全文获取类型
收费全文 | 31679篇 |
免费 | 2096篇 |
国内免费 | 70篇 |
专业分类
电工技术 | 470篇 |
综合类 | 35篇 |
化学工业 | 7336篇 |
金属工艺 | 1272篇 |
机械仪表 | 1842篇 |
建筑科学 | 580篇 |
矿业工程 | 11篇 |
能源动力 | 1248篇 |
轻工业 | 2630篇 |
水利工程 | 129篇 |
石油天然气 | 22篇 |
武器工业 | 1篇 |
无线电 | 5298篇 |
一般工业技术 | 6902篇 |
冶金工业 | 2285篇 |
原子能技术 | 396篇 |
自动化技术 | 3388篇 |
出版年
2024年 | 31篇 |
2023年 | 393篇 |
2022年 | 576篇 |
2021年 | 980篇 |
2020年 | 696篇 |
2019年 | 741篇 |
2018年 | 983篇 |
2017年 | 1016篇 |
2016年 | 1176篇 |
2015年 | 939篇 |
2014年 | 1429篇 |
2013年 | 2065篇 |
2012年 | 2156篇 |
2011年 | 2655篇 |
2010年 | 1903篇 |
2009年 | 1931篇 |
2008年 | 1709篇 |
2007年 | 1359篇 |
2006年 | 1189篇 |
2005年 | 999篇 |
2004年 | 950篇 |
2003年 | 876篇 |
2002年 | 805篇 |
2001年 | 700篇 |
2000年 | 631篇 |
1999年 | 599篇 |
1998年 | 986篇 |
1997年 | 603篇 |
1996年 | 543篇 |
1995年 | 343篇 |
1994年 | 264篇 |
1993年 | 234篇 |
1992年 | 179篇 |
1991年 | 152篇 |
1990年 | 117篇 |
1989年 | 121篇 |
1988年 | 104篇 |
1987年 | 79篇 |
1986年 | 75篇 |
1985年 | 76篇 |
1984年 | 57篇 |
1983年 | 42篇 |
1982年 | 40篇 |
1981年 | 39篇 |
1980年 | 48篇 |
1979年 | 29篇 |
1977年 | 34篇 |
1976年 | 50篇 |
1975年 | 25篇 |
1974年 | 28篇 |
排序方式: 共有10000条查询结果,搜索用时 20 毫秒
1.
2.
Hong Sae Jin Park Nam Il Hwang Dae Keun Yi Tae Gyu Eum Hyang Lan 《Food science and biotechnology》2022,31(6):669-679
Food Science and Biotechnology - Various hilling materials (rice hulls, pine sawdust, and perlite) were compared to produce sprout vegetables using beach silvertop (Glehnia littoralis Fr. Schm. ex... 相似文献
3.
International Journal of Information Security - Machine learning techniques have been widely used and shown remarkable performance in various fields. Along with the widespread utilization of... 相似文献
4.
5.
Young Been Kim Sung Hyeon Jung Dong Su Kim Nishad G. Deshpande Hee Won Suh Hak Hyeon Lee Ji Hoon Choi Ho Seong Lee Hyung Koun Cho 《Advanced functional materials》2021,31(38):2102439
Antimony triselenide (Sb2Se3) nanoflake-based nitrogen dioxide (NO2) sensors exhibit a progressive bifunctional gas-sensing performance, with a rapid alarm for hazardous highly concentrated gases, and an advanced memory-type function for low-concentration (<1 ppm) monitoring repeated under potentially fatal exposure. Rectangular and cuboid shaped Sb2Se3 nanoflakes, comprising van der Waals planes with large surface areas and covalent bond planes with small areas, can rapidly detect a wide range of NO2 gas concentrations from 0.1 to 100 ppm. These Sb2Se3 nanoflakes are found to be suitable for physisorption-based gas sensing owing to their anisotropic quasi-2D crystal structure with extremely enlarged van der Waals planes, where they are humidity-insensitive and consequently exhibit an extremely stable baseline current. The Sb2Se3 nanoflake sensor exhibits a room-temperature/low-voltage operation, which is noticeable owing to its low energy consumption and rapid response even under a NO2 gas flow of only 1 ppm. As a result, the Sb2Se3 nanoflake sensor is suitable for the development of a rapid alarm system. Furthermore, the persistent gas-sensing conductivity of the sensor with a slow decaying current can enable the development of a progressive memory-type sensor that retains the previous signal under irregular gas injection at low concentrations. 相似文献
6.
Wireless Personal Communications - Random Access techniques are many, most of which are designed for a limited number of mobile nodes. However, in a 5G Internet of Things environment, the design of... 相似文献
7.
8.
Food Science and Biotechnology - Aluminum based reflective nanolens arrays were developed via a series of aluminum electropolishing and anodization steps with subsequent selective dissolution of... 相似文献
9.
10.
Eui Dae Jung Amit Kumar Harit Do Hui Kim Chung Hyeon Jang Jong Hyun Park Shinuk Cho Myoung Hoon Song Han Young Woo 《Advanced materials (Deerfield Beach, Fla.)》2020,32(30):2002333
A series of anionic conjugated polyelectrolytes (CPEs) is synthesized based on poly(fluorene-co-phenylene) by varying the side-chain ionic density from two to six per repeat units (MPS2-TMA, MPS4-TMA, and MPS6-TMA). The effect of MPS2, 4, 6-TMA as interlayers on top of a hole-extraction layer of poly(bis(4-phenyl)-2,4,6-trimethylphenylamine (PTAA) is investigated in inverted perovskite solar cells (PeSCs). Owing to the improved wettability of perovskites on hydrophobic PTAA with the CPEs, the PeSCs with CPE interlayers demonstrate a significantly enhanced device performance, with negligible device-to-device dependence relative to the reference PeSC without CPEs. By increasing the ionic density in the MPS-TMA interlayers, the wetting, interfacial defect passivation, and crystal growth of the perovskites are significantly improved without increasing the series resistance of the PeSCs. In particular, the open-circuit voltage increases from 1.06 V for the PeSC with MPS2-TMA to 1.11 V for the PeSC with MPS6-TMA. The trap densities of the PeSCs with MPS2,4,6-TMA are further analyzed using frequency-dependent capacitance measurements. Finally, a large-area (1 cm2) PeSC is successfully fabricated with MPS6-TMA, showing a power conversion efficiency of 18.38% with negligible hysteresis and a stable power output under light soaking for 60 s. 相似文献