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331.
Improving the evaluation sensitivity of an ultrasonic pulse echo technique using a neural network classifier 总被引:1,自引:0,他引:1
M. Thavasimuthu C. Rajagopalan P. Kalyanasundaram Baldev Raj 《NDT & E International》1996,29(3):175-179
In this paper, the use of an artificial neural network (ANN) for classifying weak ultrasonic signals has been attempted. The limitations of using a single conventional parameter for signal detection and classification (namely peak amplitude alone) are highlighted. Use of a multi-parameter approach is suggested. The ANN used is a multi-layered, feedforward, error- backpropagation network. Results are compared with those of conventional approaches. 相似文献
332.
333.
The use of electricity in buildings constitutes around 16% of Singapore's energy demand. In view of the fact that Singapore is an urban city with no rural base, which depends heavily on air-conditioning to cool its buildings all year round, the survival as a nation depends on its ability to excel economically. To incorporate energy efficiency measures is one of the key missions to ensure that the economy is sustainable. The recently launched building energy efficiency labelling programme is such an initiative. Buildings whose energy performance are among the nation's top 25% and maintain a healthy and productive indoor environment as well as uphold a minimum performance for different systems can qualify to attain the Energy Smart Office Label. Detailed methodologies of the labelling process as well as the performance standards are elaborated. The main strengths of this system namely a rigorous benchmarking database and an independent audit conducted by a private accredited Energy Service Company (ESCO) are highlighted. A few buildings were awarded the Energy Smart Office Label during the launching of the programme conducted in December 2005. The labeling of other types of buildings like hotels, schools, hospitals, etc. is ongoing. 相似文献
334.
335.
James M. Perkins Sarah Fearn Stuart N. Cook Rajagopalan Srinivasan Chris M. Rouleau Hans M. Christen Geoff D. West Richard J. H. Morris Hamish L. Fraser Stephen J. Skinner John A. Kilner David W. McComb 《Advanced functional materials》2010,20(16):2664-2674
Significant recent interest has been directed towards the relationship between interfaces and reports of enhanced ionic conductivity. To gain a greater understanding of the effects of hetero‐interfaces on ionic conductivity, advanced analytical techniques including electron microscopy (TEM/STEM), electron energy loss spectroscopy (EELS), and secondary ion mass spectrometry (SIMS) are used to characterize CeO2/Ce0.85Sm0.15O2 multilayer thin films grown by pulsed laser deposition. High quality growth is observed, but ionic conductivity measured by impedance spectroscopy and 18O tracer experiments is consistent with bulk materials. EELS analysis reveals the unusual situation of layers containing only Ce(IV) adjacent to layers containing both Ce(III) and Ce(IV). Post oxygen annealing induced oxygen diffusion and mixed oxidation states in both layers, but only in the vicinity of low angle grain boundaries perpendicular to the layers. The implications of the anomalous behavior of the Ce oxidation states on the design of novel electrolytes for solid oxide fuel cells is discussed. 相似文献
336.
Jie Li I. A. Karimi Rajagopalan Srinivasan 《American Institute of Chemical Engineers》2010,56(2):441-465
Gasoline is a major contributor to the profit of a refinery. Scheduling gasoline‐blending operations is a critical and complex routine task involving tank allocation, component mixing, blending, product storage, and order delivery. Optimized schedules can maximize profit by avoiding ship demurrage, improving order delivery, minimizing quality give‐aways, avoiding costly transitions and slop generation, and reducing inventory costs. However, the blending recipe and scheduling decisions make this problem a nonconvex mixed‐integer nonlinear program (MINLP). In this article, we develop a slot‐based MILP formulation for an integrated treatment of recipe, specifications, blending, and storage and incorporate many real‐life features such as multipurpose product tanks, parallel nonidentical blenders, minimum run lengths, changeovers, piecewise constant profiles for blend component qualities and feed rates, etc. To ensure constant blending rates during a run, we develop a novel and efficient procedure that solves successive MILPs instead of a nonconvex MINLP. We use 14 examples with varying sizes and features to illustrate the superiority and effectiveness of our formulation and solution approach. The results show that our solution approach is superior to commercial solvers (BARON and DICOPT). © 2009 American Institute of Chemical Engineers AIChE J, 2010 相似文献
337.
P. Victor R. Ranjith A. K. Tyagi S. Rajagopalan S. B. Krupanidhi 《Integrated ferroelectrics》2013,141(1):747-754
Ba1 ? xCaxTiO3 targets were prepared by conventional solid state reaction with varied amounts of the calcium content (5 at.%, 10 at.%) and the thin films were deposited on Pt(111) coated Si substrate using pulsed laser ablation technique. The thin films were deposited at different pressures and temperatures, so as to determine the optimized growth parameter for the good quality BCT thin films. The pressure variation on the growth parameters made a dramatic impact in tailoring the dielectric constant and phase transition. The phase evolution of the BCT thin films evolves from 450°C and at higher substrate temperatures (~700°C) for different partial pressures of oxygen, the preferred orientation of the thin films were observed. The SIMS analysis reveals a sharp interface exist at the bottom electrode (Pt)–BCT thin films indicating no interdiffusion taking place which might lead to the degradation of devices. The BCT thin films deposited at higher pressures (>60 mtorr) exhibited higher Ba content indicating the possibility of the Ca occupying the Ti site and is reflected in the decrease of the dielectric phase transition temperature. The ferroelectric hysteresis and Capacitance voltage measurement shows the signature of ferroelectricity. 相似文献
338.
This paper presents a comprehensive state-of-the-art of the recent advances in simulation of power electronic converter systems.
Knowing the importance of simulation, this paper reviews the various methods of modelling, circuit analysis approaches, numerical
techniques etc. Several general purpose simulators and dedicated power electronic simulators have been discussed. A few demonstrative
examples of simulation of power electronic converters by using different simulators are provided. Practical difficulties in
simulation, challenges, new developments and scope for future work are also discussed. 相似文献
339.
Passlack M. Droopad R. Rajagopalan K. Abrokwah J. Gregory R. Nguyen D. 《Electron Device Letters, IEEE》2005,26(10):713-715
High-/spl kappa/ NMOSFET structures designed for enhancement mode operation have been fabricated with mobilities exceeding 6000 cm/sup 2//Vs. The NMOSFET structures which have been grown by molecular beam epitaxy on 3-in semi-insulating GaAs substrate comprise a 10 nm strained InGaAs channel layer and a high-/spl kappa/ dielectric layer (/spl kappa//spl cong/20). Electron mobilities of >6000 and 3822 cm/sup 2//Vs have been measured for sheet carrier concentrations n/sub s/ of 2-3/spl times/10/sup 12/ and /spl cong/5.85/spl times/10/sup 12/ cm/sup -2/, respectively. Sheet resistivities as low as 280 /spl Omega//sq. have been obtained. 相似文献
340.