全文获取类型
收费全文 | 495167篇 |
免费 | 5965篇 |
国内免费 | 2366篇 |
专业分类
电工技术 | 9098篇 |
综合类 | 779篇 |
化学工业 | 72474篇 |
金属工艺 | 20720篇 |
机械仪表 | 14559篇 |
建筑科学 | 12107篇 |
矿业工程 | 2013篇 |
能源动力 | 12433篇 |
轻工业 | 43965篇 |
水利工程 | 4639篇 |
石油天然气 | 7013篇 |
武器工业 | 46篇 |
无线电 | 59976篇 |
一般工业技术 | 96189篇 |
冶金工业 | 96233篇 |
原子能技术 | 10753篇 |
自动化技术 | 40501篇 |
出版年
2021年 | 3635篇 |
2019年 | 3395篇 |
2018年 | 5797篇 |
2017年 | 5806篇 |
2016年 | 6233篇 |
2015年 | 4341篇 |
2014年 | 7266篇 |
2013年 | 21905篇 |
2012年 | 11971篇 |
2011年 | 16671篇 |
2010年 | 13191篇 |
2009年 | 14975篇 |
2008年 | 15753篇 |
2007年 | 15849篇 |
2006年 | 13964篇 |
2005年 | 12876篇 |
2004年 | 12640篇 |
2003年 | 12401篇 |
2002年 | 12157篇 |
2001年 | 12302篇 |
2000年 | 11443篇 |
1999年 | 12338篇 |
1998年 | 31019篇 |
1997年 | 21904篇 |
1996年 | 16790篇 |
1995年 | 12644篇 |
1994年 | 11163篇 |
1993年 | 11075篇 |
1992年 | 7950篇 |
1991年 | 7700篇 |
1990年 | 7218篇 |
1989年 | 7104篇 |
1988年 | 6789篇 |
1987年 | 5960篇 |
1986年 | 5926篇 |
1985年 | 6773篇 |
1984年 | 6173篇 |
1983年 | 5670篇 |
1982年 | 5304篇 |
1981年 | 5337篇 |
1980年 | 5173篇 |
1979年 | 4856篇 |
1978年 | 4899篇 |
1977年 | 5718篇 |
1976年 | 7946篇 |
1975年 | 4125篇 |
1974年 | 4015篇 |
1973年 | 4039篇 |
1972年 | 3341篇 |
1971年 | 2969篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
111.
Moser L.E. Melliar-Smith P.M. Agrawala V. 《Parallel and Distributed Systems, IEEE Transactions on》1994,5(5):459-473
Presents protocols for determining processor membership in asynchronous distributed systems that are subject to processor and communication faults. These protocols depend on the placement of a total order on broadcast messages. The types of systems for which each of these protocols is applicable are characterized by the properties of the communication mechanisms and by the availability of stable storage. In the absence of stable storage or of a mechanism for distinguishing promptly delivered messages, the authors show that no membership protocol can exist. They also discuss their experience in implementing these membership protocols 相似文献
112.
Ju D.-C.R. Chuan-Lin Wu Carini P. 《Parallel and Distributed Systems, IEEE Transactions on》1994,5(10):1113-1120
We present a classification scheme for array language primitives that quantifies the variation in parallelism and data locality that results from the fusion of any two primitives. We also present an algorithm based on this scheme that efficiently determines when it is beneficial to fuse any two primitives. Experimental results show that five LINPACK routines report 50% performance improvement from the fusion of array operators 相似文献
113.
McKinley P.K. Xu H. Esfahanian A.-H. Ni L.M. 《Parallel and Distributed Systems, IEEE Transactions on》1994,5(12):1252-1265
Multicast communication, in which the same message is delivered from a source node to an arbitrary number of destination nodes, is being increasingly demanded in parallel computing. System supported multicast services can potentially offer improved performance, increased functionality, and simplified programming, and may in turn be used to support various higher-level operations for data movement and global process control. This paper presents efficient algorithms to implement multicast communication in wormhole-routed direct networks, in the absence of hardware multicast support, by exploiting the properties of the switching technology. Minimum-time multicast algorithms are presented for n-dimensional meshes and hypercubes that use deterministic, dimension-ordered routing of unicast messages. Both algorithms can deliver a multicast message to m-1 destinations in [log 2 m] message passing steps, while avoiding contention among the constituent unicast messages. Performance results of implementations on a 64-node nCUBE-2 hypercube and a 168-node Symult 2010 2-D mesh are given 相似文献
114.
