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101.
Statistical Learning for Humanoid Robots 总被引:7,自引:0,他引:7
Sethu Vijayakumar Aaron D'souza Tomohiro Shibata Jörg Conradt Stefan Schaal 《Autonomous Robots》2002,12(1):55-69
The complexity of the kinematic and dynamic structure of humanoid robots make conventional analytical approaches to control increasingly unsuitable for such systems. Learning techniques offer a possible way to aid controller design if insufficient analytical knowledge is available, and learning approaches seem mandatory when humanoid systems are supposed to become completely autonomous. While recent research in neural networks and statistical learning has focused mostly on learning from finite data sets without stringent constraints on computational efficiency, learning for humanoid robots requires a different setting, characterized by the need for real-time learning performance from an essentially infinite stream of incrementally arriving data. This paper demonstrates how even high-dimensional learning problems of this kind can successfully be dealt with by techniques from nonparametric regression and locally weighted learning. As an example, we describe the application of one of the most advanced of such algorithms, Locally Weighted Projection Regression (LWPR), to the on-line learning of three problems in humanoid motor control: the learning of inverse dynamics models for model-based control, the learning of inverse kinematics of redundant manipulators, and the learning of oculomotor reflexes. All these examples demonstrate fast, i.e., within seconds or minutes, learning convergence with highly accurate final peformance. We conclude that real-time learning for complex motor system like humanoid robots is possible with appropriately tailored algorithms, such that increasingly autonomous robots with massive learning abilities should be achievable in the near future. 相似文献
102.
高折射率镜头推动浸没式光刻跨越32纳米 总被引:1,自引:0,他引:1
Aaron Hand 《集成电路应用》2006,(6):15-15
在今年的SPIE Microlithography年会上,与会的专家们一如既往地针对如何延伸光学光刻技术使用寿命的问题进行了大量的研讨。而与往年会议不同的是,尽管有人心存疑虑,但今年的会议仍然对双重曝光技术打开了友善之门。关于这项技术,普遍的问题是如何妥善地解决图形套 相似文献
103.
Pipes consisting of coatings 700 μm thick of chemically vapor-deposited TiB2 on carbon were produced and tested for corrosion and/or erosion resistance in a laboratory aluminum smelting cell for 100 h. The projected lifetime of the coating was approximately 30 days, a factor of 50 shorter than that projected by assuming uniform saturation dissolution of TiB2 in molten aluminum. The corrosion and/or erosion as measured from scanning electron micrographs pointed to grain boundary attack with subsequent crystalline pull-out as the mechanism for the shorter than expected lifetimes. 相似文献
104.
The present experiment examined the effects of dopamine receptor antagonism on subjects' motivation to seek food. Rats were trained to discriminate between 2 olfactory cues predicting either the presence (S+) or absence (S–) of food reinforcement in the goal box of a straight-arm runway. Rats learned to traverse the alley quickly when presented with the S+ and much more slowly when presented with the S–. Haloperidol pretreatment was unable to alter this pattern of behavior (i.e., rats still ran quickly when presented with the scent that predicted food availability). Thus, it seems that the same dopamine antagonist treatments that have been shown to disrupt food reinforcement do not prevent the food-seeking behavior produced by presentation of food-predictive cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
105.
106.
First- and second-order information in natural images: a filter-based approach to image statistics 总被引:2,自引:0,他引:2
Johnson AP Baker CL 《Journal of the Optical Society of America. A, Optics, image science, and vision》2004,21(6):913-925
Previous analyses of natural image statistics have dealt mainly with their Fourier power spectra. Here we explore image statistics by examining responses to biologically motivated filters that are spatially localized and respond to first-order (luminance-defined) and second-order (contrast- or texture-defined) characteristics. We compare the distribution of natural image responses across filter parameters for first- and second-order information. We find that second-order information in natural scenes shows the same self-similarity previously described for first-order information but has substantially less orientational anisotropy. The magnitudes of the two kinds of information, as well as their mutual unsigned correlation, are much stronger for particular combinations of filter parameters in natural images but not in unstructured fractal images having the same power spectra. 相似文献
107.
Goldman ER Clapp AR Anderson GP Uyeda HT Mauro JM Medintz IL Mattoussi H 《Analytical chemistry》2004,76(3):684-688
Quantum dots (QDs) have the potential to simplify the performance of multiplexed analysis. In this work, we prepared bioinorganic conjugates made with highly luminescent semiconductor nanocrystals (CdSe-ZnS core-shell QDs) and antibodies to perform multiplexed fluoroimmunoassays. Sandwich immunoassays for the detection of cholera toxin, ricin, shiga-like toxin 1, and staphylococcal enterotoxin B were performed simultaneously in single wells of a microtiter plate. Initially the assay performance for the detection of each toxin was examined. We then demonstrated the simultaneous detection of the four toxins from a single sample probed with a mixture of all four QD-antibody reagents. Using a simple linear equation-based algorithm, it was possible to deconvolute the signal from mixed toxin samples, which allowed quantitation of all four toxins simultaneously. 相似文献
108.
A methodology is described for phase restoration of an object function from differential interference contrast (DIC) images. The methodology involves collecting a set of DIC images in the same plane with different bias retardation between the two illuminating light components produced by a Wollaston prism. These images, together with one conventional bright-field image, allows for reduction of the phase deconvolution restoration problem from a highly complex nonlinear mathematical formulation to a set of linear equations that can be applied to resolve the phase for images with a relatively large number of pixels. Additionally, under certain conditions, an on-line atomic force imaging system that does not interfere with the standard DIC illumination modes resolves uncertainties in large topographical variations that generally lead to a basic problem in DIC imaging, i.e., phase unwrapping. Furthermore, the availability of confocal detection allows for a three-dimensional reconstruction with high accuracy of the refractive-index measurement of the object that is to be imaged. This has been applied to reconstruction of the refractive index of an arrayed waveguide in a region in which a defect in the sample is present. The results of this paper highlight the synergism of far-field microscopies integrated with scanned probe microscopies and restoration algorithms for phase reconstruction. 相似文献
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