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71.
L-Arginine or saline was administered intravenously by rapid infusion into 16 late-pregnant Holstein cows to study changes of prolactin, growth hormone, insulin, total protein, urea nitrogen, and subsequent lactation. Arginine was infused daily at .1 g/kg body weight starting about 7 days prior to predicted calving until calving. Blood was sampled via a jugular cannula at 0700, 0715, 0730 (infusion immediately followed 0730 h sample), 0745, 0815, 0845, 1100, 1300, 1500, 1700, and 1900 h. Arginine infusion evoked dramatic but transient increase of concentrations of blood serum prolactin, growth hormone, and insulin. Urea nitrogen also was elevated in blood serum but not total protein. The secretory response of prolactin, growth hormone, and insulin to daily arginine infusion during the entire prepartum period was not diminished. Milk production for the first 22 wk of lactation tended to be higher (by about 10%) for cows infused with arginine as compared to cows infused with saline. Therefore, repeated arginine infusion in late-pregnant cows dramatically increased prolactin, growth hormone, and insulin and tended to increase subsequent milk yield.  相似文献   
72.
Irradiation of a dielectric material with microwave irradiation results in energy transfer due to rotational-vibrational transitions within the molecule. The energy transfer results in a local rise in temperature within the material. Microwave-induced reactions can occur at a lower average temperature than convective heating resulting in faster thermal curing of polymer dielectrics because the energy absorption is localized at particular sites. In this study, variable frequency microwave (VFM) curing of epoxy-based dielectric films was investigated. The microwave energy was swept through a range of frequencies to dissipate standing waves so that metallic conductors could be present with the dielectric films. The rate of reaction and film properties of polyamideimide (PAI) and bisphenol A epoxy resin (BPAEp) were studied. Benzanilide and BPAEp were used as model compounds for the reaction between the amide and epoxy. Compared to convective heating, the microwave reaction rates were higher at each isothermal cure temperature. The resulting mechanical properties of the films cured by microwave heated were superior to thermally cured materials. The elastic modulus of VFM cured PAI/BPAEp films was less than that of thermally cured films and the elongation to break was twice as high. Further, the adhesion to copper was improved with microwave processing. The chemical structure of the VFM cured polymer was different from the thermally cured polymer, based on Fourier transform infrared analysis, and is likely the origin of the improved properties.  相似文献   
73.
In this paper, we propose a nonparametric Bayesian model combined with the Indian buffet process (IBP) for a finite impulse response (FIR) system. We develop an FIR system identification method that can simultaneously estimate the number of FIR taps and coefficients. In the proposed model, each FIR tap consists of a coefficient and a gain, and the gain is a binary value. An infinite-dimensional binary vector is composed of binary values, and we assume that this binary vector is generated by the IBP. To identify the FIR system, we specify the likelihood function and prior distributions of the parameters and derive their posterior distributions. We can simultaneously estimate the number of FIR taps and coefficients by sampling from posterior distributions using the Gibbs sampler. Our simulations demonstrate that although the number of FIR taps is unknown, the identification performance of the proposed method in a high signal-to-noise ratio environment is similar to or better than that of the conventional least square solution.  相似文献   
74.
In Mott materials strong electron correlation yields a spectrum of complex electronic structures. Recent synthesis advancements open realistic opportunities for harnessing Mott physics to design transformative devices. However, a major bottleneck in realizing such devices remains the lack of control over the electron correlation strength. This stems from the complexity of the electronic structure, which often veils the basic mechanisms underlying the correlation strength. This study presents control of the correlation strength by tuning the degree of orbital overlap using picometer-scale lattice engineering. This study illustrates how bandwidth control and concurrent symmetry breaking can govern the electronic structure of a correlated SrVO3 model system. This study shows how tensile and compressive biaxial strain oppositely affect the SrVO3 in-plane and out-of-plane orbital occupancy, resulting in the partial alleviation of the orbital degeneracy. The spectral weight redistribution under strain is derived and explained, which illustrates how high tensile strain drives the system toward a Mott insulating state. Implementation of such concepts can push correlated electron phenomena closer toward new solid-state devices and circuits. These findings therefore pave the way for understanding and controlling electron correlation in a broad range of functional materials, driving this powerful resource for novel electronics closer toward practical realization.  相似文献   
75.
