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991.
The Isodyne technique based on the scattered light scanning from a thin laser beam can be used to obtain the information inside
the loaded object in the room temperature nondestructively, so it is a very powerful technique in 3D stress analysis. The
problems are how to interpret the information and how to get sufficient information from the few interference fringe. Birefringence
phase shift technique can distinguish the fringe orders automatically and enrich the information in 256 gray levels between
maxim and minim light intensity. In the paper the Isodyne birefringence phase shift method with an oblique incidence and equilibrium
equation is presented, by which the 3D stresses in the middle plane of a plate with U shape notch are separated successfully.
The project supported by the National Natural Science Foundation of China under the Grant No. 1380345 相似文献
992.
弹性动力学反问题的发展和展望 总被引:3,自引:1,他引:3
本文介绍了弹性动力学反问题的理论和方法及其在工程实际中的应用。对本学科的当前发展,重点介绍了Born近似的线性化方法和利用弹性波的层析成象技术的理论基础,同时对一些实验技术作了简要介绍。对本学科的进一步发展值得注意解决的问题作了展望。 相似文献
993.
994.
M. A. Gschwendtner 《Heat and Mass Transfer》2004,40(6-7):561-572
The heat transfer from a rotating cylinder in an air-cross flow was investigated by purely optical measuring techniques. Flow velocities were measured by a two-dimensional LDV both in the vicinity of the cylinder and in the boundary layer. A new optical device based on light-deflection in a temperature field was developed to examine local temperature gradients in the boundary layer of the rotating cylinder. Finally, a Michelson-interferometer was installed to produce real-time pictures of isothermal lines around the heated cylinder. The impact of rotation on flow patterns, boundary layer behaviour and heat transfer could be clearly identified. It appears that the velocity-ratio acts like an independent parameter, in that flow patterns correspond to this dimensionless number. Furthermore, it seems that rotation dominates over cross flow, both fluid-dynamically and thermally above = 2.This work was carried out at the University of the Federal Armed Forces in Munich/Germany. 相似文献
995.
A method of stress—strain analysis of elastoplastic bodies with large displacements, rotations, and finite strains is developed.
The incremental loading technique is used within the framework of the arbitrary Lagrangian—Eulerian formulation. Constitutive
equations are derived which relate the Jaumann derivative of the Cauchy—Euler stress tensor and the strain rate. The spatial
discretization is based on the FEM and multilinear three-dimensional isoparametric approximation. An algorithm of stress—strain
analysis of elastic, hyperelastic, and perfectly plastic bodies is given. Numerical examples demonstrate the capabilities
of the method and its software implementation
__________
Translated from Prikladnaya Mekhanika, Vol. 41, No. 6, pp. 36–43, June 2005. 相似文献
996.
The results of an experimental investigation of the hydraulic resistance of a circular pipe for turbulent flow with periodic flow rate fluctuations are presented. The presence of resonance phenomena in the pipe is revealed. It is established that, for hydrodynamic nonstationarity, the pipe resistance is a nonmonotonous function of the frequency of the imposed flow rate fluctuations and differs from the pipe resistance in the stationary flow regime. Under the conditions considered, to find the pipe resistance it is necessary to take into account the variation of the flow kinetic energy with respect to the phase of the imposed flow rate fluctuations due to the deformation of the velocity profile. 相似文献
997.
Dong‐Gyu Lee Ohhun Gwon Han‐Saem Park Su Hwan Kim Juchan Yang Prof. Sang Kyu Kwak Prof. Guntae Kim Prof. Hyun‐Kon Song 《Angewandte Chemie (International ed. in English)》2015,54(52):15730-15733
The electric conductivity‐dependence of the number of electrons transferred during the oxygen reduction reaction is presented. Intensive properties, such as the number of electrons transferred, are difficult to be considered conductivity‐dependent. Four different perovskite oxide catalysts of different conductivities were investigated with varying carbon contents. More conductive environments surrounding active sites, achieved by more conductive catalysts (providing internal electric pathways) or higher carbon content (providing external electric pathways), resulted in higher number of electrons transferred toward more complete 4e reduction of oxygen, and also changed the rate‐determining steps from two‐step 2e process to a single‐step 1e process. Experimental evidence of the conductivity dependency was described by a microscopic ohmic polarization model based on effective potential localized nearby the active sites. 相似文献
998.
Prediction and simulation of wear response of Linz–Donawitz (LD) slag filled glass–epoxy composites using neural computation 下载免费PDF全文
This article reports on the implementation of a soft computing technique based on artificial neural networks (ANNs) in analyzing the wear performance of a new class of hybrid composites filled with Linz–Donawitz slag (LDS). LDS is a major solid waste generated in huge quantities during steel making. It comes from slag formers such as burned lime/dolomite and from oxidizing of silica, iron etc. while refining the iron into steel in the LD furnace. In this work, hybrid composites consisting of short glass fiber (SGF) reinforced epoxy filled with different LDS content (0, 7.5, 15 and 22.5 wt%) are prepared by simple hand lay‐up technique. Solid particle erosion trials, as per ASTM G 76 test standards, are conducted on the composite samples following a well‐planned experimental schedule based on Taguchi design of experiments. Significant process parameters predominantly influencing the rate of erosion are identified. The study reveals that the LDS content is the most significant among various factors influencing the wear rate of these composites. Further, a model based on ANN for the prediction of erosion performance of these composites is implemented. The ANN prediction profiles for the characteristic wear properties exhibit very good agreement with the measured results demonstrating that a well‐trained network has been created. The simulated results explaining the effect of significant process variables on the wear rate indicate that the trained neural network possesses enough generalization capability of predicting wear rate even beyond the experimental range. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
999.
Sabyasachi Kar Yu‐Shu Wang Wei‐Qi Li Xiu‐Dong Sun 《International journal of quantum chemistry》2015,115(22):1573-1579
The effect of plasma screening on the dynamic dipole polarizability (DPP) of two‐electron ions Be2+, B3+, and C4+ has been investigated using highly correlated exponential wave functions within the framework of pseudostate summation technique and Debye screening concept. Plasma‐screening effect on the oscillator strengths (OS) of the ultraviolet and visible series has also been investigated for the systems Li+, Be2+, B3+, C4+. The DPP are reported as functions of screening parameters. The OS for S‐P transitions are also reported for various screening parameters. The OS and dynamic polarizability show interesting behavior with increasing screening strength and nuclear charge. © 2015 Wiley Periodicals, Inc. 相似文献
1000.
The extrapolation scheme of correlation energy is revisited to evaluate the complete basis set limit from double‐zeta (DZ) and triple‐zeta levels of calculations. The DZ level results are adjusted to the standard asymptotic behavior with respect to the cardinal number, observed at the higher levels of basis sets. Two types of adjusting schemes with effective scaling factors, which recover errors in extrapolations with the DZ level basis set, are examined. The first scheme scales the cardinal number for the DZ level energy, while the second scheme scales the prefactor of the extrapolation function. Systematic assessments on the Gaussian‐3X and Gaussian‐2 test sets reveal that these calibration schemes successfully and drastically reduce errors without additional computational efforts. © 2015 Wiley Periodicals, Inc. 相似文献