全文获取类型
收费全文 | 112740篇 |
免费 | 8065篇 |
国内免费 | 3158篇 |
专业分类
电工技术 | 4716篇 |
技术理论 | 4篇 |
综合类 | 4395篇 |
化学工业 | 18904篇 |
金属工艺 | 5405篇 |
机械仪表 | 6997篇 |
建筑科学 | 5723篇 |
矿业工程 | 1335篇 |
能源动力 | 3796篇 |
轻工业 | 8134篇 |
水利工程 | 1436篇 |
石油天然气 | 2795篇 |
武器工业 | 485篇 |
无线电 | 17183篇 |
一般工业技术 | 18348篇 |
冶金工业 | 8138篇 |
原子能技术 | 1397篇 |
自动化技术 | 14772篇 |
出版年
2024年 | 120篇 |
2023年 | 1287篇 |
2022年 | 1662篇 |
2021年 | 3473篇 |
2020年 | 2600篇 |
2019年 | 2416篇 |
2018年 | 2841篇 |
2017年 | 3009篇 |
2016年 | 3370篇 |
2015年 | 3632篇 |
2014年 | 4886篇 |
2013年 | 6993篇 |
2012年 | 6944篇 |
2011年 | 8063篇 |
2010年 | 6746篇 |
2009年 | 6641篇 |
2008年 | 6432篇 |
2007年 | 5734篇 |
2006年 | 5494篇 |
2005年 | 4738篇 |
2004年 | 3919篇 |
2003年 | 3681篇 |
2002年 | 3898篇 |
2001年 | 3164篇 |
2000年 | 2587篇 |
1999年 | 2363篇 |
1998年 | 3115篇 |
1997年 | 2217篇 |
1996年 | 1901篇 |
1995年 | 1637篇 |
1994年 | 1303篇 |
1993年 | 1116篇 |
1992年 | 808篇 |
1991年 | 747篇 |
1990年 | 609篇 |
1989年 | 552篇 |
1988年 | 446篇 |
1987年 | 348篇 |
1986年 | 313篇 |
1985年 | 268篇 |
1984年 | 232篇 |
1983年 | 170篇 |
1982年 | 173篇 |
1981年 | 149篇 |
1980年 | 147篇 |
1979年 | 111篇 |
1978年 | 96篇 |
1977年 | 123篇 |
1976年 | 169篇 |
1975年 | 87篇 |
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
2.
Journal of Materials Science - Three polyimides (PIs) were prepared from a diamine containing biphenyl ester group as a side chain and a corresponding dianhydride chosen from... 相似文献
3.
Anisse Pereira Hong C. Lee Robert Lammert Jr. Cailyn Wolberg Jr. Danyi Ma Chad Immoos Federico Casassa Iksoon Kang 《International Journal of Food Science & Technology》2022,57(3):1814-1823
This study was conducted to evaluate the effect of red-wine grape pomaces on the quality and sensory attributes of beef hamburger patties. Both phenolic content and antioxidant activity were assessed using Syrah, Merlot and Cabernet Sauvignon pomaces. Following the assessment, hamburger patties were prepared with Merlot pomace at 0%, 2% and 4% for the patty quality and sensory attributes. Grape seeds possessed significantly higher phenolics and antioxidant activities over the seedless pomace (P < 0.05), whereas no significant difference was found for phenolics and antioxidant activities within the seeds and seedless pomaces. The patty pH decreased as the pomace was added for 2% and 4%. Colour values (L*, a* and b*) of patties lowered as the pomace was added. Allo-Kramer shear force and hardness values increased while cooking yield decreased (P < 0.05) with the addition of pomace. No significant difference between control and Merlot patties was found for flavour, juiciness and colour, whereas lower sensory attributes were observed for texture, taste and overall acceptability. It is observed that the addition of fermented red-wine grape pomace provides hamburger patties with health promoting factors such as antioxidant and other functional components, but it also provided darker, sourer and lower cooking yield. 相似文献
4.
Liu Yang Pengfei Yu Wenyuan Li Fengliang Cao Xin Jin Sheng Xue Xianglong Zhang Tingwei Zhang Mingbo Wu Wenting Wu 《American Institute of Chemical Engineers》2022,68(9):e17760
Hydrogen peroxide (H2O2) has been listed as one of the 100 most important chemicals in the world. However, huge amount of residual H2O2 is hard to timely decomposed into O2 and H2O under acidic condition, easily resulting in explosion hazard. Here, we reported a core–shell structure catalyst, that is graphene with Co N structure encapsulated Co nanoparticles. Co N graphene shell serves as the active site for the H2O2 decomposition, and Co core further enhance this decomposition. Benefiting from it, the H2O2 decomposition were close to 100% after 6 cycles without pH adjustment, which increased 6 orders of magnitude compared with no catalyst. At the same time, the O2 generation reached 99.67% in 2 h with little metal leaching, and ·OH has been greatly inhibited to only 0.08%. This work can cleanly remove H2O2 with little deep oxidation and protect the process of H2O2 utilization to achieve a safer world. 相似文献
5.
6.
Jang Hye Ji Kim Jong Ha Lee Hyun-Sook Paik Hyun-Dong 《Food science and biotechnology》2022,31(6):731-737
Food Science and Biotechnology - The objective of this study was to develop a non-fermented probiotic milk that maintains its physicochemical properties, microbial properties, antioxidant activity,... 相似文献
7.
8.
9.
10.
Lee Jusang Chung Minyoung Lee Minkyung Shin Yeong-Gil 《Multimedia Tools and Applications》2022,81(13):18327-18342
Multimedia Tools and Applications - Individual tooth segmentation and identification from cone-beam computed tomography images are preoperative prerequisites for orthodontic treatments. Instance... 相似文献