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21.
22.
Young Hee Geum Young Ik Kim Kang Sup Lee 《Journal of Applied Mathematics and Computing》2007,25(1-2):109-118
A parametric boundary equation is established for the principal period-2 bulb in the cubic Mandelbrot set. Using its geometry, an efficient escape-time algorithm which reduces the construction time for the period-2 bulbs in the cubic Mandelbrot set is introduced and the implementation graphic results display the fascinating fractal beauty 相似文献
23.
We introduce the time-consistency concept that is inspired by the so-called “principle of optimality” of dynamic programming
and demonstrate – via an example – that the conditional value-at-risk (CVaR) need not be time-consistent in a multi-stage
case. Then, we give the formulation of the target-percentile risk measure which is time-consistent and hence more suitable
in the multi-stage investment context. Finally, we also generalize the value-at-risk and CVaR to multi-stage risk measures
based on the theory and structure of the target-percentile risk measure. 相似文献
24.
The notion of balanced bipartitions of the vertices in a tree T was introduced and studied by Reid (Networks 34 (1999) 264). Reid proved that the set of balance vertices of a tree T consists of a single vertex or two adjacent vertices. In this note, we give a simple proof of that result. 相似文献
25.
M.V. Nazarov J.H. Kang E.-J. Popovici B.S. Tsukerblat 《Solid State Communications》2005,133(3):183-186
Samples of yttrium oxide doped with trivalent europium have been prepared by ceramic techniques, under different synthesis conditions; barium chloride (BaCl2) and sodium tetraborate (Na2B4O7) were tested as flux. The improvement of luminescence properties in dependence on substitution of Eu3+ for Y3+ in the host lattice, under electron and UV excitations is demonstrated. The lattice parameter as a quantitative assessment of activator incorporation degree is proposed. The obtained results are discussed with respect to the employed processing method. 相似文献
26.
In this paper, based on the natural boundary reduction advanced by Feng and Yu, we couple the finite element approach with the natural boundary element method to study the weak solvability and Galerkin approximation of a class of nonlinear exterior boundary value problems. The analysis is mainly based on the variational formulation with constraints. We prove the error estimate of the finite element solution and obtain the asymptotic rate of convergence. Finally, we also give a numerical example.
相似文献27.
Jin-Mok Hur Chung-Seok Seo Sun-Seok Hong Dae-Seung Kang Seong-Won Park 《Reaction Kinetics and Catalysis Letters》2003,80(2):217-222
The concept of a novel electrochemical reduction process for the treatment of spent nuclear fuels in Li2O-LiCl molten salt was proposed and fresh tests using U3O8 powder were carried out to elucidate the reaction mechanism and verify the feasibility of the process. Electrolysis of Li2O and reduction of U3O8 powder took place simultaneously at the cathode part of the electrolysis cell via a catalytic EC mechanism and the conversion of U3O8 to U metal was more than 99%.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
28.
Hyun Chul Choi Min Kyu Lee Hyun Joon Shin Seung Bin Kim 《Journal of Electron Spectroscopy and Related Phenomena》2003,130(1-3):85-96
To investigate the formation of a solid electrolyte interface (SEI) on the Li1+xV3O8 electrode surface in the thermodynamic stability range of the organic electrolyte, we applied scanning photoelectron microscopy (SPEM) to a pristine electrode and to an electrode after ten cycles. The F K-edge absorption spectrum of the cycled electrode showed that LiF forms on the electrode surface during the lithium insertion–extraction process in the Li1+xV3O8/Li cell. The photoelectron spectrum for the cycled electrode showed intense spectral features corresponding to Li 1s, F 2s, F 2p, and P 2p electron signals, whereas these spectral features were of negligible intensity for the pristine electrode. The above results give strong support for the formation of an SEI that consists of LiF and compounds containing phosphorus during operation of the battery. The SPEM images also revealed that the fluorine distribution on the surface of the cycled electrode was inhomogeneous. 相似文献
29.
Green-light-emitting Zn2SiO4:Mn phosphor particles were synthesized by modified large-scale spray pyrolysis using a colloidal solution containing fumed silica particles. The particles had a fine size, filled morphology, spherical shape and non-aggregation characteristics even after post-treatment at 1150 °C. The luminescence characteristics of Zn2SiO4:Mn phosphor particles having spherical shape, such as brightness and decay time under VUV excitation light, were investigated as a function of Mn content. The luminescence intensity exhibits a maximum at 5 mol% Mn-doped powder. The decay time increases consistently with decreasing Mn content and more saturated color coordinates are obtained with the composition having 12 mol% Mn. As a consequence, the 10 mol% Mn-doped powder proved to provide a good combination of favorable luminance and acceptable decay time. The influence of post-treatment temperature on the decay time and photoluminescence characteristics of Zn2SiO4:Mn particles was also investigated. Particles post-treated at 1155 °C had the maximum photoluminescence intensity, which was identical to 113% that of the commercial product, and a comparable decay time of 5.8 ms. PACS 81.20.Rg; 78. 55.Hx; 78.40.Ha; 81.05.Hd; 81.40.Tv 相似文献
30.
Yong Joon Park Min Gyu KimYoung-Sik Hong Xianglan WuKwang Sun Ryu Soon Ho Chang 《Solid State Communications》2003,127(7):509-514
Li[NixLi(1/3−2x/3)Mn(2/3−x/3)]O2 (X=0.17, 0.25, 0.33, 0.5) compounds are prepared by a simple combustion method. The Rietvelt analysis shows that these compounds could be classified as having the α-NaFeO2 structure. The initial charge-discharge and irreversible capacity increases with the decrease of x in Li[NixLi(1/3−2x/3)Mn(2/3−x/3)]O2. Indeed, Li[Ni0.50Mn0.50]O2 compound shows relatively low initial discharge capacity of 200 mAh/g and large capacity loss during cycling, with Li[Ni0.17Li0.22Mn0.61]O2 and Li[Ni0.25Li0.17Mn0.58]O2 compounds exhibit high initial discharge capacity over 245 mAh/g and stable cycle performance in the voltage range of 4.8 -2.0 V. On the other hand, XANES analysis shows that the oxidation state of Ni ion reversibly changes between Ni2+ and about Ni3+, while the oxidation state of Mn ion sustains Mn4+ during charge-discharge process. This result does not agree with the previously reported ‘electrochemistry model’ of Li[NixLi(1/3−2x/3)Mn(2/3−x/3)]O2, in which Ni ion changes between Ni2+ and NI4+. Based on these results, we modified oxidation-state change of Mn and Ni ion during charge-discharge process. 相似文献