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   12746篇
  免费   1060篇
  国内免费   533篇
电工技术   644篇
技术理论   1篇
综合类   968篇
化学工业   2116篇
金属工艺   632篇
机械仪表   759篇
建筑科学   1064篇
矿业工程   358篇
能源动力   487篇
轻工业   806篇
水利工程   243篇
石油天然气   777篇
武器工业   102篇
无线电   1425篇
一般工业技术   1576篇
冶金工业   553篇
原子能技术   140篇
自动化技术   1688篇
  2024年   41篇
  2023年   206篇
  2022年   310篇
  2021年   444篇
  2020年   418篇
  2019年   321篇
  2018年   376篇
  2017年   380篇
  2016年   405篇
  2015年   478篇
  2014年   592篇
  2013年   672篇
  2012年   743篇
  2011年   775篇
  2010年   717篇
  2009年   699篇
  2008年   638篇
  2007年   587篇
  2006年   586篇
  2005年   519篇
  2004年   418篇
  2003年   517篇
  2002年   633篇
  2001年   545篇
  2000年   414篇
  1999年   352篇
  1998年   278篇
  1997年   252篇
  1996年   221篇
  1995年   171篇
  1994年   139篇
  1993年   106篇
  1992年   83篇
  1991年   69篇
  1990年   54篇
  1989年   33篇
  1988年   44篇
  1987年   23篇
  1986年   20篇
  1985年   18篇
  1984年   8篇
  1983年   7篇
  1982年   8篇
  1981年   4篇
  1980年   6篇
  1979年   4篇
  1978年   2篇
  1977年   1篇
  1974年   1篇
  1961年   1篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
11.
Terpolymers based on N‐isopropylacrylamide, sodium 2‐acrylamido‐2‐methyl‐propanesulfonate, and Ntert‐butylacrylamide were synthesized by free‐radical copolymerization with 2,2′‐azobisisobutyronitrile as an initiator. The lower critical solution temperatures (LCSTs) of the linear polymer aqueous solutions were determined by the measurement of the transmittance on UV at different temperatures. The influence of the polymer concentration, polymer composition, and ionic strength on the LCSTs of the linear polymers was investigated. The LCST decreased with increases in the hydrophobic monomer Ntert‐butylacrylamide, polymer concentration, and ionic strength. The phase transition became sharp when the polymer concentration and ionic strength increased. Meanwhile, the crosslinked hydrogels were prepared with the same recipe used for the linear terpolymers, but a crosslinker was added to the reaction system. The swelling ratios of the hydrogels at various temperatures and salt solutions were determined. The hydrogels possessed both high swelling ratios and thermosensitivity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007  相似文献   
12.
本文介绍了一个微机上运行的注塑模CAD系统,此系统主要解决了四个难点,浇注系统设计,冷却系统分析,型腔,型芯的曲面造型设计,装配图和零件工作图的设计绘制,经厂家实际运用证明,该系统使用方便,结果正确,能提高设计效率,降低生产成本。  相似文献   
13.
The corrosion behavior of pure aluminum in inhibited and uninhibited 4 MKOH was investigated by means of hydrogen collection, polarization curve measurement and electrochemical impedance spectroscopy (EIS). The results showed that the corrosion of pure aluminum was greatly inhibited by the addition of ZnO and dimethyl amine epoxy propane (designated as DE). EIS and EDAX analyses revealed that ZnO produces its effect by depositing on the aluminum surface, which increases the overpotential of hydrogen evolution. It was also found that the addition of DE could greatly improve the deposition of zinc layers.  相似文献   
14.
Machine Intelligence Research - One of the most significant challenges in the neuroscience community is to understand how the human brain works. Recent progress in neuroimaging techniques have...  相似文献   
15.
Accelerated electrospark deposition and the wear behavior of coatings   总被引:5,自引:0,他引:5  
Electrospark deposition (ESD) is a coating process that is featured by low heat input to the substrate. Low coating efficiency and other limitations influence its wider application. The present paper introduces newly designed ESD equipment, by which a higher coating rate can be reached. The relationship among coating thickness, surface roughness, and process parameters such as pulse energy, pulse frequency, and deposition time are presented. Electrospark deposition coating by the new equipment on AISI 1045 steel (with WC-8% Co as electrode) increases the wear resistance by 5 to 8 times. The micromechanism is investigated by scanning electron microscopy observation.  相似文献   
16.
The process of aging precipitation in SiC_p/6061 and Al_2O_3/6061 composites were investigated. Hardness testing, differential scanning calorimetry(DSC) and transmission electron microscopy were employed. Results showed that the precipitation phase form directly along dislocation lines in the composites because the particles produce high densities of dislocations which makes vacancy densities in the composites decrease, and the main precipitation phase at peak hardness was β′ phase.  相似文献   
17.
Since the harmonic components in the signal to be analyzed are uncertain and diverse, it is difficult to make the sampling frequency and the signal length be harmonically related to the component frequencies included in the signal, and the leakage is produced in the discrete Fourier transform. Based on the definition of the Herfindahl index in economics, the spectrum concentration can be defined and computed. The appropriate number of points can be decided according to the peak location of the spectrum concentration. The method and the examples are specified in detail in the paper.  相似文献   
18.
Zhang  Man  Zhou  Yong  Liu  Bing  Zhao  Jiaqi  Yao  Rui  Shao  Zhiwen  Zhu  Hancheng  Chen  Hao 《Pattern Analysis & Applications》2023,26(2):669-677
Pattern Analysis and Applications - The designed method aims to perform image classification tasks efficiently and accurately. Different from the traditional CNN-based image classification methods,...  相似文献   
19.
International Journal of Computer Vision - Visual tracking of generic objects is one of the fundamental but challenging problems in computer vision. Here, we propose a novel fully convolutional...  相似文献   
20.
Internet of Vehicles (IoV) applications integrating with edge computing will significantly drive the growth of IoV. However, the contradiction between the high-speed mobility of vehicles, the delay sensitivity of corresponding IoV applications and the limited coverage and resource capacity of distributed edge servers will pose challenges to the service continuity and stability of IoV applications. IoV application migration is a promising solution that can be supported by application containerization, a technology forseamless cross-edge-server application migration without user perception. Therefore, this paper proposes the container-based IoV edge application migration mechanism, consisting of three parts. The first is the migration trigger determination algorithm for cross-border migration and service degradation migration, respectively, based on trajectory prediction and traffic awareness to improve the determination accuracy. The second is the migration target decision calculation model for minimizing the average migration time and maximizing the average service time to reduce migration times and improve the stability and adaptability of migration decisions. The third is the migration decision algorithm based on the improved artificial bee colony algorithm to avoid local optimal migration decisions. Simulation results show that the proposed migration mechanism can reduce migration times, reduce average migration time, improve average service time and enhance the stability and adaptability of IoV application services.  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