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961.
本文介绍一个能采集和分析四个512道γ谱的微计算机多道系统,该系统也可作一个2048道的脉冲幅度分析器使用,或用于多样品低本底液闪计数测量和数据处理。这里重点叙述多道部分的系统构成、工作原理、软件功能和性能指标。 相似文献
962.
In this paper a low bit rate subband coding scheme for image sequences is described. Typically, the scheme is based on temporal DPCM in combination with an intraframe subband coder. In contrast to previous work, however, the subbands are divided into blocks onto which conditional replenishment is applied, while a bit allocation algorithm divides the bits among the blocks assigned for replenishment. A solution is given for the ‘dirty window’ effect by setting blocks to zero that were assigned to be replenished but received no bits. The effect of motion compensation and the extension to color images are discussed as well. Finally, several image sequence coding results are given for a bit rate of 300 kbit/s. 相似文献
963.
The topographic organization of brain areas such as theprimary visual cortex is usually assumed to reflect exclusivelyanatomic constraints like wiring length. Here we argue thattopography is in fact imbedded in the statistical structure of thenatural sensory input. Thus, the topography of sensory areasreflects the statistics of its input as well, in the same way as thesparseness of cell outputs. 相似文献
964.
965.
Diversity-and-multiplexing tradeoff and throughput of superposition coding relaying strategy 总被引:1,自引:1,他引:0
While the Network Coding cooperative relaying (NC-relaying) has the merit of high spectral ef-ficiency, Superposition Coding relaying (SC-relaying) has the merit of high throughput. In this paper, a novel concept, coded cooperative relaying, is presented, which is a unified scheme of the NC-relaying and SC-relaying. For the SC-relaying strategy which can be considered one-way coded relaying scheme with multi-access channel, the close-form solution of the outage probabilities of the basic signal and additional signal are obtained firstly. Secondly, the Diversity-and-Multiplexing Tradeoff (DMT) characteristics of ba-sic signal and additional signal are investigated entirely as well as the optimal close-form solutions. The compared numerical analysis shows the evaluation error of throughput based on the close-form solution is about 0.15 nats, which is within the acceptable error range. Due to the mutual effect between the both source signals, the available maximal values of the two multiplexing gains are less than 1. 相似文献
966.
Imposing maximum length scale in topology optimization 总被引:3,自引:3,他引:0
James K. Guest 《Structural and Multidisciplinary Optimization》2009,37(5):463-473
This paper presents a technique for imposing maximum length scale on features in continuum topology optimization. The design
domain is searched and local constraints prevent the formation of features that are larger than the prescribed maximum length
scale. The technique is demonstrated in the context of structural and fluid topology optimization. Specifically, maximum length
scale criterion is applied to (a) the solid phase in minimum compliance design to restrict the size of structural (load-carrying)
members, and (b) the fluid (void) phase in minimum dissipated power problems to limit the size of flow channels. Solutions
are shown to be near 0/1 (void/solid) topologies that satisfy the maximum length scale criterion. When combined with an existing
minimum length scale methodology, the designer gains complete control over member sizes that can influence cost and manufacturability.
Further, results suggest restricting maximum length scale may provide a means for influencing performance characteristics,
such as redundancy in structural design. 相似文献
967.
S.P. Moustakidis Author Vitae Author Vitae 《Pattern recognition》2010,43(11):3712-3729
An efficient filter feature selection (FS) method is proposed in this paper, the SVM-FuzCoC approach, achieving a satisfactory trade-off between classification accuracy and dimensionality reduction. Additionally, the method has reasonably low computational requirements, even in high-dimensional feature spaces. To assess the quality of features, we introduce a local fuzzy evaluation measure with respect to patterns that embraces fuzzy membership degrees of every pattern in their classes. Accordingly, the above measure reveals the adequacy of data coverage provided by each feature. The required membership grades are determined via a novel fuzzy output kernel-based support vector machine, applied on single features. Based on a fuzzy complementary criterion (FuzCoC), the FS procedure iteratively selects features with maximum additional contribution in regard to the information content provided by previously selected features. This search strategy leads to small subsets of powerful and complementary features, alleviating the feature redundancy problem. We also devise different SVM-FuzCoC variants by employing seven other methods to derive fuzzy degrees from SVM outputs, based on probabilistic or fuzzy criteria. Our method is compared with a set of existing FS methods, in terms of performance capability, dimensionality reduction, and computational speed, via a comprehensive experimental setup, including synthetic and real-world datasets. 相似文献
968.
小波图像编码的VLSI实现 总被引:1,自引:0,他引:1
设计了一种模块化的二维离散小波变换(2-D DWT)的VLSI结构.该结构可以实时完成小波变换,且很容易扩展.针对零树编码硬件实现方面的不足,利用一种简单的顺序扫描方式和两个标志阵列,设计了一种适合硬件实现的快速零树编码算法(FZIC)和FZIC硬件实现的VLSI结构,编写了2-D DWT和FZIC硬件结构的Veri log HDL模型,并进行了仿真和逻辑综合.结合2-D DWT和FZIC,实现了小波图像编码系统 ,并用ALTERA CPLD成功进行了验证. 相似文献
969.
宽带IP城域网及其应用 总被引:1,自引:0,他引:1
文章结合南京电信公众宽带IP城域网的建设,对宽带IP城域网的网络结构、用户接入安全、网络管理和认证计费作了阐述,并简要介绍了应用于宽带IP城域网上的一些业务。 相似文献
970.
Animated pedagogical agents in multimedia educational environments: Effects of agent properties, picture features and redundancy. 总被引:2,自引:0,他引:2
Two experiments explored the integration of animated agents into multimedia environments in the context of R. E. Mayer's (2001) cognitive theory of multimedia learning. Experiment 1 was a 3 (agent properties: agent only, agent with gesture, no agent) × 3 (picture features: static picture, sudden onset, animation) design. Agent properties produced no significant effects. Both sudden onset and animation conditions facilitated performance relative to the static-picture condition. In Experiment 2, we explored the effects of printed text, spoken narration, and spoken narration with the printed text, in a multimedia environment that included an agent, to investigate effects of redundancy. The spoken-narration-only condition outperformed the other 2, with no differences between printed text and printed text with spoken narration. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献