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This paper proposes a new LDMOSFET structure with a trenched sinker for high‐power RF amplifiers. Using a low‐temperature, deep‐trench technology, we succeeded in drastically shrinking the sinker area to one‐third the size of the conventional diffusion‐type structure. The RF performance of the proposed device with a channel width of 5 mm showed a small signal gain of 16.5 dB and a maximum peak power of 32 dBm with a power‐added efficiency of 25% at 2 GHz. Furthermore, the trench sinker, which was applied to the guard ring to suppress coupling between inductors, showed an excellent blocking performance below ?40 dB at a frequency of up to 20 GHz. These results confirm that the proposed trenched sinker should be an effective technology both as a compact sinker for RF power devices and as a guard ring against coupling. 相似文献
24.
Sang-Hoon Lee Dae Hwan Kim Kyung Rok Kim Jong Duk Lee Byung-Gook Park Young-Jin Gu Gi-Young Yang Jeong-Taek Kong 《Nanotechnology, IEEE Transactions on》2002,1(4):226-232
A practical model for a single-electron transistor (SET) was developed based on the physical phenomena in realistic Si SETs, and implemented into a conventional circuit simulator. In the proposed model, the SET current calculated by the analytic model is combined with the parasitic MOSFET characteristics, which have been observed in many recently reported SETs formed on Si nanostructures. The SPICE simulation results were compared with the measured characteristics of the Si SETs. In terms of the bias, temperature, and size dependence of the realistic SET characteristics, an extensive comparison leads to good agreement within a reasonable level of accuracy. This result is noticeable in that a single set of model parameters was used, while considering divergent physical phenomena such as the parasitic MOSFET, the Coulomb oscillation phase shift, and the tunneling resistance modulated by the gate bias. When compared to the measured data, the accuracy of the voltage transfer characteristics of a single-electron inverter obtained from the SPICE simulation was within 15%. This new SPICE model can be applied to estimating the realistic performance of a CMOS/SET hybrid circuit or various SET logic architectures. 相似文献
25.
An efficient way to implement the surface impedance boundary conditions (SIBC) for the finite-difference time-domain (FDTD) method is presented in this paper. Surface impedance boundary conditions are first formulated for a lossy dielectric half-space in the frequency domain. The impedance function of a lossy medium is approximated with a series of first-order rational functions. Then, the resulting time-domain convolution integrals are computed using recursive formulas which are obtained by assuming that the fields are piecewise linear in time. Thus, the recursive formulas derived here are second-order accurate. Unlike a previously published method [7] which requires preprocessing to compute the exponential approximation prior to the FDTD simulation, the preprocessing time is eliminated by performing a rational approximation on the normalized frequency-domain impedance. This approximation is independent of material properties, and the results are tabulated for reference. The implementation of the SIBC for a PEC-backed lossy dielectric shell is also introduced 相似文献
26.
Yoon-Ha Jeong Seong-Kue Jo Bong-Hoon Lee Sugano T. 《Electron Device Letters, IEEE》1995,16(3):109-111
High performance enhancement mode InP MISFET's have been successfully fabricated by using the sulfide passivation for lower interface states and with photo-CVD grown P3N5 film used as gate insulator. The MISFET's thus fabricated exhibited exhibited pinch-off behavior with essentially no hysteresis. Furthermore the device showed a superior stability of drain current. Specifically under the gate bias of 2 V for 104 seconds the room temperature drain current was shown to reduce from the initial value merely by 2.9% at the drain voltage of 4 V. The effective electron mobility and extrinsic transconductance are found to be about 2300 cm 2/V·s and 2.7 mS/mm, respectively. The capacitance-voltage characteristics of the sulfide passivated InP MIS diodes show little hysteresis and the minimum density of interface trap states as low as 2.6×1014/cm2 eV has been attained 相似文献
27.
