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991.
992.
This paper focuses on the exponential synchronization problem of complex dynamical networks (CDNs) with time-varying inner coupling via distributed event-triggered transmission strategy. Information update is driven by properly defined event, which depends on the measurement error. Each node is described as a second-order nonlinear dynamic system and only exchanges information with its neighboring nodes over a directed network. Suppose that the network communication topology contains a directed spanning tree. A sufficient condition for achieving exponential synchronization of second-order nonlinear systems in CDNs with time-varying inner coupling is derived. Detailed theoretical analysis on exponential synchronization is performed by the virtues of algebraic graph theory, distributed event-triggered transmission strategy, matrix inequality and the special Lyapunov stability analysis method. Moreover, the Zeno behavior is excluded as well by the strictly positive sampling intervals based on the upper right-hand Dini derivative. It is noted that the amount of communication among network nodes and network congestion have been significantly reduced so as to avoid the waste of network resources. Finally, a simulation example is given to show the effectiveness of the proposed exponential synchronization criteria. 相似文献
993.
本文基于第一性原理方法采用密度泛函理论研究了单层MoS_2吸附Cu_3,Ag_3,Au_3团簇的稳定性、能带结构和态密度.通过研究发现单层MoS_2在S位吸附Cu_3,Ag_3,Au_3团簇稳定性强于在Mo位吸附;Cu_3,Ag_3,Au_3团簇在单层MoS_2表面吸附产生3条杂质能级,分别是Cu、Ag、Au原子与S形成共价键下的形成了施主能级与受主能级;Cu,Ag、Au拥有良好的金属性致使单层MoS_2向导体转变.吸附体系的态密度在低能区主要来源于S的3s、Mo的5s以及Cu、Ag、Au的3d、4d、5d轨道的贡献;能量值在-7.5eV~-1eV范围内Cu、Ag、Au的d轨道与S的p发生杂化,形成了较高的态密度峰值.费米能附近的电荷分布主要于Mo-S、Cu-S、Ag-S、Au-S的成键方向. 相似文献
994.
Fuwang Zhang Lingling Xu Jinsheng Chen Xiaoqiu Chen Zhenchuan Niu Tong Lei Chunming Li Jinping Zhao 《Particuology》2013,11(3):264-272
Atmospheric fine particles (PM2.5) were collected in this study with middle volume samplers in Fuzhou, China, during both normal days and haze days in summer (September 2007) and winter (January 2008). The concentrations, distributions, and sources of polycyclic aromatic hydrocarbons (PAHs), organic carbon (OC), elemental carbon (EC), and water soluble inorganic ions (WSIIs) were determinated. The results showed that the concentrations of PM2.5, PAHs, OC, EC, and WSIIs were in the orders of haze > normal and winter > summer. The dominant PAHs of PM2.5 in Fuzhou were Fluo, Pyr, Chr, BbF, BkF, BaP, BghiP, and IcdP, which represented about 80.0% of the total PAHs during different sampling periods. The BaPeq concentrations of ∑PAHs were 0.78, 0.99, 1.22, and 2.43 ng/m3 in summer normal, summer haze, winter normal, and winter haze, respectively. Secondary pollutants (SO42?, NO3?, NH4+, and OC) were the major chemical compositions of PM2.5, accounting for 69.0%, 55.1%, 63.4%, and 64.9% of PM2.5 mass in summer normal, summer haze, winter normal, and winter haze, respectively. Correspondingly, secondary organic carbon (SOC) in Fuzhou accounted for 20.1%, 48.6%, 24.5%, and 50.5% of OC. The average values of nitrogen oxidation ratio (NOR) and sulfur oxidation ratio (SOR) were higher in haze days (0.08 and 0.27) than in normal days (0.05 and 0.22). Higher OC/EC ratios were also found in haze days (5.0) than in normal days (3.3). Correlation analysis demonstrated that visibility had positive correlations with wind speed, and negative correlations with relative humidity and major air pollutants. Overall, the enrichments of PM2.5, OC, EC, SO42?, and NO3? promoted haze formation. Furthermore, the diagnostic ratios of IcdP/(IcdP + BghiP), IcdP/BghiP, OC/EC, and NO3?/SO42? indicated that vehicle exhaust and coal consumption were the main sources of pollutants in Fuzhou. 相似文献
995.
996.
