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81.
Di Bartolomeo A Giubileo F Santandrea S Romeo F Citro R Schroeder T Lupina G 《Nanotechnology》2011,22(27):275702
We discuss the origin of an additional dip other than the charge neutrality point observed in the transfer characteristics of graphene-based field-effect transistors with a Si/SiO2 substrate used as the back-gate. The double dip is proved to arise from charge transfer between the graphene and the metal electrodes, while charge storage at the graphene/SiO2 interface can make it more evident. Considering a different Fermi energy from the neutrality point along the channel and partial charge pinning at the contacts, we propose a model which explains all the features observed in the gate voltage loops. We finally show that the double dip enhanced hysteresis in the transfer characteristics can be exploited to realize graphene-based memory devices. 相似文献
82.
We present the application of the shape-from-silhouette technique to reconstruct the three-dimensional profile of ancient handworks from their x-ray absorption images. The acquisition technique is similar to tomography, since the images are taken all around the object while it is rotated. Some reference points are placed on a small and light structure corotating with the object, and are acquired on the images for calibration and registration. The reconstruction algorithm gives finally the three-dimensional appearance of the handwork. We present the analysis of a bronze pendant of VI-VII century B.C. (Venetic area, Italy) completely hidden by corrosion products. The three-dimensional reconstruction shows that the pendant is a very elaborated piece, with two embraced figures that were completely invisible at the excavation. 相似文献
83.
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85.
Cappiello A Famiglini G Fiorucci C Mangani F Palma P Siviero A 《Analytical chemistry》2003,75(5):1173-1179
A new, simple device generates accurate nano- and microflow rate gradients from any conventional HPLC system. The core of the new device is represented by an electric-actuated, computer-controlled, multiposition HPLC valve. The valve hosts six reservoirs for as many different mobile-phase compositions of increasing strength. A low flow rate stream pushes the weakest solvent through the column as long as required and at the desired flow rate, until the chromatographic run is started. From this time on, the electric actuation allows one to select which reservoir will be on-line with the column and for how long, thus generating a specific solvent gradient, through a sequence of controlled segments of precise mobile-phase composition. This permits one not only to exactly reproduce the programmed slope but also to achieve different gradient shapes (i.e., linear, convex, concave) for different separation needs. The new device has proven to be reliable and reproducible even at the lowest flow rate tested (250 nL x min(-1)) and in different chromatographic conditions. 相似文献
86.
Giorgia Sparapassi Stefano M.Cavaletto Jonathan Tollerud Angela Montanaro Filippo Glerean Alexandre Marciniak Fancesca Giusti Shaul Mukamel Daniele Fausti 《光:科学与应用(英文版)》2022,(3):357-364
We present a novel approach to transient Raman spectroscopy, which combines stochastic probe pulses and a covariance-based detection to measure stimulated Raman... 相似文献
87.
Optimal ensemble construction via meta-evolutionary ensembles 总被引:1,自引:0,他引:1
In this paper, we propose a meta-evolutionary approach to improve on the performance of individual classifiers. In the proposed system, individual classifiers evolve, competing to correctly classify test points, and are given extra rewards for getting difficult points right. Ensembles consisting of multiple classifiers also compete for member classifiers, and are rewarded based on their predictive performance. In this way we aim to build small-sized optimal ensembles rather than form large-sized ensembles of individually-optimized classifiers. Experimental results on 15 data sets suggest that our algorithms can generate ensembles that are more effective than single classifiers and traditional ensemble methods. 相似文献
88.
89.
Filippo Lanubile 《Empirical Software Engineering》1997,2(2):97-108
Technology evaluation is part of the decision-making process of any software organization. Unlike conventional wisdom, empirical
evaluation strives to avoid biased conclusions by relying on observation and looking for pitfalls in the evaluation process.
In this paper, we provide a summary of the maintenance studies presented in the session ‘Study and assessment of (new) technologies’
of the International Workshop on Empirical Studies of Software Maintenance (WESS '96), and also report on the working group
discussion which focused on common problems and open issues in the field of technology evaluation. These empirical studies
are then classified according to a multi-dimensional framework to synthesize the state of the research in technology evaluation
and ultimately discover interesting patterns.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
90.
This article presents the system WHY, which learns and updates a diagnostic knowledge base using domain knowledge and a set of examples. The a priori knowledge consists of a causal model of the domain that states the relationships among basic phenomena, and a body of phenomenological theory that describes the links between abstract concepts and their possible manifestations in the world. The phenomenological knowledge is used deductively, the causal model is used abductively, and the examples are used inductively. The problems of imperfection and intractability of the theory are handled by allowing the system to make assumptions during its reasoning. In this way, robust knowledge can be learned with limited complexity and a small number of examples. The system works in a first-order logic environment and has been applied in a real domain. 相似文献