GaN buffer and main layers were grown by the conventional hydride vapor phase epitaxy technique using GaCl3 consecutively. The deposited buffer layers were investigated by atomic force microscopy and X-ray analysis. To examine the behavior of the buffer layers at main layer growth temperature, heat treatment was conducted at 900°C. Based on the results of the buffer layer study, GaN thick films were grown at 1050°C. Optimum deposition conditions of buffer layer from the buffer and main layer studies generally coincided. On the φ scanning pattern, the GaN films grown on (0001) Al2 O3 were single-crystalline. Band-edge emission dominated photoluminescence was observed at room temperature. 相似文献
28.
In this paper, the detectivity is calculated and analyzed with the front-or backside illuminated case for both N-GaSb/p2-Ga0.8In0.2As0.19Sb0.81/p1-Ga0.9In0.1As0.09Sb0.91 and N1-GaSb/n2-Ga0.9In0.1As0.09Sb0.91/p-Ga0.8In0.2As0.19Sb0.81 infrared photovoltaic detectors, respectively. The analysis results show that the main absorption appears in the p-type Ga0.8In0.2As0.19Sb0.81 material with either front- or backside illuminated case for above two structures. In each structure, the carrier concentration obviously affects the detectivity. The carrier concentration in the wide-bandgap material for the isotype heterojunction should be reduced as low as possible to reduce the tunneling rate at the isotype heterointerface. Moreover, the change of the detectivity with the p-side surface recombination velocity for the N1-n2-p structure is more sensitive than that with the p1-side surface recombination velocity for the N-p2-p1 structure. In the N-p2-p1 structure with the incident light from the p1-side surface, two-color detection is achieved. 相似文献
29.
On the influence of N on residual microstrain in cryomilled Ni 总被引:1,自引:0,他引:1
Kyung H. Chung Entrique J. Lavernia 《Metallurgical and Materials Transactions A》2002,33(12):3795-3801
The factors that influence the development of residual microstrain during milling in a liquid nitrogen atmosphere, defined
hereafter as cryomilling, are investigated. The residual microstrains in cryomilled Ni, processed under various cryomilling
conditions, were examined by X-ray diffraction (XRD) and analyzed through the single line approximation (SLA) method. The
average residual microstrains are determined to be in the range of 2×10−3 to 6×10−3. The residual microstrain on the (200) plane is higher than those on the other planes by 33 pct. The residual microstrain
and its anisotropy in Ni are reduced after heat treatment at 800 °C for 1 hour. The measured microstrain is proposed to evolve
from the presence of N and O as impurity atoms in the Ni lattice. Both N and O are introduced from the environment and then
their solubility in Ni is enriched via the generation of defects that occurs during cryomilling. The stable site for N and O atoms in Ni is the octahedral site,
and the sizes of N and O atoms exceed those of the octahedral site of Ni by 48 and 16 pct respectively. Accordingly, a lattice
strain field is expected around interstitial N atoms that are located at octahedral sites. By comparing the crystal structure
around the octahedral site, the stable site for impurity N atoms, in the Ni lattice with that of Ni3N structure, the lattice strains are estimated to be in the range of 5 to 15 pct. The result shows that the (200) plane has
strains that are 2 times higher than those in other planes, and this is argued to be the reason for the measured anisotropy
of residual strain in Ni after cryomilling. 相似文献
30.
The flow and fracture behavior of Be-Al alloys were determined in tension with different levels of superimposed pressure.
The Be-Al alloys were prepared by Brush Wellman, Inc. (Cleveland, OH) from prealloyed powders processed to either a hot isostatically
pressed (“hipped”) or cold isostatically pressed and extruded condition. Significant effects of pressure on both the flow
and ductility have been observed at room temperature, with implications on the formability of these materials. The effects
of changes in processing conditions and stress state on the flow and fracture behavior are summarized in addition to both
optical and scanning electron microscopy (SEM) examination of the fracture surfaces. Separate other studies on the alloy constituents
(e.g., Al and Be) are also reported. The results are also compared to previous works on monolithic materials and composites tested
with high pressure. 相似文献