Numerical analysis of high Mach flow and flow reversal in the experimental advanced superconducting tokamak divertor 下载免费PDF全文
The B2-Eirene (SOLPS 4.0) code package is used to investigate the plasma parallel flow, i.e., the scrape-off layer (SOL) flow, in the experimental advanced superconducting tokamak (EAST) divertor. Simulation results show that the SOL flow in the divertor region can exhibit complex behaviour, such as a high Mach flow and flow reversal in different plasma regimes. When the divertor plasma is in the detachment state, the high Mach flow with approaching or exceeding sonic speed is observed away from the target plate in our simulation. When the divertor plasma is in the high recycling state, the flow reversal with a small Mach number (|M|< 0.2) is observed near the X-point along the separatrix region. The driving mechanisms for the high Mach flow and the reversed flow are analysed theoretically through momentum and continuity equations, respectively. The profile of the ionization sources is shown to be a possible formation condition causing the complex behaviour of the SOL flow. In addition, the effects of the high Mach flow and the flow reversal on the impurity transport are also discussed in this paper. 相似文献
997.
The Ghost Cell Method and Its Applications for Inviscid Compressible Flow on Adaptive Tree Cartesian Grids 下载免费PDF全文
In this paper, an immersed boundary algorithm is developed by
combining the ghost cell method with adaptive tree Cartesian grid
method.
Furthermore, the proposed method is successfully used to
evaluate various
inviscid compressible flow with immersed boundary.
The extension to three
dimensional cases is also achieved. Numerical
examples demonstrate the proposed method is effective. 相似文献
998.
羧脒盐桥介导的萘-二苯酮单重态能量传递研究 总被引:1,自引:0,他引:1
设计构建了以羧脒盐桥联接的二苯酮和萘超分子体系, NA-(脒基-羧基)-BP和NA-(羧基-脒基)-BP, 以及相应的模型体系. 稳态和时间分辨荧光光谱研究表明, 置于羧脒盐桥两端的萘和二苯酮基团之间可以发生有效的单重态能量传递, 超分子体系NA-(脒-羧)-BP (NA-Am/BP-COOH=1/1)和NA-(羧-脒)-BP (NA-COOH/BP-Am=1/1)中单重态能量传递效率分别为0.998和0.970, 速率常数分别为6.8×1010和1.5×1010 s-1. 推断羧脒盐桥介导了超分子体系中单重态能量传递过程并具备方向性性质, 单重态能量传递“通过键”以电子交换机制进行. 相似文献
999.
The analytical transfer matrix method (ATMM) is applied to
calculating the critical radius $r_{\rm c}$ and the dipole
polarizability $\alpha_{\rm d}$ in two confined systems: the hydrogen
atom and the Hulth\'{e}n potential. We find that there exists a
linear relation between $r_{\rm c}^{1/2}$ and the quantum number $n_{r}$
for a fixed angular quantum number $l$, moreover, the three bounds
of $\alpha_{\rm d}$ ($\alpha_{\rm d}^{K}$, $\alpha_{\rm d}^{B}$,
$\alpha_{\rm d}^{U}$) satisfy an inequality:
$\alpha_{\rm d}^{K}\leq\alpha_{\rm d}^{B}\leq\alpha_{\rm d}^{U}$. A comparison
between the ATMM, the exact numerical analysis, and the variational
wavefunctions shows that our method works very well in the systems. 相似文献
1000.
An ingenious approach of determining hydrogen isotope solubilities, diffusivities and permeabilities in GWHER-1 stainless steel 总被引:1,自引:0,他引:1 下载免费PDF全文
In this paper, by using an ingenious method, the hydrogen isotope solubilities and diffusivities in GWHER-1 stainless steel have been determined by a vacuum heating degassing approach at the temperature range of 597-1022 K on a set of specimens with different sizes previously charged for 24 h under a hydrogen isotope pressure of 105 Pa in the temperature range of 800-1000 K. The permeabilities are then derived from the relation Φ = DKs. It is found D = 1.52 ×10^-6exp(-54100/RT), Ks = 2.2×10^-exp(-5400/RT) and Φ = 3.3 ×10^-12exp(-59500/RT) for hydrogen, where Ks (Sieverts' constant) is given in Pa^-1/2, D in m2.s^-1.Pa^-1/2, T in K and R=8.31 J.mol^-1.K^-1. By taking isotope effects into account, the corresponding Arrhenius relations for deuterium and tritium are also deduced. 相似文献