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101.
以圆柱开槽波导、螺旋摇摆器为模型,考虑了电子初始速度零散、引导磁场等效应对放大器饱和特性的影响,导出了自洽的注波互作用三维非线性方程组.并在此基础上编制了相应的计算软件,通过数值分析的方法研究了圆柱开槽波导自由电子激光放大器的饱和效率、频带宽度等高频特性. 相似文献
102.
Numerical studies of atomic three-step photoionization processes with non-monochromatic laser fields 下载免费PDF全文
Xiao-Yong Lu 《中国物理 B》2022,31(6):63203-063203
The atomic selective multi-step photoionization process is a critical step in laser isotope separation. In this work, we study three-step photoionization processes with non-monochromatic laser fields theoretically based on the semi-classical theory. Firstly, three bandwidth models, including the chaotic field model, de-correlation model, and phase diffusion model, are introduced into the density matrix equations. The numerical results are compared with each other comprehensively. The phase diffusion model is selected for further simulations in terms of the correspondence degree to physical practice. Subsequently, numerical calculations are carried out to identify the influences of systematic parameters, including laser parameters (Rabi frequency, bandwidth, relative time delay, frequency detuning) and atomic Doppler broadening, on photoionization processes. In order to determine the optimal match among different systematic parameters, the ionization yield of resonant isotope, and selectivity factor are adopted as evaluation indexes to guide the design and optimization process. The results in this work can provide a rewarding reference for laser isotope separation. 相似文献
103.
用严格的场匹配方法分析了填充等离子体的耦合腔链,研究了等离子体 腔混合模的形成以及“冷带宽”和“热带宽”的展宽效应。等离子体填充周期性耦合腔链后,形成周期性的截止频率为0的等离子体TG模式。当填充的等离子体密度较大,且腔模和TG模式发生部分重叠时,两者相互耦合,形成等离子体 腔混合模式。工作在混合模式下,其“冷带宽”和“热带宽”大大增宽,且耦合阻抗比真空时提高了近5倍,因此在填充等离子体后,耦合腔链的慢波特性得到了显著的改善。 相似文献
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107.
Ana Maria Cardenas Soto Salvador Sales Maicas Jose Capmany 《Fiber and Integrated Optics》2004,23(2):109-120
In this article we propose a new methodology to estimate the change in the bandwidth demand in time, mainly in residential areas. The bandwidth demand forecast is a basic aspect to decide the evolution of metropolitan optical networks. The word evolution refers to the necessity of making changes in networks, either by upgrading or replacing different elements that are part of the network. This analysis, along with a technological alternatives analysis, provides the operator the needed information to achieve the appropriate network planning and to make investment decisions. 相似文献
108.
We consider a fluid model of a system that handles multiple classes of traffic. The delay and cell-loss requirements of the
different classes of traffic are generally widely different and are achieved by assigning different buffers for different
classes, and serving them in a strict priority order. We use results from the effective bandwidth of the output processes
(see Chang and Thomas (1995)) to derive simple and asymptotically exact call-admission policies for such a system to guarantee
the cell-loss requirements for the different classes assuming that each source produces a single class traffic. We compare
the admission-control policies developed here with the approximate policy studied by Elwalid and Mitra (1995) for the case
of two-class traffic.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
109.
Juhui Wei Zhangming He Jiongqi Wang Dayi Wang Xuanying Zhou 《Entropy (Basel, Switzerland)》2021,23(3)
Weak fault signals, high coupling data, and unknown faults commonly exist in fault diagnosis systems, causing low detection and identification performance of fault diagnosis methods based on statistics or cross entropy. This paper proposes a new fault diagnosis method based on optimal bandwidth kernel density estimation (KDE) and Jensen–Shannon (JS) divergence distribution for improved fault detection performance. KDE addresses weak signal and coupling fault detection, and JS divergence addresses unknown fault detection. Firstly, the formula and algorithm of the optimal bandwidth of multidimensional KDE are presented, and the convergence of the algorithm is proved. Secondly, the difference in JS divergence between the data is obtained based on the optimal KDE and used for fault detection. Finally, the fault diagnosis experiment based on the bearing data from Case Western Reserve University Bearing Data Center is conducted. The results show that for known faults, the proposed method has and higher detection rate than statistics and the cross entropy method, respectively. For unknown faults, statistics cannot effectively detect faults, and the proposed method has approximately higher detection rate than the cross entropy method. Thus, the proposed method can effectively improve the fault detection rate. 相似文献
110.
Boris S. Karasik William R. McGrath 《International Journal of Infrared and Millimeter Waves》1999,20(1):21-32
The impedance of the submillimeter superconducting hot-electron bolometer mixer was measured in the range 0.2-4 GHz. A special technique relying on determination of the S
21 transmission parameter of the device was used. Many advantages of the technique (wide frequency range, in situ calibration, low test power, accuracy) are demonstrated. The estimate of the mixer bandwidth from the impedance data using the mixer theory is in good agreement with the results of the direct bandwidth measurements. 相似文献