全文获取类型
收费全文 | 21914篇 |
免费 | 1336篇 |
国内免费 | 60篇 |
专业分类
电工技术 | 315篇 |
综合类 | 27篇 |
化学工业 | 4924篇 |
金属工艺 | 883篇 |
机械仪表 | 1299篇 |
建筑科学 | 428篇 |
矿业工程 | 7篇 |
能源动力 | 866篇 |
轻工业 | 1864篇 |
水利工程 | 103篇 |
石油天然气 | 16篇 |
无线电 | 3674篇 |
一般工业技术 | 4661篇 |
冶金工业 | 1557篇 |
原子能技术 | 292篇 |
自动化技术 | 2394篇 |
出版年
2024年 | 24篇 |
2023年 | 281篇 |
2022年 | 406篇 |
2021年 | 696篇 |
2020年 | 484篇 |
2019年 | 511篇 |
2018年 | 708篇 |
2017年 | 673篇 |
2016年 | 783篇 |
2015年 | 611篇 |
2014年 | 945篇 |
2013年 | 1410篇 |
2012年 | 1465篇 |
2011年 | 1791篇 |
2010年 | 1302篇 |
2009年 | 1344篇 |
2008年 | 1219篇 |
2007年 | 941篇 |
2006年 | 814篇 |
2005年 | 709篇 |
2004年 | 640篇 |
2003年 | 586篇 |
2002年 | 595篇 |
2001年 | 517篇 |
2000年 | 437篇 |
1999年 | 423篇 |
1998年 | 711篇 |
1997年 | 422篇 |
1996年 | 395篇 |
1995年 | 257篇 |
1994年 | 169篇 |
1993年 | 151篇 |
1992年 | 112篇 |
1991年 | 100篇 |
1990年 | 75篇 |
1989年 | 88篇 |
1988年 | 74篇 |
1987年 | 63篇 |
1986年 | 51篇 |
1985年 | 43篇 |
1984年 | 36篇 |
1983年 | 28篇 |
1982年 | 31篇 |
1981年 | 26篇 |
1980年 | 29篇 |
1979年 | 13篇 |
1977年 | 22篇 |
1976年 | 33篇 |
1975年 | 17篇 |
1974年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
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
2.
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
3.
Darothi Bairagi Venkataramana Munukuti Pallabi Bhuyan Rajib Saha Sumantra Mandal 《工业材料与腐蚀》2021,72(5):829-838
The influence of cementite spheroidization on the impact toughness and electrochemical properties of a high-carbon steel has been thoroughly investigated in this study. Heavy warm rolling, followed by 2 h of annealing, has resulted in near-complete spheroidization, leading to a microstructure consisting of nano-cementite globules dispersed in the ultrafine-grained ferritic matrix. The Charpy impact test exhibited superior impact toughness with increased spheroidization. It is validated by the presence of abundant dimples in the fractographs of spheroidized specimens, in contrast to the as-received one that experienced a brittle failure due to its lamellar pearlitic structure. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) carried out in a 3.5% NaCl solution revealed that the corrosion resistance of the alloy gets improved with the increase in the degree of spheroidization. This is attributed to the lower susceptibility of the spheroidized specimen to microgalvanic corrosion owing to the minimum area of contact between nano-spheroidized cementite and ferrite, as elucidated with the help of EIS results aided by equivalent electrical circuit model. 相似文献
4.
5.
6.
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
7.
8.
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
9.
10.