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101.
双带式薄板坯连铸过程应用了长直武、全移动型结晶器。这两个主结晶表面由两条翱紧的薄盎属带准确地变撑,并且用高速冷却水冷却,以恒定速度传动。这两条基本平行的金属带之间的空同在边缘处由金属边缘挡块组成的连续封闭环封闭,封闭环与金属带同步运行。 相似文献
102.
103.
Haglmüller J Rauter H Bauer G Pittner F Schalkhammer T 《IEE proceedings. Nanobiotechnology》2005,152(2):53-63
The resonance-enhanced absorption (REA) by metal clusters on a surface is an effective technique on which to base bio-optical devices. A four-layer device consisting of a metal mirror, a polymer or glass-type distance layer, a biomolecule interaction layer and a sub-monolayer of biorecognitively bound metal nano-clusters is reported. Experiments indicate a strong influence of the resonator homogeneity on the absorption maximum. Layer stability plays an important role in the overall performance of the device. Techniques and optimised lab protocols to set up biochips that use the REA process in the detection are presented. The sensors show one to three narrow reflection minima in the visible and or infra-red (IR) part of the spectrum and therefore they do not suffer from the spectral limitations associated with spherical gold colloids. Metal clusters (synthesised by thermal step reduction) as well as metal- dielectric shell clusters (synthesised by various shell deposition processes) are used to precisely shift the readout of the device to any frequency in the visible and near IR range. Disposable single-step protein chips, DNA assays as well as complex biochip arrays are established that use various DNARNA, antigen-antibody and protein-protein interaction systems. 相似文献
104.
Han F Wang Y Sims CE Bachman M Chang R Li GP Allbritton NL 《Analytical chemistry》2003,75(15):3688-3696
In the past decade, capillary electrophoresis has demonstrated increasing utility for the quantitative analysis of single cells. New applications for the analysis of dynamic cellular properties demand sampling methods with sufficient temporal resolution to accurately measure these processes. In particular, intracellular signaling pathways involving many enzymes can be modulated on subsecond time scales. We have developed a technique to rapidly lyse an adherent mammalian cell using a single electrical pulse followed by efficient loading of the cellular contents into a capillary. Microfabricated electrodes were designed to create a maximum voltage drop across the flattened cell's plasma membrane at a minimum interelectrode voltage. The influence of the interelectrode distance, pulse duration, and pulse strength on the rate of cell lysis was determined. The ability to rapidly lyse a cell and collect and separate the cellular contents was demonstrated by loading cells with Oregon Green and two isomers of carboxyfluorescein. All three fluorophores were detected with a separation efficiency comparable to that of standards. Parallel comparison of electrical lysis to that produced by a laser-based lysis system revealed that the sampling efficiencies of the two techniques were comparable. Rapid cell lysis by an electrical pulse may increase the application of capillary electrophoresis to the study of cellular dynamics requiring fast sampling times. 相似文献
105.
The optical properties of copper Cu-Ni compound metal island (CMI) films composed of nanoclusters of an alloy of Cu and Ni have been experimentally investigated. The spectral characteristics of the Cu-Ni CMI films are intermediate between those of conventional Cu and Ni island films in visible and near-IR regions. In addition, the magneto-optic effect has been observed in the Cu-Ni CMI films. It is also shown that the Faraday rotation in the Cu-Ni CMI films can easily be controlled by selection of the mixture ratio of Cu and Ni. 相似文献
106.
A novel mesoporous TiO2 phosphor doped with Eu was synthesized through a facile hydrothermal synthesis method using cetyltrimethylammonium bromide as structure template reagent. The samples were characterized by X-ray diffraction, N2 adsorption-desorption, scanning electron microscope, high-resolution transmission electron microscopy, ultraviolet visible diffuse reflectance, X-ray photoelectron spectroscopy, and three dimensional Photoluminescence. The X-ray diffraction results demonstrated that the products were anatase type with polycrystalline. N2 adsorption-desorption analysis showed that the samples were of high ordered double mesoporous structures. Eu-doped mesoporous TiO2 indicated the typical fluorescent spectra of Eu3+ ion occurred: the excited-states at 5L6 (394 nm), 5D2 (465 nm) and 5D1 (535 nm); the main emission peaks at 592 and 617 nm, corresponding with the transitions 5D0 --> 7F1 and 5D0 --> 7F2, respectively. Meanwhile, the phenomena of Eu(3+)-doped mesoporous TiO2 phosphor with efficient nonradiative energy transfer from the mesoporous TiO2 host to the activator Eu3+ ions was observed and possible emission mechanism was proposed. High dispersion of Eu in mesoporous TiO2 matrix was responsible for enhanced luminescence. 相似文献
107.
