首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   525103篇
  免费   5004篇
  国内免费   1050篇
电工技术   8274篇
综合类   2651篇
化学工业   82643篇
金属工艺   26182篇
机械仪表   18285篇
建筑科学   11126篇
矿业工程   5073篇
能源动力   9558篇
轻工业   36063篇
水利工程   7246篇
石油天然气   15700篇
武器工业   55篇
无线电   49959篇
一般工业技术   111873篇
冶金工业   74186篇
原子能技术   14926篇
自动化技术   57357篇
  2021年   4240篇
  2019年   4092篇
  2018年   21438篇
  2017年   20606篇
  2016年   17826篇
  2015年   5209篇
  2014年   8258篇
  2013年   18551篇
  2012年   14931篇
  2011年   24420篇
  2010年   20306篇
  2009年   19027篇
  2008年   20659篇
  2007年   21488篇
  2006年   12064篇
  2005年   11610篇
  2004年   11303篇
  2003年   11015篇
  2002年   10408篇
  2001年   9713篇
  2000年   9610篇
  1999年   8904篇
  1998年   18712篇
  1997年   13838篇
  1996年   10672篇
  1995年   8479篇
  1994年   7717篇
  1993年   7729篇
  1992年   6391篇
  1991年   6217篇
  1990年   6455篇
  1989年   6261篇
  1988年   6031篇
  1987年   5632篇
  1986年   5583篇
  1985年   6141篇
  1984年   5928篇
  1983年   5567篇
  1982年   5251篇
  1981年   5347篇
  1980年   5275篇
  1979年   5383篇
  1978年   5571篇
  1977年   5882篇
  1976年   7093篇
  1975年   5032篇
  1974年   5041篇
  1973年   5153篇
  1972年   4499篇
  1971年   4149篇
排序方式: 共有10000条查询结果,搜索用时 69 毫秒
71.
The capacitive idling converters derived from the Cuk, SEPIC, Zeta, and flyback topologies allow soft commutation of power switches without the need for additional circuitry, making it possible to increase the switching frequency while maintaining high efficiency  相似文献   
72.
73.
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   
74.
We present the design of E-kernel, an embedding kernel on the Victor V256 message-passing partitionable multiprocessor, developed for the support of program mapping and network reconfiguration. E-kernel supports the embedding of a new network topology onto Victor's 2D mesh and also the embedding of a task graph onto the 2D mesh network or the reconfigured network. In the current implementation, the reconfigured network can be a line or an even-size ring, and the task graphs meshes or tori of a variety of dimensions and shapes or graphs with similar topologies. For application programs having these task graph topologies and that are designed according to the communication model of E-kernel, they can be run without any change on partitions connected by the 2D mesh, line, or ring. Further, E-kernel attempts the communication optimization of these programs on the different networks automatically, thus making both the network topology and the communication optimization attempt completely transparent to the application programs. Many of the embeddings used in E-kernel are optimal or asymptotically optimal (with respect to minimum dilation cost). The implementation of E-kernel translated some of the many theoretical results in graph embeddings into practical tools for program mapping and network reconfiguration in a parallel system. E-kernel is functional on Victor V256. Measurements of E-kernel's performance on V256 are also included  相似文献   
75.
Genetic evolution of the topology and weight distribution of neuralnetworks   总被引:52,自引:0,他引:52  
This paper proposes a system based on a parallel genetic algorithm with enhanced encoding and operational abilities. The system, used to evolve feedforward artificial neural networks, has been applied to two widely different problem areas: Boolean function learning and robot control. It is shown that the good results obtained in both cases are due to two factors: first, the enhanced exploration abilities provided by the search-space reducing evolution of both coding granularity and network topology, and, second, the enhanced exploitational abilities due to a recently proposed cooperative local optimizing genetic operator.  相似文献   
76.
Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 95–112, March–April, 1994.  相似文献   
77.
This research was supported under project No. 6.02.02/128-93 as part of the state scientific-technical program on future information technologies and systems by the Ukrainian State Committee, of Science and Technology.  相似文献   
78.
79.
80.
Carstensen and Rhodes1 have suggested that when, in stability programs, assays cannot be performed immediately after the protocol-designated storage time, then freezing them until such a time when assays can be performed would be a reasonable manner to retain the protocol schedule. They caution, however, that such a procedure may not be valid for dissolution data. The article to follow deals with real-time data showing that such a process is feasible for Nalidixic Acid tablets (and presumably for other tablets as well), and that, furthermore, the dissolution pattern would seem to be “frozen” as well.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号