A radio frequency (RF) telemetry system with a shape memory alloy microelectrode was designed and fabricated. The total size and weight are 15 mm x 8 mm and 0.1 g, respectively. Since the telemeter is small and light enough to be loaded on a small animal such as an insect, the system can be used for the neural recording of a freely moving insect. The RF-telemeter can transmit signals by frequency modulation transmission at 80-90 MHz. The transmitted signals can be received up to about 16 meters away from the telemeter with a high signal-to-noise ratio. The neural activity can be detected without attenuation by using an instrumentation amplifier with its input impedance set to 2 Mohms at 1 kHz. The telemeter was loaded on a cockroach and the neural activity during a free-walk was successfully measured through this telemetry system.  相似文献   
76.
The thermal fatigue properties of Sn-xAg-0.5Cu (x=1, 2, 3, and 4 in mass%) flip-chip interconnects were investigated to study the effect of silver content on thermal fatigue endurance. The solder joints with lower silver context (x=1 and 2) had a greater failure rate compared to those with higher silver content (x=3 and 4) in thermal fatigue testing. Cracks developed in the solders near the solder/chip interface for all joints tested. This crack propagation may be mainly governed by the nature of the solders themselves because the strain-concentrated area was similar for tested alloys independent of the silver content. From the microstructural observation, the fracture was a mixed mode, transgranular and intergranular, independent of the silver content. Higher silver content alloys (x=3 and 4) had finer Sn grains before thermal cycling according to the dispersion of the Ag3Sn intermetallic compound, and even after the cycling, they suppressed microstructural coarsening, which degrades the fatigue resistance. The fatigue endurance of the solder joints was strongly correlated to the silver content, and solder joints with higher silver content had better fatigue resistance.  相似文献   
77.
Fiber Bragg grating (FBG)-based bandpass filters, while possessing close to ideal sharp rolloff characteristics, can suffer from a significant amount of in-band dispersion. Results concerning the compensation of the in-band dispersion of a typical 100-GHz FBG using two thin-film all-pass filters, each composed of two coupled-cavities packaged in a compact configuration, are presented. The total peak insertion loss of the compensation package is less than 2.5 dB.  相似文献   
78.
This paper presents an experimental study on the development of a cyclogyro-based flying robot with a new variable angle of attack mechanism. A cyclogyro is a flying machine supported in the air by power-driven rotors that rotate about a horizontal axis, like the paddle-wheels of a steamboat. Machines of this type have been designed by some companies but there has been no record of any successful flights. Our design starts with a new variable angle of attack mechanism with an eccentric (rotational) point in addition to a rotational point connecting to a motor. The main feature of the mechanism with the eccentric rotational point is the ability to change attack of angles in accordance with the wing positions (as determined by the rotational angles of the cyclogyro) without actuators. The design parameters (wing span, the number of wings, and eccentric distance) of the flying robot are determined through a series of experiments. Experimental results show that the cyclogyro-based flying robot with the new variable angle of attack mechanism is capable of generating sufficient lift force for flying.  相似文献   
79.
A quasi-end-fire (QEF) pumping scheme was proposed and studied as a novel laser-pumping-scheme for a laser-dye-doped plastic waveguide laser with distributed feedback. This pumping scheme resembled longitudinal pumping, but also has the advantage of controllable absorption length of the injected pump beam. A first demonstration of the QEF was performed and the pumping beam controlling was also investigated.  相似文献   
80.
This paper describes how block-coded modulation (BCM) and multiple BCM (MBCM) with Viterbi decoding can be designed for use in Rayleigh fading and severe Rician fading channels. New codes are developed by modifying known codes to increase the minimum symbol distance, which is one of the distances that has a strong effect on the bit error rate (BER) performance under fading channels. Combined with anti-fading techniques such as fading compensation, interleaving, and branch weighting, the new codes significantly improve BER performance. Computer simulations were used to confirm the code performance  相似文献   
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