
c
=4.5115. We report a dynamic exponent,z=2.35±0.05, a value much larger than the consensus value of 2.02, whereas if we assume logarithmic corrections, we find thatz=2.05±0.05. 相似文献
454.
It is discovered that there are two important characters, local-world character and weight-driven character, in many real-life complex networks. Motivated by this fact, a weight-driven local-world network model is proposed, which incorporates the weight dynamics and the fixed local-world property. By means of mathematical analysis and numerical simulation, the strength distribution of the network model has been obtained. The results are applied to epidemic spreading theory. 相似文献
455.
基于拉曼散射的光纤分布式温度测量系统的空间分辨力 总被引:5,自引:0,他引:5
基于自发拉曼散射的光纤分布式温度测量系统是一种真正的分布传感系统且已商品化。本文从光学的角度出发较详细地分析了此类系统的空间分辨力理论极限及其影响因素。分析表明, 对于一个1 km 的多模系统, 若接收机的最小可分辨光功率优于3.5 pW, 则其在0~400℃的范围内且温度精度为±1℃时的空间分辨力极限为2 cm ; 当接收机的最小可分辨光功率小于0.5 pW, 单模系统的空间分辨力极限优于对应的多模系统。因此, 把基于自发拉曼散射机理的光纤分布式温度测量系统用于短距离高分辨力的系统理论上是可行的。 相似文献
456.
驻区效应对激光大气传输的影响 总被引:1,自引:0,他引:1
对聚焦、转动束的驻区效应作了理论分析,并用激光大气传输四维程序作了校算。理论分析与程序计算结果均表明:在许多情况下,驻区效应的影响并不严重, 原因是驻区长度上的激光束热畸变数不大,热畸变扩束半径小于衍射扩束半径。 相似文献
457.
We study a network of m identical excitatory cells projecting excitatory synaptic connections onto a single inhibitory interneuron, which is reciprocally coupled to all excitatory cells through inhibitory synapses possessing short-term synaptic depression. We find that such a network with global inhibition possesses multiple stable activity patterns with distinct periods, characterized by the clustering of the excitatory cells into synchronized sub-populations. We prove the existence and stability of n-cluster solutions in a m-cell network. Using methods of geometric singular perturbation theory, we show that any n-cluster solution must satisfy a set of consistency conditions that can be geometrically derived. We then characterize the basin of attraction of each solution. Although frequency dependent depression is not necessary for multistability, we discuss how it plays a key role in determining network behavior. We find a functional relationship between the level of synaptic depression, the number of clusters and the interspike interval between neurons. This relationship is much less pronounced in the absence of depression. Implications for temporal coding and memory storage are discussed. 相似文献
458.
In this paper, we fabricated a TiO2 mesh with ultra-fast spreading superhydrophilic property without UV irradiation. Through electrospinning process followed by calcinations, we obtained meshes with special micropores and nanochannels composite hierarchical structures. Each fiber exhibits a bundle structure of aligned elementary filaments with nanochannels, which should be resulted from phase separation and stretch of electrostatic force during electrospinning process. The mesh shows ultra-fast spreading property within only tens of milliseconds (ms). It is concluded that the special topography offered a multi-scale 3D capillary effect that play crucial role in ultra-fast spreading superhydrophilic property of the mesh. This study provides interesting insights to design novel materials concerning liquid transport and dissipation, which may find its way in various applications. 相似文献
459.
We propose a model of mobile agents to study the epidemic spreading in communities with different densities of agents, which aims to simulate the realistic situation of multiple cities. The model addresses the epidemic process from a community with threshold λc1 less than the infection rate λ to a community with threshold λc2 larger than λ through both direct and indirect contacts. By both theoretic analysis and numerical simulations we show that it is possible to sustain the epidemic spreading in the community with λc2 through contact with another community, provided that the latter is connected with an infected community. This result suggests that for effectively controlling the epidemic spread, we should also pay attention to the risk caused by the infection through indirect contact. 相似文献
460.