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81.
82.
Agnieszka Miguel Eve Riskin Richard Ladner Dane Barney 《Signal, Image and Video Processing》2012,6(4):597-611
We investigate the ability to derive meaningful information from decompressed imaging spectrometer data. Hyperspectral images are compressed with near-lossless and lossy coding methods. Linear prediction between the bands is used in both cases. Each band is predicted by a previously transmitted band. The residual is formed by subtracting the prediction from the original data and then is compressed either with a near-lossless bit-plane coder or with the lossy JPEG2000 algorithm. We study the effects of these two types of compression on hyperspectral image processing such as mineral and vegetation content classification using whole- and mixed pixel analysis techniques. The results presented in this paper indicate that an efficient lossy coder outperforms near-lossless method in terms of its impact on final hyperspectral data applications. 相似文献
83.
P.-Y. Chan E. Suarez M. Gogna B.I. Miller E.K. Heller J.E. Ayers F.C. Jain 《Journal of Electronic Materials》2012,41(10):2810-2815
This paper presents an indium gallium arsenide (InGaAs) quantum dot gate field-effect transistor (QDG-FET) that exhibits an intermediate “i” state in addition to the conventional ON and OFF states. The QDG-FET utilized a II–VI gate insulator stack consisting of lattice-matched ZnSe/ZnS/ZnMgS/ZnS/ZnSe for its high-κ and wide-bandgap properties. Germanium oxide (GeO x )-cladded germanium quantum dots were self-assembled over the gate insulator stack, and they allow for the three-state behavior of the device. Electrical characteristics of the fabricated device are also presented. 相似文献
84.
Pfiester J.R. Baker F.K. Mele T.C. Tseng H.-H. Tobin P.J. Hayden J.D. Miller J.W. Gunderson C.D. Parrillo L.C. 《Electron Devices, IEEE Transactions on》1990,37(8):1842-1851
The penetration of boron into and through the gate oxides of PMOS devices which employ p+ doped polysilicon gates is studied. Boron penetration results in large positive shifts in V FB , increased PMOS subthreshold slope and electron trapping rate, and decreased low-field mobility and interface trap density. Fluorine-related effects caused by BF2 implantations into the polysilicon gate are shown to result in PMOS threshold voltage instabilities. Inclusion of a phosphorus co-implant or TiSi2 salicide prior to gate implantation is shown to minimize this effect. The boron penetration phenomenon is modeled by a very shallow, fully-depleted p-type layer in the silicon substrate close to the SiO 2/Si interface 相似文献
85.
Liou K.-Y. Koren U. Burrows E.C. Oron M. Miller B.I. Young M. Raybon G. Burrus C.A. 《Photonics Technology Letters, IEEE》1990,2(12):878-880
Monolithic integration of a monitoring detector with an optical amplifier simplifies the use of an amplifier in lightwave systems. The structure and performance are described of a monolithically integrated semiconductor optical amplifier with low-loss Y -branching waveguides and a monitoring p-i-n detector. The photocurrent of the integrated detector can be used as a single control parameter for amplifier output leveling, gain optimization, and in situ monitoring of facet antireflective coatings 相似文献
86.
D. van den Bout P. Franzon J. Paulos T. Miller W. Snyder T. Nagle W. Liu 《Journal of Signal Processing Systems》1990,1(4):367-385
This paper discusses research on scalable VLSI implementations of feed-forward and recurrent neural networks. These two families of networks are useful in a wide variety of important applications—classification tasks for feed-forward nets and optimization problems for recurrent nets—but their differences affect the way they should be built. We find that analog computation with digitally programmable weights works best for feed-forward networks, while stochastic processing takes advantage of the integrative nature of recurrent networks. We have shown early prototypes of these networks which compute at rates of 1–2 billion connections per second. These general-purpose neural building blocks can be coupled with an overall data transmission framework that is electronically reconfigured in a local manner to produce arbitrarily large, fault-tolerant networks. 相似文献
87.
G. P. Watson M. O. Thompson D. G. Ast A. Fischer-Colbrie J. Miller 《Journal of Electronic Materials》1990,19(9):957-965
As shown previously, the misfit dislocation density of strained epitaxial III–V layers can be significantly reduced by isolating
sections (via patterned etching) of a GaAs substrate before epitaxial growth. A disadvantage of this technique is that the
wafer surface is no longer planar, which can complicate subsequent device fabrication. As an alternative, we have investigated
growth of 350 nm of In0.5Ga{0.95}As by molecular beam epitaxy at two temperatures on substrates which were patterned and selectively damaged by Xe
ion implantation (300 keV, 1015 cm2). Selectively etched substrates were prepared as reference samples as well. The propagation of the misfit dislocations was
stopped by the ion-implanted regions of the low growth temperature (400° C) material, but the damaged portions also acted
as copious nucleation sources. The resulting dislocation structure was highly anisotropic, with dislocation lines occurring
in virtually only one direction. At the higher growth temperature (500° C) the defect density fell, but the ion damaged sections
no longer blocked dislocation glide. Images from cathodoluminescence and transmission electron microscopy show thatthe low
growth temperature material has a dislocation density of 70,000 cm-1 in the 110 direction and less than 10,000 cm-1 in the 110 direction. Ion channeling and x-ray diffraction show that strain is relieved in only one direction. The strain
relief is consistent with the relief derived from TEM dislocation counts and Burgers vector determination. However, even this
high dislocation count is not sufficient to reach the expected equilibrium strain. Reasons for the anisotropy are discussed. 相似文献
88.
Jian-zhong Zhang Vazquez J.M. Mazilu M. Miller A. Galbraith I. 《Quantum Electronics, IEEE Journal of》2003,39(11):1388-1393
Using the Foreman effective mass Hamiltonian, the electronic structure of the valence band and the interband dipole matrix elements in In/sub x/Ga/sub 1-x/As-In/sub y/Ga/sub 1-y/As/sub z/P/sub 1-z/ quantum-well optical amplifiers are calculated, taking into account the valence band mixing and the biaxial strain. The optical field of the amplified pulse is calculated by solving the wave equation with the computed polarization as a source term. A novel wavelet transform is introduced in analyzing the pulse chirp imposed by the optical amplifier. In the linear propagation regime, the spectrum of the amplified pulse can be either red-shifted or blue-shifted with respect to its initial center frequency, depending on the local gain dispersion spanned by the pulse spectrum. The output pulse shape can be retarded or advanced, depending on the local gain and group velocity dispersion. Furthermore, an initially unchirped pulse centered in the tail of the gain spectrum is significantly reshaped after propagating 600 /spl mu/m, and its spectrum is broadened and distorted considerably. In the spectral region where both gain and group velocity change rapidly, the frequency chirp for a linearly chirped input pulse is significantly weakened after propagation. 相似文献
89.
90.
We present herein a decoupled multiuser acquisition (DEMA) algorithm for code-timing estimation in asynchronous code-division multiple-access (CDMA) communication systems. The DEMA estimator is an asymptotic (for large data samples) maximum-likelihood method that models the channel parameters as deterministic unknowns. By evoking the mild assumption that the transmitted data bits for all users are independently and identically distributed, we show that the multiuser timing estimation problem that usually requires a search over a multidimensional parameter space decouples into a set of noniterative one-dimensional problems. Hence, the proposed algorithm is computationally efficient. DEMA has the desired property that, in the absence of noise, it obtains the exact parameter estimates even with a finite number of data samples which can be heavily correlated. Another important feature of DEMA is that it exploits the structure of the receiver vectors and, therefore, is near-far resistant. Numerical examples are included to demonstrate and compare the performances of DEMA and a few other standard code-timing estimators 相似文献