全文获取类型
收费全文 | 22151篇 |
免费 | 1340篇 |
国内免费 | 56篇 |
专业分类
电工技术 | 311篇 |
综合类 | 27篇 |
化学工业 | 4886篇 |
金属工艺 | 887篇 |
机械仪表 | 1311篇 |
建筑科学 | 476篇 |
矿业工程 | 9篇 |
能源动力 | 884篇 |
轻工业 | 1898篇 |
水利工程 | 97篇 |
石油天然气 | 17篇 |
无线电 | 3668篇 |
一般工业技术 | 4753篇 |
冶金工业 | 1607篇 |
原子能技术 | 292篇 |
自动化技术 | 2424篇 |
出版年
2024年 | 11篇 |
2023年 | 267篇 |
2022年 | 308篇 |
2021年 | 695篇 |
2020年 | 480篇 |
2019年 | 513篇 |
2018年 | 710篇 |
2017年 | 669篇 |
2016年 | 782篇 |
2015年 | 616篇 |
2014年 | 952篇 |
2013年 | 1421篇 |
2012年 | 1486篇 |
2011年 | 1836篇 |
2010年 | 1330篇 |
2009年 | 1373篇 |
2008年 | 1255篇 |
2007年 | 973篇 |
2006年 | 844篇 |
2005年 | 726篇 |
2004年 | 653篇 |
2003年 | 606篇 |
2002年 | 605篇 |
2001年 | 523篇 |
2000年 | 447篇 |
1999年 | 432篇 |
1998年 | 714篇 |
1997年 | 431篇 |
1996年 | 403篇 |
1995年 | 260篇 |
1994年 | 169篇 |
1993年 | 156篇 |
1992年 | 113篇 |
1991年 | 101篇 |
1990年 | 80篇 |
1989年 | 90篇 |
1988年 | 75篇 |
1987年 | 64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 62 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.
4.
5.
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
6.
7.
Puneet Parmar Nicolas Lopez-Villalobos John T. Tobin Eoin Murphy Frank Buckley Shane V. Crowley Alan L. Kelly Laurence Shalloo 《International Journal of Food Science & Technology》2021,56(5):2415-2422
The objective of this study was to determine the effect of temperature on whole milk density measured at four different temperatures: 5, 10, 15, and 20 °C. A total of ninety-three individual milk samples were collected from morning milking of thirty-two Holstein Friesian dairy cows, of national average genetic merit, once every two weeks over a period of 4 weeks and were assessed by Fourier transform infrared spectroscopy for milk composition analysis. Density of the milk was evaluated using two different analytical methods: a portable density meter DMA35 and a standard desktop model DMA4500M (Anton Paar GmbH, UK). Milk density was analysed with a linear mixed model with the fixed effects of sampling period, temperature and analysis method; triple interaction of sampling period x analysis method x temperature; and the random effect of cow to account for repeated measures. The effect of temperature on milk density (ρ) was also evaluated including temperature (t) as covariate with linear and quadratic effects within each analytic method. The regression equation describing the curvature and density–temperature relationship for the DMA35 instrument was ρ = 1.0338−0.00017T−0.0000122T2 (R2 = 0.64), while it was ρ = 1.0334 + 0.000057T−0.00001T2 (R2 = 0.61) for DMA4500 instrument. The mean density determined with DMA4500 at 5 °C was 1.0334 g cm−3, with corresponding figures of 1.0330, 1.0320 and 1.0305 g cm−3 at 10, 15 and 20 °C, respectively. The milk density values obtained in this study at specific temperatures will help to address any bias in weight–volume calculations and thus may also improve the financial and operational control for the dairy processors in Ireland and internationally. 相似文献
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.