全文获取类型
收费全文 | 38228篇 |
免费 | 2225篇 |
国内免费 | 2148篇 |
专业分类
电工技术 | 711篇 |
技术理论 | 2篇 |
综合类 | 8445篇 |
化学工业 | 3528篇 |
金属工艺 | 382篇 |
机械仪表 | 1605篇 |
建筑科学 | 3553篇 |
矿业工程 | 281篇 |
能源动力 | 145篇 |
轻工业 | 336篇 |
水利工程 | 257篇 |
石油天然气 | 129篇 |
武器工业 | 96篇 |
无线电 | 5258篇 |
一般工业技术 | 788篇 |
冶金工业 | 471篇 |
原子能技术 | 47篇 |
自动化技术 | 16567篇 |
出版年
2024年 | 72篇 |
2023年 | 330篇 |
2022年 | 736篇 |
2021年 | 1044篇 |
2020年 | 949篇 |
2019年 | 531篇 |
2018年 | 497篇 |
2017年 | 545篇 |
2016年 | 792篇 |
2015年 | 1249篇 |
2014年 | 3080篇 |
2013年 | 2103篇 |
2012年 | 3262篇 |
2011年 | 4054篇 |
2010年 | 3363篇 |
2009年 | 2870篇 |
2008年 | 2440篇 |
2007年 | 2713篇 |
2006年 | 2312篇 |
2005年 | 1918篇 |
2004年 | 1552篇 |
2003年 | 1468篇 |
2002年 | 1197篇 |
2001年 | 888篇 |
2000年 | 752篇 |
1999年 | 531篇 |
1998年 | 326篇 |
1997年 | 238篇 |
1996年 | 187篇 |
1995年 | 129篇 |
1994年 | 93篇 |
1993年 | 75篇 |
1992年 | 46篇 |
1991年 | 35篇 |
1990年 | 31篇 |
1989年 | 29篇 |
1988年 | 29篇 |
1987年 | 11篇 |
1986年 | 19篇 |
1985年 | 5篇 |
1984年 | 15篇 |
1983年 | 9篇 |
1982年 | 8篇 |
1972年 | 4篇 |
1966年 | 5篇 |
1962年 | 5篇 |
1959年 | 4篇 |
1957年 | 4篇 |
1956年 | 3篇 |
1955年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
1.
本文主要总结了新冠疫情期间作者的电磁场理论课程在线教学经验。对比分析了录播和直播的优缺点后,选择录播教学方式。基于超星网络教学平台,展示了录播网络教学的具体措施,包括网上答疑和学习效果检查以及在线批改作业等。给出了网络教学可以为线下教学继续使用的方法和手段,为疫情结束后的正常教学提供了新的网络教学补充措施。 相似文献
2.
Accurate and timely network traffic measurement is essential for network status monitoring, network fault analysis, network intrusion detection, and network security management. With the rapid development of the network, massive network traffic brings severe challenges to network traffic measurement. However, existing measurement methods suffer from many limitations for effectively recording and accurately analyzing big-volume traffic. Recently, sketches, a family of probabilistic data structures that employ hashing technology for summarizing traffic data, have been widely used to solve these problems. However, current literature still lacks a thorough review on sketch-based traffic measurement methods to offer a comprehensive insight on how to apply sketches for fulfilling various traffic measurement tasks. In this paper, we provide a detailed and comprehensive review on the applications of sketches in network traffic measurement. To this end, we classify the network traffic measurement tasks into four categories based on the target of traffic measurement, namely cardinality estimation, flow size estimation, change anomaly detection, and persistent spreader identification. First, we briefly introduce these four types of traffic measurement tasks and discuss the advantages of applying sketches. Then, we propose a series of requirements with regard to the applications of sketches in network traffic measurement. After that, we perform a fine-grained classification for each sketch-based measurement category according to the technologies applied on sketches. During the review, we evaluate the performance, advantages and disadvantages of current sketch-based traffic measurement methods based on the proposed requirements. Through the thorough review, we gain a number of valuable implications that can guide us to choose and design proper traffic measurement methods based on sketches. We also review a number of general sketches that are highly expected in modern network systems to simultaneously perform multiple traffic measurement tasks and discuss their performance based on the proposed requirements. Finally, through our serious review, we summarize a number of open issues and identify several promising research directions. 相似文献
3.
