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   599篇
  免费   20篇
  国内免费   2篇
电工技术   8篇
综合类   1篇
化学工业   80篇
金属工艺   18篇
机械仪表   14篇
建筑科学   25篇
能源动力   60篇
轻工业   46篇
水利工程   3篇
石油天然气   1篇
无线电   75篇
一般工业技术   122篇
冶金工业   33篇
原子能技术   6篇
自动化技术   129篇
  2024年   3篇
  2023年   9篇
  2022年   19篇
  2021年   41篇
  2020年   24篇
  2019年   28篇
  2018年   29篇
  2017年   38篇
  2016年   27篇
  2015年   15篇
  2014年   25篇
  2013年   51篇
  2012年   25篇
  2011年   20篇
  2010年   28篇
  2009年   28篇
  2008年   20篇
  2007年   14篇
  2006年   10篇
  2005年   16篇
  2004年   15篇
  2003年   12篇
  2002年   6篇
  2001年   3篇
  2000年   4篇
  1999年   4篇
  1998年   10篇
  1997年   10篇
  1996年   11篇
  1995年   3篇
  1994年   5篇
  1993年   5篇
  1992年   3篇
  1991年   2篇
  1990年   2篇
  1989年   7篇
  1988年   4篇
  1987年   3篇
  1986年   4篇
  1985年   4篇
  1984年   1篇
  1983年   2篇
  1982年   5篇
  1981年   4篇
  1979年   3篇
  1977年   3篇
  1976年   9篇
  1975年   1篇
  1973年   3篇
  1972年   3篇
排序方式: 共有621条查询结果,搜索用时 312 毫秒
501.

In wireless sensor networks, the overlapped sub-regions (faces) are generated due to the intersections among the sensing ranges of nodes. The faces play a significant role in solving the three problems k-coverage (i.e., all the points in the interested field should be covered by at least k active nodes while maintaining connectivity between all active nodes), coverage scheduling and cover sets. To find the faces and discover their coverage degrees, this article presents a distributed algorithm that runs in three steps. First, a colored graph called Intersection Points Colored Graph (IPCG) is proposed, in which the vertices are defined by the range-intersections of nodes-devices and are colored according to the position of these intersections in relation to the ranges of the nodes. The vertex that located on perimeter of the node’s range is colored by red, while the green vertex is an intersection of two ranges inside the range of a third node. The edge that joins two red vertices is colored by red and the edge that joins two green vertices is colored by green while the edge that joins two distinct colored vertices is colored by blue. Second, based on their properties and distinct features, the faces in IPCG are classified into five classes (simple, negative, red, green and positive). Third, based on faces classification, the Three Colored Trees algorithm is proposed to extract the faces in linear time in terms of the number of vertices and edges in IPCG.

  相似文献   
502.
Herein, the synthesis, characterizations and gas sensor application of nano-textured urchin like CuO hollow microspheres (HM) were reported. The detailed characterizations confirmed the uniform growth and nanocrystalline monoclinic structure of urchin like CuO HM. The synthesized urchins like CuO HM were utilized to fabricate resistive sensor devices which exhibited elevated response towards ethanol with high selectivity. The optimization of operating temperature was carried out for the highest ethanol response and the effect of different concentrations were also recorded. The sensor device showed 1241% response at an operating temperature of 225 °C for 100 ppm ethanol concentration. The lowest ethanol was detected at 25 ppm having the response of 49% by the fabricated CuO sensor device. Transient responses as well as stability of the sensor were analyzed. The selectivity of CuO sensor device was studied for NO2, CO2, CH4 and H2 gases and remarkably it was seen that the developed gas sensor devices demonstrated outstanding selectivity towards ethanol gas. Finally, the density functional theory (DFT) computational quantum modelling was utilized in order to understand the adsorption phenomenon of ethanol and oxygen molecules in the sensing application. An ethanol sensing mechanism using CuO sensor was also elucidated.  相似文献   
503.
Wang  Lin  Wang  Xingfu  Hawbani  Ammar  Xiong  Yan  Zhang  Xu 《Multimedia Tools and Applications》2022,81(9):12157-12176

