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   52613篇
  免费   6693篇
  国内免费   3792篇
电工技术   5278篇
技术理论   1篇
综合类   4224篇
化学工业   7508篇
金属工艺   3029篇
机械仪表   3399篇
建筑科学   4218篇
矿业工程   1910篇
能源动力   1539篇
轻工业   4170篇
水利工程   1465篇
石油天然气   2607篇
武器工业   674篇
无线电   6572篇
一般工业技术   5715篇
冶金工业   1992篇
原子能技术   552篇
自动化技术   8245篇
  2024年   420篇
  2023年   1416篇
  2022年   2750篇
  2021年   3752篇
  2020年   2589篇
  2019年   1934篇
  2018年   1963篇
  2017年   2161篇
  2016年   1929篇
  2015年   2625篇
  2014年   3142篇
  2013年   3511篇
  2012年   4170篇
  2011年   4242篇
  2010年   3697篇
  2009年   3442篇
  2008年   3347篇
  2007年   3034篇
  2006年   2698篇
  2005年   2357篇
  2004年   1479篇
  2003年   1108篇
  2002年   1011篇
  2001年   867篇
  2000年   767篇
  1999年   625篇
  1998年   397篇
  1997年   341篇
  1996年   306篇
  1995年   239篇
  1994年   206篇
  1993年   122篇
  1992年   102篇
  1991年   78篇
  1990年   57篇
  1989年   41篇
  1988年   33篇
  1987年   25篇
  1986年   32篇
  1985年   11篇
  1984年   9篇
  1983年   2篇
  1982年   11篇
  1981年   8篇
  1980年   11篇
  1979年   13篇
  1975年   1篇
  1973年   1篇
  1959年   8篇
  1951年   7篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
阐述"一体化技能双证书"课程模式对技工院校计算机网络专业教学改革的重要意义,分析当前计算机网络相关职业资格证书存在的问题,把知名行业企业认证培训融合进计算机网络专业一体化教学改革中。  相似文献   
42.
43.
介绍了领域本体构建的基本流程,目的是为了更好地服务于语义web以及搜索引擎等。主要内容包括本体的概念、分类、功能及本体构建的方法、语言和工具,并以Java领域本体库的构建为例详细阐述了本体的构建过程。  相似文献   
44.
An appropriate assessment of end-to-end network performance presumes highly efficient time tracking and measurement with precise time control of the stopping and resuming of program operation. In this paper, a novel approach to solving the problems of highly efficient and precise time measurements on PC-platforms and on ARM-architectures is proposed. A new unified High Performance Timer and a corresponding software library offer a unified interface to the known time counters and automatically identify the fastest and most reliable time source, available in the user space of a computing system. The research is focused on developing an approach of unified time acquisition from the PC hardware and accordingly substituting the common way of getting the time value through Linux system calls. The presented approach provides a much faster means of obtaining the time values with a nanosecond precision than by using conventional means. Moreover, it is capable of handling the sequential time value, precise sleep functions and process resuming. This ability means the reduction of wasting computer resources during the execution of a sleeping process from 100% (busy-wait) to 1-1.5%, whereas the benefits of very accurate process resuming times on long waits are maintained.  相似文献   
45.
Various molecular docking software packages are available for modeling interactions between small molecules and proteins.However,there have been few reports of modeling the interactions between metal ions and metalloproteins.In this study,the AutoDock package was employed to example docking into a di-iron binding protein,bacterioferritin.Each binding site of this protein was tested for docking with iron ions.Blind docking experiments showed that all docking conformations converged into two clusters,one for internal iron binding in sites within the metalloprotein and the other for external iron binding on the protein surface.Local docking experiments showed that there were significant differences between two internal iron binding sites.Docking at one site gave a reasonable root-mean-square deviation(RMSD) distribution with relatively low binding energy.Analysis of the binding mode quality for this site revealed that more than half of the docking conformations were categorized as having good binding geometry,while no good conformations were found for the other site.Further investigations indicated that coordinating water molecules contributed to the stability of binding geometries.This study provides an empirical approach towards the study of molecular docking in metalloproteins.  相似文献   
46.
47.
实验教学是高职计算机网络课程的重要组成部分,目前高职计算机网络实验课程开展困难,效果不明显。该文结合当前高职计算机网络课程实验教学的现状,谈一谈如何利用Packet Tracer模拟软件提高《网络互联技术》课程的实验教学效果。  相似文献   
48.
向昊  徐家恺 《微处理机》2008,29(1):11-13
主要介绍基于便携式设备的RDS调频收音模块的设计,着重讲述了有关FM接收、RDS数据接收与音频处理等方面的应用电路。  相似文献   
49.
Despite the outstanding power conversion efficiency (PCE) of perovskite solar cells (PSCs) achieved over the years, unsatisfactory stability and lead toxicity remain obstacles that limit their competitiveness and large-scale practical deployment. In this study, in situ polymerizing internal encapsulation (IPIE) is developed as a holistic approach to overcome these challenges. The uniform polymer internal package layer constructed by thermally triggered cross-linkable monomers not only solidifies the ionic perovskite crystalline by strong electron-withdrawing/donating chemical sites, but also acts as a water penetration and ion migration barrier to prolong shelf life under harsh environments. The optimized MAPbI3 and FAPbI3 devices with IPIE treatment yield impressive efficiencies of 22.29% and 24.12%, respectively, accompanied by remarkably enhanced environmental and mechanical stabilities. In addition, toxic water-soluble lead leakage is minimized by the synergetic effect of the physical encapsulation wall and chemical chelation conferred by the IPIE. Hence, this strategy provides a feasible route for preparing efficient, stable, and eco-friendly PSCs.  相似文献   
50.
Lin  Songyue  Hao  Xuejiang  Liu  Yan  Yan  Dong  Liu  Jianwei  Zhong  Mingjun 《Neural computing & applications》2023,35(11):8295-8306
Neural Computing and Applications - Dental X-ray image segmentation is helpful for assisting clinicians to examine tooth conditions and identify dental diseases. Fast and lightweight segmentation...  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