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101.
The field-oriented control, or the vector control, has emerged as a powerful tool for controlling squirrel-cage induction motors. The dynamic performance, however, depends on the controllability of the stator currents. 相似文献
102.
Gouardes E. Miyamoto T. Kawaguchi M. Kondo K. Koyama F. Iga K. 《Photonics Technology Letters, IEEE》2002,14(7):896-898
Proposes two new structures, the GaInAs-GaInNAs intermediate layer (IML) and the GaInNxAs graded wells, which show better optical properties than the commonly used GaInNAs-GaAs rectangular quantum-wells. A 1240-nm emitting IML laser has been achieved with a low-threshold current density (200 A/cm2/well) and a relatively high characteristic temperature (To=100 K). The IML structure is very promising for long wavelength GaAs-based laser applications 相似文献
103.
Norimasa Nukaga Hirofumi Ono Takuya Shida Hideaki Machida Toshie Suzuki Hiroshi Funakubo 《组合铁电体》2013,141(1):215-222
SrBi 2 Ta 2 O 9 thin films were prepared by ECR plasma enhanced metalorganic chemical vapor deposition (ECR-MOCVD) with a liquid-delivery system using one cocktail source without an additional solvent. The strontium-tantalum double alkoxide, Sr{Ta[OC 2 H 4 H(CH 3 ) 2 ](OC 2 H 5 ) 5 } 2 , was dissolved in stabilized trimethyl bismuth, Bi(CH 3 ) 3 / dioxane. This source system has been used in a conventional bubbling system. Deposition rate and the composition of the films were strictly controlled by the concentration and the composition of the cocktail source. Therefore, high reproducibility was realized by using this system. The constituent phase of the stoichiometric SBT film as-deposited at 500 C on a (111)Pt/TiO 2 /SiO 2 /Si substrate was a fluorite phase and transformed to the single phase of SBT by the post annealing at 800 C. It showed almost the same ferroelectricity as the stoichiometric composition film. 相似文献
104.
Shozo Koyama Yoon Ahm Kim Kenji Takeuchi Naomi Kuroiwa Tamotsu Tsukahara 《Carbon》2009,47(5):1365-503
The longstanding question as to whether carbon nanotubes are intrinsically toxic hinders their widespread industrial application. Here, we clarify the effect of impurities within such tubes through systemic studies of immunological responses in mice by monitoring and examining changes in peripheral T-cell subset and peripheral cytokine levels and histology. Contaminated and clean tubes were subcutaneously implanted in mice. The implanted tubes with impurities clearly induced immunological toxicity and localized alopecia, whereas extremely pure implanted tubes showed good biocompatibility. Our studies suggest that such high-temperature thermal treatment is an effective way to improve the biocompatibility of carbon nanotube. 相似文献
105.
106.
This paper deals with a dynamic voltage restorer (DVR) characterized by installing the shunt converter at the load side. The DVR can compensate for the load voltage when a voltage sag appears in the supply voltage. An existing DVR requires a large capacitor bank or other energy‐storage elements such as double‐layer capacitors or batteries. The DVR presented in this paper requires only a small DC capacitor intended for smoothing the DC‐link voltage. Moreover, three control methods for the series converter are compared and discussed to reduce the series‐converter rating, paying attention to the zero‐sequence voltages included in the supply voltage and the compensating voltage. Experimental results obtained from a 200‐V, 5‐kW laboratory system are shown to verify the viability of the system configuration and the control methods. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(3): 73–82, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20460 相似文献
107.
108.
Takai Y. Fujita M. Nagata K. Isa S. Nakazawa S. Hirobe A. Ohkubo H. Sakao M. Horiba S. Fukase T. Takaishi Y. Matsuo M. Komuro M. Uchida T. Sakoh T. Saino K. Uchiyama S. Takada Y. Sekine J. Nakanishi N. Oikawa T. Igeta M. Tanabe H. Miyamoto H. Hashimoto T. Yamaguchi H. Koyama K. Kobayashi Y. Okuda T. 《Solid-State Circuits, IEEE Journal of》2000,35(2):149-162
This paper describes three circuit technologies indispensable for high-bandwidth multibank DRAM's. (1) A clock generator based on a bidirectional delay (BDD) eliminates the output skew. The BDD measures the cycle time as the quantity charged or discharged of an analog quantity, and replicates it in the next cycle. This achieves a 0.18-mm 2, two-cycle-lock clock generator operating from 25 to 167 MHz with a 30-ps resolution. (2) A quad-coupled receiver eliminates the internal skew caused by the difference between a rise input and a fall input by 40%. (3) An interbank shared redundancy scheme (ISR) with a variable unit redundancy (VUR) efficiently increases yield in multibank DRAM's. The ISR allows redundancy match circuits to be shared with two or more banks. The VUR allows the number of units replaced to be variable. These circuit technologies achieved a 250-Mb/s/pin, 8-bank, 1-Gb double-data-rate synchronous DRAM 相似文献
109.
Kanemasa A. Sugiyama A. Koike S. Koyama T. 《Selected Areas in Communications, IEEE Journal on》1986,4(8):1359-1366
This paper proposes an ISDN subscriber loop transmission system based on an echo cancellation technique which fully supports the CCITT recommended basic interface for ISDN, i.e.,B + B + D over metallic cables. System design considerations of cable loss, crosstalk, impulsive noise, and system requirements such as power feeding on a caLl-by-call basis are discussed, and a transmission system is proposed. The proposed system is characterized by the use of a new line code, named "modified biphase code." The use of this code with fixed line loss equalization and coherent detection achieves circuit simplification. A special adaptation algorithm is incorporated with the echo canceller that significantly reduces convergence time. Experimental results show satisfactory performance with respect to the residual echo and the bit error rate. Since the system requires only a simple nonadaptive circuit for analog portion, it is suitable for LSI implementation. 相似文献
110.
Hirofumi Matsuda Makoto Kuwabara Kohichi Hamamoto 《Journal of the American Ceramic Society》1998,81(1):229-232
Thin, semiconducting BaTiO3 ceramic wires prepared in the present study exhibited reversible stress-induced, nonlinear current—;voltage characteristics across several grain boundaries. A remarkable change in resistance with the application (by the three-point bending method) of only ∼1% tensile deformation indicated that the BaTiO3 wires may have potential as stress-sensing devices. Resistance in the BaTiO3 wires bot increased and decreased with increasing tensile stress parallel to the electric fields, far below the ferroelectric transition temperature, T c ; in Sr-substituted wires near T c , on the other hand, resistance only increased. Detailed studies of the patterns and fluctuation of polarization at grain boundaries could be meaningful, because stress-sensing characteristics may be induced by changes in the relative angle between polarization vectors of adjacent grains. 相似文献