分析研究目前通信工程网络安全问题,提出几点解决问题的对策,旨在为提升通信工程网络安全性提供一定的帮助,以此来促使通信工程网络系统安全性的提升。 相似文献
4.
Zhenkun Ke Xin Cao Chuanli Shan Lifen Shi Pingping Wang Yong Yang Fengyang Zhao Jiedong Cui Jinwei Li Gang Zhou Min Guan Tao Yu 《Ceramics International》2021,47(14):19605-19613
The purpose of the current work was to research the effect of alkali metal oxide on the structure, thermal properties, viscosity and chemical stability in the glass system (R2O–CaO–B2O3–SiO2) systematically. Because the glass would emulsify when Li2O was added to the glass batch, this article did not discuss Li2O. The results showed that when the amount of Na2O was less than 4 mol.%, there was a higher interconnectivity of borate and silicate sub-networks in glass, as more mixed Si–O–B bonds were present in glass. The glass samples exhibited excellent thermal properties and chemical stabilities. As the amount of Na2O exceeded 4 mol.%, the interconnectivity of borate and silicate sub-networks was weakened. The thermal properties and chemical stabilities of the glass samples were reduced. The connectivity of the silicate sub-network was weakened slightly as the Na/K ratio varied, and the coefficient of thermal expansion (CTE) of the glass samples gradually increased, and the resistance to thermal shock (RTS) value gradually decreased. Moreover, the viscosity of the glass samples decreased with the ratio of Na/Si and Na/K increased. 相似文献
5.
Face aging (FA) for young faces refers to rendering the aging faces at target age for an individual, generally under 20s, which is an important topic of facial age analysis. Unlike traditional FA for adults, it is challenging to age children with one deep learning-based FA network, since there are deformations of facial shapes and variations of textural details. To alleviate the deficiency, a unified FA framework for young faces is proposed, which consists of two decoupled networks to apply aging image translation. It explicitly models transformations of geometry and appearance using two components: GD-GAN, which simulates the Geometric Deformation using Generative Adversarial Network; TV-GAN, which simulates the Textural Variations guided by the age-related saliency map. Extensive experiments demonstrate that our method has advantages over the state-of-the-art methods in terms of synthesizing visually plausible images for young faces, as well as preserving the personalized features. 相似文献
6.
7.
为了探讨在安卓平台上构建医用图像采集系统的开发个案,分析通过以智能手机、平板电脑为核心安卓设备通过拍照获得化验单数据后进行文本识别并提交智慧医疗系统的解决方案。本文首先通过二值化算法形成低阈值图像数据,使用卷积神经元网络算法对文本进行逐一识别,使用K-means算法对识别后的单字文本进行字段记录值的整合并形成元数据库服务于其他智慧医疗系统模块。在使用9000组数据对神经元网络进行前期训练的前提下,该系统的识别准确率达到了99.5%以上。本系统具有一定的可行性,对未来智慧医疗的系统开发有实践意义。 相似文献
8.
针对目前集成电路版图分析与设计课程存在教学方法老化、教学模式形式化等问题,本文以OBE-CDIO教育理念为指导,对”集成电路版图分析与设计”课程的课程教学模式、课程设计、项目式教学方式和课程考核方式等方面的改革进行有益的探索与实践。将工程教学认证中对学生的专业毕业要求作为制定教学目标的依据,将BB网络平台、ISO9001等现代化教学资源和质量标准融入课堂教学,采用OBE-CDIO能力教学理念指导课程设计,实现教学环节与考核环节的科学化与多元化,通过引入课程思政激发学生学习热情,树立社会主义核心价值观,全面地培养学生的综合版图分析与设计能力和素养。 相似文献
9.
10.
This paper analyzes the problems existing in the teaching of data structure course, and puts forward the reform from the as-
pects of strengthening basic programming, visualized explanation of abstract theory, combination of C++, Java programming, ratio-
nal use of online platform, and stratification of exercises, aiming at improving students' practical ability, learning interest and self-
confidence. 相似文献