Implementing a neural network on a digital or mixed analog and digital chip yields the quantization of the synaptic weights dynamics. This paper addresses this topic in the case of Kohonen's self-organizing maps. We first study qualitatively how the quantization affects the convergence and the properties, and deduce from this analysis the way to choose the parameters of the network (adaptation gain and neighborhood). We show that a spatially decreasing neighborhood function is far more preferable than the usually rectangular neighborhood function, because of the weight quantization. Based on these results, an analog nonlinear network, integrated in a standard CMOS technology, and implementing this spatially decreasing neighborhood function is then presented. It can be used in a mixed analog and digital circuit implementation. 相似文献
115.
We have developed a problem-solving framework, called ConClass, that is capable of classifying continuous real-time problems dynamically and concurrently on a distributed system. ConClass provides an efficient development environment for describing and decomposing a classification problem and synthesizing solutions. In ConClass, decomposed concurrent subproblems specified by the application developer effectively correspond to the actual distributed hardware elements. This scheme is useful for designing and implementing efficient distributed processing, making it easier to anticipate and evaluate system behavior. The ConClass system provides an object replication feature that prevents any particular object from being overloaded. In order to deal with an indeterminate amount of problem data, ConClass dynamically creates object networks that justify hypothesized solutions, and thus achieves a dynamic load distribution. A number of efficient execution mechanisms that manage a variety of asynchronous aspects of distributed processing have been implemented without using schedulers or synchronization schemes that are liable to develop bottlenecks. We have confirmed the efficiency of parallel distributed processing and load balancing of ConClass with an experimental application 相似文献
116.
Silicon nitride corrugated diaphragms of 2 mm×2 mm×1 μm have been fabricated with 8 circular corrugations, having depths of 4, 10, or 14 μm. The diaphragms with 4-μm-deep corrugations show a measured mechanical sensitivity (increase in the deflection over the increase in the applied pressure) which is 25 times larger than the mechanical sensitivity of flat diaphragms of equal size and thickness. Since this gain in sensitivity is due to reduction of the initial stress, the sensitivity can only increase in the case of diaphragms with initial stress. A simple analytical model has been proposed that takes the influence of initial tensile stress into account. The model predicts that the presence of corrugations increases the sensitivity of the diaphragms, because the initial diaphragm stress is reduced. The model also predicts that for corrugations with a larger depth the sensitivity decreases, because the bending stiffness of the corrugations then becomes dominant. These predictions have been confirmed by experiments. The application of corrugated diaphragms offers the possibility to control the sensitivity of thin diaphragms by geometrical parameters, thus eliminating the effect of variations in the initial stress, due to variations in the diaphragm deposition process and/or the influence of temperature changes and packaging stress 相似文献
117.
What is the implication for business when information technology (IT) changes in the workplace without a commensurate change in the composition of business programs educating tomorrow's employees? A survey of MBA graduates forms the basis of this article on the IT skills needed in the marketplace. 相似文献
118.
119.
This paper is a reply to Laviolette and Seaman's critical discussion of fuzzy set theory. Rather than questioning the interest of the Bayesian approach to uncertainty, some reasons why Bayesian find the idea of a fuzzy set not palatable are laid bare. Some links between fuzzy sets and probability that Laviolette and Seaman seem not to be aware of are pointed out. These links suggest that, contrary to the claim sometimes found in the literature, probability theory is not a special case of fuzzy set theory. The major objection to Laviolette and Seaman is that they found their critique on as very limited view of fuzzy sets, including debatable papers, while they fail to account for significant works pertaining to axiomatic derivation of fuzzy set connectives, possibility theory, fuzzy random variables, among others 相似文献
120.
In the editorial by J.C. Bezdek (ibid., p.1), an example is presented to demonstrate differences between fuzzy membership and probability. The authors argue that probability can be used in a way much more closely analogous to this use of fuzzy membership, weakening the argument for the latter 相似文献