全文获取类型
收费全文 | 59890篇 |
免费 | 5386篇 |
国内免费 | 3074篇 |
专业分类
电工技术 | 3921篇 |
技术理论 | 4篇 |
综合类 | 4322篇 |
化学工业 | 9797篇 |
金属工艺 | 3375篇 |
机械仪表 | 3951篇 |
建筑科学 | 4530篇 |
矿业工程 | 1313篇 |
能源动力 | 1699篇 |
轻工业 | 4378篇 |
水利工程 | 1189篇 |
石油天然气 | 2646篇 |
武器工业 | 484篇 |
无线电 | 7643篇 |
一般工业技术 | 7773篇 |
冶金工业 | 2423篇 |
原子能技术 | 761篇 |
自动化技术 | 8141篇 |
出版年
2024年 | 240篇 |
2023年 | 878篇 |
2022年 | 1680篇 |
2021年 | 2365篇 |
2020年 | 1708篇 |
2019年 | 1532篇 |
2018年 | 1628篇 |
2017年 | 1832篇 |
2016年 | 1841篇 |
2015年 | 2477篇 |
2014年 | 2979篇 |
2013年 | 3634篇 |
2012年 | 3895篇 |
2011年 | 4301篇 |
2010年 | 3884篇 |
2009年 | 3543篇 |
2008年 | 3572篇 |
2007年 | 3303篇 |
2006年 | 3283篇 |
2005年 | 2837篇 |
2004年 | 2093篇 |
2003年 | 1996篇 |
2002年 | 2270篇 |
2001年 | 1893篇 |
2000年 | 1519篇 |
1999年 | 1319篇 |
1998年 | 1061篇 |
1997年 | 882篇 |
1996年 | 799篇 |
1995年 | 699篇 |
1994年 | 590篇 |
1993年 | 447篇 |
1992年 | 327篇 |
1991年 | 260篇 |
1990年 | 189篇 |
1989年 | 151篇 |
1988年 | 129篇 |
1987年 | 75篇 |
1986年 | 58篇 |
1985年 | 41篇 |
1984年 | 31篇 |
1983年 | 16篇 |
1982年 | 23篇 |
1981年 | 21篇 |
1980年 | 16篇 |
1979年 | 8篇 |
1976年 | 8篇 |
1975年 | 7篇 |
1959年 | 4篇 |
1951年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
101.
Monitoring the Dynamic Process of Formation of Plasmonic Molecular Junctions during Single Nanoparticle Collisions 下载免费PDF全文
Jing Guo Jie Pan Shuai Chang Xuewen Wang Na Kong Wenrong Yang Jin He 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(15)
The capability to study the dynamic formation of plasmonic molecular junction is of fundamental importance, and it will provide new insights into molecular electronics/plasmonics, single‐entity electrochemistry, and nanooptoelectronics. Here, a facile method to form plasmonic molecular junctions is reported by utilizing single gold nanoparticle (NP) collision events at a highly curved gold nanoelectrode modified with a self‐assembled monolayer. By using time‐resolved electrochemical current measurement and surface‐enhanced Raman scattering spectroscopy, the current changes and the evolution of interfacial chemical bonding are successfully observed in the newly formed molecular tunnel junctions during and after the gold NP “hit‐n‐stay” and “hit‐n‐run” collision events. The results lead to an in‐depth understanding of the single NP motion and the associated molecular level changes during the formation of the plasmonic molecular junctions in a single NP collision event. This method also provides a new platform to study molecular changes at the single molecule level during electron transport in a dynamic molecular tunnel junction. 相似文献
102.
103.
本文从实际应用出发,详尽论述了“智能耳诊机”软、硬件设计的方法。对从事单片机开发应用的工程技术人员有较高的参考价值。 相似文献
104.
High quality single crystals of YBa2Cu3O7- (YBCO) have been grown in yttria-stabilized zirconia crucibles by using a flux method. This method yields crystals with area 3 to 4 times larger than a previous method, and 3 to 5 times more crystals. Several crystals as large as 3×4mm2 in thea-b plane are routinely obtained from each crucible. The samples typically range from 10 to 60 m thick. The superconductivity transition temperatureT
c
of the crystals, measured by magnetic susceptibility, falls in the range 92.5 to 93 K and the smallest transition width (10 to 90%) is less than 0.25 K. Compared with the previous method, the surface is generally smoother, with less flux, and larger untwinned regions of 1 x 1 mm2 are usually found. 相似文献
105.
106.
107.
This article proposes an asymmetric topology for transmit/receive (T/R) switches and more importantly presents a comparative study of both LC‐tuned and resistive body‐floating techniques for improving the power‐handling capability of the T/R switches in the same 0.18‐μm triple‐well CMOS. It is shown from simulations and measurements that the switches adopting either technique achieve comparable performances. For instance, the switch employing the LC‐tuned body‐floating technique exhibits insertion loss of 1.5 dB, isolation of 23.5 dB, and power‐handling capability of 22.5 dBm at 5.2 GHz, whereas the switch using the resistive body‐floating technique exhibits insertion loss of 1.3 dB, isolation of 24 dB, and power‐handling capability of 22.2 dBm, respectively. Therefore, one can conclude that the asymmetric topology with the resistive body‐floating technique is more suitable for designing T/R switches for wireless local area network applications as it consumes smaller silicon area. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. 相似文献
108.
109.
110.