全文获取类型
收费全文 | 32564篇 |
免费 | 1625篇 |
国内免费 | 686篇 |
专业分类
电工技术 | 694篇 |
综合类 | 8634篇 |
化学工业 | 3649篇 |
金属工艺 | 862篇 |
机械仪表 | 1380篇 |
建筑科学 | 5404篇 |
矿业工程 | 817篇 |
能源动力 | 199篇 |
轻工业 | 494篇 |
水利工程 | 863篇 |
石油天然气 | 592篇 |
武器工业 | 100篇 |
无线电 | 3231篇 |
一般工业技术 | 924篇 |
冶金工业 | 742篇 |
原子能技术 | 369篇 |
自动化技术 | 5921篇 |
出版年
2024年 | 111篇 |
2023年 | 277篇 |
2022年 | 579篇 |
2021年 | 728篇 |
2020年 | 778篇 |
2019年 | 440篇 |
2018年 | 337篇 |
2017年 | 491篇 |
2016年 | 765篇 |
2015年 | 1118篇 |
2014年 | 2771篇 |
2013年 | 1776篇 |
2012年 | 2920篇 |
2011年 | 3331篇 |
2010年 | 2976篇 |
2009年 | 2612篇 |
2008年 | 1925篇 |
2007年 | 2133篇 |
2006年 | 1713篇 |
2005年 | 1289篇 |
2004年 | 1095篇 |
2003年 | 984篇 |
2002年 | 854篇 |
2001年 | 710篇 |
2000年 | 603篇 |
1999年 | 385篇 |
1998年 | 207篇 |
1997年 | 192篇 |
1996年 | 148篇 |
1995年 | 158篇 |
1994年 | 95篇 |
1993年 | 57篇 |
1992年 | 55篇 |
1991年 | 47篇 |
1990年 | 31篇 |
1989年 | 42篇 |
1988年 | 30篇 |
1987年 | 11篇 |
1986年 | 8篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1967年 | 4篇 |
1966年 | 5篇 |
1962年 | 5篇 |
1959年 | 6篇 |
1957年 | 4篇 |
1955年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 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.
Atsuki Yamaguchi Kazuki Fukui Yuki Fujiwara Shingo Tamaki Sachie Kusaka Fuminobu Sato 《Journal of Nuclear Science and Technology》2021,58(1):80-86
ABSTRACT It is important to perform neutron transport simulations with accurate nuclear data in the neutronics design of a fusion reactor. However, absolute values of large-angle scattering cross sections vary among nuclear data libraries even for well-examined nuclide of iron. Benchmark experiments focusing on large-angle scattering cross sections were thus performed to confirm the correctness of nuclear data libraries. The series benchmark experiments were performed at a DT neutron source facility, OKTAVIAN of Osaka University, Japan, by the unique experimental system established by the authors’ group, which can extract only the contribution of large-angle scattering reactions. This system consists of two shadow bars, target plate (iron), and neutron detector (niobium). Two types of shadow bars were used and four irradiations were conducted for one experiment, so that contribution of room-return neutrons was effectively removed and only large-angle scattering neutrons were extracted from the measured four Nb reaction rates. The obtained experimental results were compared with calculations for five nuclear data libraries including JENDL-4.0, JEFF.-3.3, FENDL-3.1, ENDF/B- VII, and recently released ENDF/B-VIII. It was found from the comparison that ENDF/B-VIII showed the best result, though ENDF/B-VII showed overestimation and others are in large underestimation at 14 MeV. 相似文献
3.
4.
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
5.
《International Journal of Hydrogen Energy》2022,47(19):10747-10761
To obtain the mixing enhancement mechanism of H2–Water combined jets in supersonic crossflows in a combustor with expanded section for rotating detonation ramjet, the flow field shape and spray structure were studied by experimental and numerical methods. The Eulerian–Lagrangian method was used to investigate the diffusion mechanism and H2–Water interaction law of combined jets with different sequences. At the same time, high-speed photography and the schlieren technique were used to capture the flow field. The effects of jet pressure drop, orifice diameter, orifice spacing, incoming Mach number, and other parameters on the penetration depth of water jets were studied. The results of experiment and simulation show that using H2–Water combined jets, the penetration depth of the jet spray can be greatly increased and the jet mixing effect can be significantly improved, which will contribute to the engine's ignition and stable combustion. In the case of pre-water/post-H2, the penetration depth of the hydrogen jet is greater. In the case of pre-H2/post-water, the hydrogen jet raises the water spray mainly by protecting the integrity of the water column. 相似文献
6.
7.
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
8.
张皓博 《重庆电力高等专科学校学报》2015,(3):5-6,17
以可编程控制器课程为例,介绍"任务驱动"教学法在教学过程中的具体应用,并探讨了实施过程中存在的问题与解决方法。 相似文献
9.
Rectangular section control technology(RSCT)was introduced to achieve high-precision profile control during silicon steel rolling.The RSCT principle and method were designed,and the whole RSCT control strategy was developed.Specifically,RSCT included roll contour design,rolling technology optimization,and control strategy development,aiming at both hot strip mills(HSMs)and cold strip mills(CSMs).Firstly,through the high-performance variable crown(HVC)work roll optimization design in the upper-stream stands and the limited shifting technology for schedule-free rolling in the downstream stands of HSMs,a hot strip with a stable crown and limited wedge,local spot,and single wave was obtained,which was suitable for cold rolling.Secondly,an approximately rectangular section was obtained by edge varying contact(EVC)work roll contour design,edge-drop setting control,and closed loop control in the upper-stream stands of CSMs.Moreover,complex-mode flatness control was realized by coordinating multiple shape-control methods in the downstream stands of CSMs.In addition,the RSCT approach was applied in several silicon-steel production plants,where an outstanding performance and remarkable economic benefits were observed. 相似文献
10.
Georgios Tsaparlis 《Israel journal of chemistry》2019,59(6-7):478-492
Numerous conceptual difficulties and misconceptions have been reported in the science and chemistry education literature about electrochemistry concepts such as electrolytes, redox equations, and about electrochemical (galvanic and electrolytic) cells. Other studies have considered teaching approaches aimed at improving learning and at overcoming misconceptions. This paper reviews these studies and considers strategies and approaches for the effective teaching of electrochemistry. Then, the review focuses on problem solving in equilibrium electrochemistry, especially problems involving the Nernst equation. The main findings of four studies with Greek university chemistry students, dealing with: (i) algorithmic problem‐solving ability; (ii) practice on problem solving; (iii) the effect of the format of a problem; and (iv) the construction and evaluation of a website devoted to electrochemistry problem solving, are reported. 相似文献