Recently, two-stream networks with multi-modality inputs have shown to be of vital importance for state-of-the-art video understanding. Previous deep systems typically employ a late fusion strategy, however, despite its simplicity and effectiveness, the late strategy might experience insufficient fusion due to that it performs fusion across modalities only once and treats each modality equally without discrimination. In this paper, we propose a Discriminative Dense Fusion (D2F) network, addressing these limitations by densely inserting an attention-based fusion block at each layer. We experiment with two typical action classification benchmarks and three popular classification backbones, where our proposed module consistently outperforms state-of-the-art baselines by noticeable margins. Specifically, the two-stream VGG16, ResNet and I3D achieve accuracy of [93.5%, 69.2%], [94.6%, 70.5%], [94.1%, 72.3%] with D2F on [UCF101, HMDB51], respectively, with absolute gains of [5.5%, 9.8%], [5.13%, 9.91%], and [0.7%, 5.9%] compared with their late fusion counterparts. The qualitative performance also demonstrates that our model can learn more informative complementary representation.

  相似文献   
504.
505.
Neural Computing and Applications - Botnet is a thorny and a grave problem of today’s Internet, resulting in economic damage for organizations and individuals. Botnet is a group of...  相似文献   
506.
This study was conducted to compare metals bioaccumulation in the terrestrial isopod Armadillidium granulatum collected from Ghar El Melh lagoon. We focused on recognizing the effects of trace elements on hepatopancreas functional role. To this end, isopod specimens were exposed for 3 weeks to sediments contaminated with cadmium, copper, zinc, mercury, and nickel. Three concentrations were used in duplicate for each experimental condition. At the end of the experiment, metal body burdens were determined using flame atomic absorption spectrometry. Results of the bioaccumulation factor (BAF) showed that the species A. granulatum was classified as a Cu macroconcentrator (BAF > 2) and a Zn deconcentrator (BAF < 2). Dose dependent morphological and histological changes were observed in the hepatopancreas cells using transmission electron microscopy. The predominant features were: microvillus border disruption, condensation of the cytoplasm with increasing endoplasmic reticulum, mitochondria, lysosomes and granules that accumulated metals in B and S cells. The number of lipid droplets decreased especially after Cd, Zn, Hg, and Ni treatments. This study demonstrated that the terrestrial isopod A. gramulatum could be a good indicator of soil metal contamination.  相似文献   
507.
Journal of Intelligent Information Systems - Recently, there has been an enormous increase in the number of reviews of popular products. Therefore, opinion analysis has become a tedious task for...  相似文献   
508.
The aim of the present work was to study the effect of season on phospholipids and triacylglycerols (TAG) of mantle and tentacles of female and male wild Sepia officinalis. The identified phospholipids were phosphatidylethanolamine (PtdEtn), phosphatidylcholine (PtdCho), phosphatidylserine (PtdSer), and phosphatidylinositol (PtdIns), and PtdEtn was the major fraction. Results showed apparent seasonal variation of phospholipid content, particularly with female samples. Fatty acid composition of phospholipid classes showed a differentiation much more in the proportions than in the diversity of fatty acids. Results showed that the major saturated fatty acids were 16:0 and 18:0, the major monounsaturated fatty acids were 18:1 and 20:l, and the major polyunsaturated fatty acids were docosahexaenoic acid (22:6n-3) (DHA) and eicosapentaenoic acid (20:5n-3) (EPA). The results relative to TAG demonstrated significant variations. Principal component analysis confirmed the seasonal and sexual effects. This study could be appropriate for the improvement of consistent monitoring of phospholipid and TAG accumulation in cephalopod, which might be important for both physiological studies and food industries.  相似文献   
509.
510.
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