Weiss JD Tarantini C Jiang J Kametani F Polyanskii AA Larbalestier DC Hellstrom EE 《Nature materials》2012,11(8):682-685
The K- and Co-doped BaFe(2)As(2) (Ba-122) superconducting compounds are potentially useful for applications because they have upper critical fields (H(c2)) of well over 50?T, H(c2) anisotropy γ < 2and thin-film critical current densities J(c) exceeding 1?MA?cm(-2) (refs 1-4) at 4.2?K. However, thin-film bicrystals of Co-doped Ba-122 clearly exhibit weak link behaviour for [001] tilt misorientations of more than about 5°, suggesting that textured substrates would be needed for applications, as in the cuprates. Here we present a contrary and very much more positive result in which untextured polycrystalline (Ba(0.6)K(0.4))Fe(2)As(2) bulks and round wires with high grain boundary density have transport critical current densities well over 0.1?MA?cm(-2) (self-field, 4.2?K), more than 10 times higher than that of any other round untextured ferropnictide wire and 4-5 times higher than the best textured flat wire. The enhanced grain connectivity is ascribed to their much improved phase purity and to the enhanced vortex stiffness of this low-anisotropy compound (γ~1-2) when compared with YBa(2)Cu(3)O(7-x) (γ~5). 相似文献
108.
109.
Eppstein MJ Fedele F Laible J Zhang C Godavarty A Sevick-Muraca EM 《IEEE transactions on medical imaging》2003,22(10):1215-1223
Many approaches to fluorescence tomography utilize some form of regularized nonlinear least-squares algorithm for data inversion, thus requiring repeated computation of the Jacobian sensitivity matrix relating changes in observable quantities, such as emission fluence, to changes in underlying optical parameters, such as fluorescence absorption. An exact adjoint formulation of these sensitivities comprises three terms, reflecting the individual contributions of 1) sensitivities of diffusion and decay coefficients at the emission wavelength, 2) sensitivities of diffusion and decay coefficients at the excitation wavelength, and 3) sensitivity of the emission source term. Simplifying linearity assumptions are computationally attractive in that they cause the first and second terms to drop out of the formulation. The relative importance of the three terms is thus explored in order to determine the extent to which these approximations introduce error. Computational experiments show that, while the third term of the sensitivity matrix has the largest magnitude, the second term becomes increasingly significant as target fluorophore concentration or volume increases. Image reconstructions from experimental data confirm that neglecting the second term results in overestimation of sensitivities and consequently overestimation of the value and volume of the fluorescent target, whereas contributions of the first term are so low that they are probably not worth the additional computational costs. 相似文献
110.
F.J. Liu M.C. Zhang J.X. Dong Y. W. Zhang 《金属学报(英文版)》2007,20(2):102-110
High temperature oxidation behaviors of FGH96 P/M superalloy have been studied in air at temperatures ranging from 600 to 1000℃. By means of isothermal oxidation testing,X-ray diffraction,SEM(scanning electron microscopy),and EDS(energy dispersive X-ray spectroscopy) analyses,the oxidation kinetics as well as the composition and morphology of scales were investigated. Thermodynamic calculations were used to explain the oxidation mechanism. The results showed that as the oxidation temperature increased,the oxidation rate,the scale thickness,and scale spallation increased. FGH96 P/M superalloy exhibits good oxidation resistance at temperature below 800℃. The oxidation kinetics follows an approximately parabolic rate law,and the oxide layer was mainly composed of Cr2O3,TiO2,and a little amount of NiCr2O4. The oxidation is controlled by the transmission of chromium,titanium,and oxygen through the oxide scale. 相似文献