全文获取类型
收费全文 | 6412篇 |
免费 | 344篇 |
国内免费 | 127篇 |
专业分类
电工技术 | 149篇 |
综合类 | 800篇 |
化学工业 | 454篇 |
金属工艺 | 1360篇 |
机械仪表 | 840篇 |
建筑科学 | 502篇 |
矿业工程 | 409篇 |
能源动力 | 26篇 |
轻工业 | 464篇 |
水利工程 | 69篇 |
石油天然气 | 58篇 |
武器工业 | 18篇 |
无线电 | 112篇 |
一般工业技术 | 489篇 |
冶金工业 | 471篇 |
原子能技术 | 7篇 |
自动化技术 | 655篇 |
出版年
2024年 | 3篇 |
2023年 | 24篇 |
2022年 | 57篇 |
2021年 | 80篇 |
2020年 | 73篇 |
2019年 | 43篇 |
2018年 | 63篇 |
2017年 | 105篇 |
2016年 | 96篇 |
2015年 | 123篇 |
2014年 | 295篇 |
2013年 | 238篇 |
2012年 | 424篇 |
2011年 | 396篇 |
2010年 | 346篇 |
2009年 | 340篇 |
2008年 | 281篇 |
2007年 | 474篇 |
2006年 | 425篇 |
2005年 | 417篇 |
2004年 | 381篇 |
2003年 | 337篇 |
2002年 | 326篇 |
2001年 | 302篇 |
2000年 | 284篇 |
1999年 | 203篇 |
1998年 | 122篇 |
1997年 | 122篇 |
1996年 | 117篇 |
1995年 | 109篇 |
1994年 | 74篇 |
1993年 | 52篇 |
1992年 | 41篇 |
1991年 | 32篇 |
1990年 | 13篇 |
1989年 | 17篇 |
1988年 | 13篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 7篇 |
1984年 | 7篇 |
1983年 | 1篇 |
1982年 | 8篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1964年 | 1篇 |
1957年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有6883条查询结果,搜索用时 15 毫秒
1.
为了解决传统教学无法全面培养人才的问题,采用"课程融合+时空耦合+过程结合"的方式开展人才培养研究。以注射模设计与制造生产过程为导向,构建大项目牵引下的跨越课程、跨越学期的课程融合新模式,利用信息通信技术及互联网平台,将互联网与传统教学进行深度融合,创造新的教学生态,构建多元多维互动的时空耦合教学新关系,以全方位评价为引导,构建课程多元多维的评价新机制。以3个班级为对象开展不同模式下的教学,对试验班级成绩进行分析,研究结果表明:课程融合+时空耦合+过程结合新模式培养的学生更好地完成了综合项目,获得了较好的教学效果。 相似文献
2.
Mg-Zn-Nd alloy is a promising biodegradable metal material for surgical staples during the reconstruc-tion of digestive tract due to its good biocompatibility and suitable mechanical properties.However,its deformation property and corrosion resistance should be improved to make better safety and effective-ness of staples.In the present study,bi-direction drawing was adopted to maintain the initial texture characteristics,and improve mechanical property and corrosion resistance of Mg-2Zn-0.5Nd alloy.The results showed that the microstructure after bi-direction did not change too much,but the texture could maintain its initial characteristics.The ductility of the alloy with 60 % accumulative area reduction after bi-direction drawing was increased by 70 %,indicating that an outstanding deformation property of Mg-Zn-Nd alloy can be obtained by bi-direction drawing.The corrosion resistance was also improved after bi-direction drawing compared with that under single direction drawing. 相似文献
3.
针对镍基高温合金因加工硬化严重成形时极易产生破裂和起皱等典型缺陷的问题,以锥筒形壳体类零件为对象,提出了一种由锥形预制坯经过真空固溶处理后拉深旋压成形锥筒形件的方法,并对其成形机理进行了研究。基于Abaqus/Explicit平台,建立了锥筒形件拉深旋压有限元模型,分析了成形过程中的瞬态等效应力、等效塑性应变、切向应力、壁厚及三向应变分布规律。结果表明:在旋压成形过程中,最大瞬态等效应力位于旋轮接触区及附近区域、最大瞬态等效塑性应变位于坯料口部;瞬态切向压应力最大值位于旋轮接触区,而瞬态切向拉应力最大值位于旋轮接触区附近的两侧区域。筒形段中部壁厚减薄,而坯料口部壁厚增厚。旋压成形试验表明,锥形预制坯经拉深旋压后可获得壁厚均匀的锥筒形件。 相似文献
4.
5.
Polymers beyond standard optical fibres – fabrication of microstructured polymer optical fibres 下载免费PDF全文
Eneko Arrospide Gaizka Durana Mikel Azkune Gotzon Aldabaldetreku Iñaki Bikandi Leire Ruiz‐Rubio Joseba Zubia 《Polymer International》2018,67(9):1155-1163
This paper reports the overall fabrication process of microstructured polymer optical fibres (mPOFs). mPOF fabrication involves a two‐step process: on the one hand, the design and creation of a preform containing a large‐scale version of the desired fibre and, on the other, the precise heating and drawing of the preform to the final fibre. The preforms are produced either by an improved drilling technique or by capillary stacking. For a correct and accurate drawing of the fibre, a controlled and precise heating unit has to be designed, an issue that will be explained in detail in this work. The quality and optical performance of the final mPOF depends strongly on key factors such as the preform annealing, the accuracy of the technique selected for the creation of the preform structure, the heating stage, as well as on the drawing parameters. All of them are analysed in detail and some drawn mPOFs of interest are reported as well. © 2018 Society of Chemical Industry 相似文献
6.
针对机械制图课程教学中普遍存在的教学模型及挂图数量不足、教学难度大等问题,简述了使用SolidWorks软件建立三维实体模型的过程以及机械制图虚拟模型库的设计流程、内容组成、网络发布等。实践证明,该模型库的设计是成功的,不仅弥补了实物模型库的不足,而且具有更多优势。 相似文献
7.
8.
9.
10.
Marc-Joseph Antonini Atharva Sahasrabudhe Anthony Tabet Miriam Schwalm Dekel Rosenfeld Indie Garwood Jimin Park Gabriel Loke Tural Khudiyev Mehmet Kanik Nathan Corbin Andres Canales Alan Jasanoff Yoel Fink Polina Anikeeva 《Advanced functional materials》2021,31(43):2104857
Fiber drawing enables scalable fabrication of multifunctional flexible fibers that integrate electrical, optical, and microfluidic modalities to record and modulate neural activity. Constraints on thermomechanical properties of materials, however, have prevented integrated drawing of metal electrodes with low-loss polymer waveguides for concurrent electrical recording and optical neuromodulation. Here, two fabrication approaches are introduced: 1) an iterative thermal drawing with a soft, low melting temperature (Tm) metal indium, and 2) a metal convergence drawing with traditionally non-drawable high Tm metal tungsten. Both approaches deliver multifunctional flexible neural interfaces with low-impedance metallic electrodes and low-loss waveguides, capable of recording optically-evoked and spontaneous neural activity in mice over several weeks. These fibers are coupled with a light-weight mechanical microdrive (1 g) that enables depth-specific interrogation of neural circuits in mice following chronic implantation. Finally, the compatibility of these fibers with magnetic resonance imaging is demonstrated and they are applied to visualize the delivery of chemical payloads through the integrated channels in real time. Together, these advances expand the domains of application of the fiber-based neural probes in neuroscience and neuroengineering. 相似文献