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981.
Nano-scale nickel hydroxide was prepared by precipitate transformation method in the paper. Effect of rinse pH on the agglomeration degree and electrochemical performance of nano-scale Ni (OH)2 was investigated. The measurement results of XRD and TEM indicate that the prepared nano-scale Ni (OH)2 is β (II)-phase, the grain size is in the rang of 10 ~ 50nm, and rinse pH exerts a great influence on the agglomeration degree of nano-scale Ni(OH) 2.The agglomeration of material becomes very obvious when rinse pH = 11, and the density of nano-scale Ni(OH)2 is enhanced obviously. Cyclic voltammetry(CV) and simulate cells experiment show that nano-scale Ni(OH)2 with suitable agglomeration degree have better electrochemical CV performance than those with ideal disperse Ni (OH)2and micron Ni(OH)2, and its proton diffusion coefficient is also the highest. It can elevate the discharge potential platform and prolongs discharge time, so the utilization ratio of Ni (OH)2 is raised.``  相似文献   
982.
 用高温应变计和热偶计等诊断技术,研究连续波氧碘化学激光(CW/COIL)与铝合金板作用产生的激光热应力。当照射靶面激光强度约1 000 W/cm2时,激光热应力随靶厚的增加而快速减小。当激光辐照靶材厚度h=1.00 mm、激光强度I=640~980 W/cm2时,激光热应力随辐照靶面激光强度的增加而增大。两者的激光热应力-时间曲线随靶厚的减薄或随辐照靶面激光强度的增加而变得越来越复杂。当靶厚h≤2.50 mm,辐照靶面激光强度I≥800 W/cm2时,激光热应力强度超过激光辐照区材料断裂强度,萌生许多孔洞裂纹,引起材料断裂破坏。  相似文献   
983.
O. Chau  W. Han  M. Sofonea 《Acta Appl Math》2002,71(2):159-178
We consider a mathematical model which describes the frictional contact between a viscoelastic body and a reactive foundation. The process is assumed to be dynamic and the contact is modeled with a general normal damped response condition and a local friction law. We present a variational formulation of the problem and prove the existence and uniqueness of the weak solution, using results on evolution equations with monotone operators and a fixed point argument. We then introduce and study a fully discrete numerical approximation scheme of the variational problem, in terms of the velocity variable. The numerical scheme has a unique solution. We derive error estimates under additional regularity assumptions on the data and the solution.  相似文献   
984.
The modified equivalent inclusion theory by the authors and the internalvariable theory are employed to investigate the evolution of the microcracks in whiskertoughening ceramics and the influence of the microcracks on the mechanical propertiesof the material. The effect of residual thermostrain, whisker content and aspect ratio isconsidered. The modulus, initial nonlinear load, strength and nonlinear constitutiverelation are calculated and some important conclusions are given.  相似文献   
985.
 本文在现有的压扭法和圆片挤压法测试技术的基础上,提出了理论模型更准确、测试更简便、精度更高的纯内滑移法。在纯内滑移法的测试过程中,封垫材料的塑性变形只发生在试样内部,从而排除了压扭法或圆片挤压法中砧子表面摩擦状态对测试结果的影响。本文采用纯内滑移法研究了叶蜡石在不同焙烧温度和吸湿程度下的力学性能,得出了一些有意义的变化规律。  相似文献   
986.
A new titanium-silicate material was synthesized with cubic cage-like tetramethylammonium octasilicate and TiCl4 ethanol solution as precursors. The product was characterized by FTIR, ^29Si NMR, UV-Vis, and XRD. Struc-tural and ingrediental analyses suggest that this material has a layered structure with cubic cage-like polyhedral oligo-silsesquioxane as building blocks and titanium as bridging atoms.[第一段]  相似文献   
987.
Confined layered structures in layer-parallel compression exhibit kink band deformation that has an associated severe initial instability. However, once the first kink band forms the system restabilizes and the bands then propagate in two mechanisms: band broadening and band progression. Previous work on triggering the initial instability and band broadening is now extended to include band progression. A new model for this propagation mechanism that successfully accounts for the modulating restabilizing response is presented and quantitative comparisons with the physical experiments yield excellent results.  相似文献   
988.
The proton induced X-ray emission (PIXE) is used to determine the chemical ingredients of seven main elements in the samples of Ru Guan porcelain glazes and Ru Civil porcelain from Qingliangsi kiln in Baofeng County and the samples of celadon glaze from Zhanggongxiang kiln in Ruzhou City. The PIXE data are then analyzed by scatter analysis and fuzzy cluster method for determining their classification and provenance. The results show that there are obvious differences between the ingredients of glaze material of Ru Guan porcelain and Ru Civil porcelain from Qingliangsi kiln, of which the former ingredients are stable and its source is localized, and that the sources and ingredients of the glaze of Ru Guan porcelain and those of celadon glaze from Zhanggongxiang kiln are not wholly the same, of which the latter sources are much scattering.  相似文献   
989.
Vitamin B12-hyperbranched polymer was synthesized and characterized by UV-vis and NMR spectroscopy as well as DLS. The shape of hybrid polymer was also directly observed by TEM. Microenvironmental polarity around vitamin B12 derivative on the polymer was evaluated by UV-vis absorption peak with α-band of vitamin B12 chromophore.  相似文献   
990.
Small particle size multiphase Li-alloy anodes for lithium-ionbatteries   总被引:2,自引:0,他引:2  
An impressive improvement of the cycling performance of Li-alloy anodes (M + Li+ +e LixM) in rechargeable organic electrolyte lithium batteries can be achieved by replacing compact or large particle size metallic host matrices M (e.g. Sn or Sb) with small particle size (micro- or nano-scale) multiphase metallic host materials like Sn/SnSbn or Sn/SnAgn. Electrochemical alloy deposition is a convenient way to prepare sub-micrometer particles of Sn and SnSbn or Sn and SnAgn. During the first lithium insertion these small particle size multiphase matrix materials are expanded to a porous material, however, without formation of major cracks. This seems not only to be related with the small absolute changes in the size of the individual particles, but also with the fact that the more reactive particles are allowed to expand in a soft and ductile surrounding of still unreacted material.  相似文献   
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