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   1166篇
  免费   69篇
  国内免费   7篇
电工技术   8篇
化学工业   285篇
金属工艺   20篇
机械仪表   16篇
建筑科学   9篇
能源动力   40篇
轻工业   297篇
水利工程   5篇
石油天然气   2篇
无线电   128篇
一般工业技术   216篇
冶金工业   72篇
原子能技术   3篇
自动化技术   141篇
  2024年   10篇
  2023年   26篇
  2022年   87篇
  2021年   96篇
  2020年   81篇
  2019年   82篇
  2018年   90篇
  2017年   59篇
  2016年   54篇
  2015年   58篇
  2014年   54篇
  2013年   73篇
  2012年   45篇
  2011年   48篇
  2010年   47篇
  2009年   38篇
  2008年   37篇
  2007年   32篇
  2006年   21篇
  2005年   11篇
  2004年   15篇
  2003年   5篇
  2002年   12篇
  2001年   6篇
  2000年   12篇
  1999年   9篇
  1998年   21篇
  1997年   18篇
  1996年   13篇
  1995年   8篇
  1994年   10篇
  1993年   10篇
  1992年   8篇
  1991年   9篇
  1990年   3篇
  1989年   3篇
  1988年   2篇
  1987年   2篇
  1986年   5篇
  1985年   3篇
  1984年   1篇
  1983年   1篇
  1982年   2篇
  1981年   4篇
  1980年   1篇
  1979年   3篇
  1978年   3篇
  1977年   1篇
  1976年   2篇
  1974年   1篇
排序方式: 共有1242条查询结果,搜索用时 0 毫秒
21.
Wireless Personal Communications - In this paper, a rack shaped two radiator element multiple input multiple output (MIMO) dielectric resonator antenna (DRA) is reported with improved axial ratio...  相似文献   
22.
Artificial Intelligence Review - Nowadays we see huge amount of information is available on both, online and offline sources. For single topic we see hundreds of articles are available, containing...  相似文献   
23.
Multimedia Tools and Applications - The entire community of medical experts uses various imaging techniques as the precursor for disease diagnosis with the assistance of computer-aided diagnosis...  相似文献   
24.
This paper proposes a new robust exponential sliding mode differentiator for estimating the (n ? 1) derivatives of a non‐linear function. Finite time convergence, robustness, and exactness are also ensured analytically with the proposed methodology. In addition, the results of the proposed sliding mode differentiator are extended to derive theorems for the novel state (SO) and extended state observers (ESO), which would estimate the system states as well as uncertainties recursively in finite time. Finally, three examples are implemented to validate the proposed methodologies and the obtained simulations are compared with the previously developed methods in literature.  相似文献   
25.

The data flow is an important parameter used in the optimization problem of Wireless Sensor Networks. This paper presents an expert approach for improved data flow prediction based on data discretization and artificial intelligence. The proposed approach has been implemented on various machine learning methods (a total of 17 methods). This data flow prediction is based on the dataset generated from the simulations with NS-2.35 for multiple Wireless Sensor Networks (5- to -50 nodes). The performance comparison of different machine learning models with continuous data and discretized data is also presented. The proposed approach considerably reduces the execution time of the machine learning models for training purposes and also enhances the accuracy of prediction. The result analysis shows that the proposed approach is better compared to various machine learning methods. Also, the proposed approach is able to handle both continuous and discrete data. The datasets used in this work are available as a supplement at NDS and DDS link.

  相似文献   
26.
27.
Food Science and Biotechnology - The objective of this study was to perform genetic diversity analysis of 13 strains isolated from South Korean foods by multilocus sequence typing (MLST). For...  相似文献   
28.
This article presents a neural–network-based fuzzy logic control (NN–FLC) system. The NN–FLC model has the learning capabilities for constructing membership functions and extracting fuzzy rules from training examples. Both unsupervised and supervised training algorithms are used to find the membership functions of the FLC. Competitive learning algorithms are employed to evaluate fuzzy logic rules. Matlab programs using both neural and fuzzy toolboxes are developed to implement the NN–FLC model. Computer simulations of the inverted pendulum controlled by NN–FLC system were conducted to illustrate the self-learning ability of the network. © 1998 John Wiley & Sons, Inc.13: 11–26, 1998  相似文献   
29.
The effect of irrigation on the lipid composition in maturing taramira (Eruca sativa, Mill) seed was studied. Decreasing the number of irrigations had an adverse effect on oil setting. Restricted irrigations affected adversely the biosynthesis of erucic acid in the oil at initial stages, though at later stages of seed development, irrigation had no such effect.  相似文献   
30.
The optical and electrical properties of the conducting polymer poly(3-hexylthiophene) and single walled carbon nanotube (SWCNT) composites have been investigated. The composites were prepared by dispersing carbon nanotubes in the polymer matrix already dissolved in 1,2-dichlorobenzene. The optical absorption, photoluminescence (PL) and electrical conductivity of the composite was studied as a function of SWCNT concentration in the solution. The absorption coefficient of the polymer was found to be unaffected upto a SWCNT concentration 5% w/w. However a minor decrease in the absorption in visible region was observed for higher SWCNT concentrations. The intensity of PL emission from the composite was measured and was found to decrease with the increase in SWCNT concentration. For a SWCNT concentration of 30% w/w, ∼90% of the PL was quenched, indicating an ultra fast transfer of photoinduced charges from donor polymer to acceptor SWCNT. Direct current conductivity of the composite film was found to increase rapidly with the increase in SWCNT concentration and an increase of ∼5 orders of magnitude was observed for a 30% w/w concentration. The enhancement in conductivity is explained in terms of percolation theory with an estimated percolation threshold of 2% w/w.  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