全文获取类型
收费全文 | 1517篇 |
免费 | 101篇 |
国内免费 | 57篇 |
专业分类
电工技术 | 117篇 |
技术理论 | 1篇 |
综合类 | 83篇 |
化学工业 | 252篇 |
金属工艺 | 55篇 |
机械仪表 | 112篇 |
建筑科学 | 78篇 |
矿业工程 | 39篇 |
能源动力 | 26篇 |
轻工业 | 206篇 |
水利工程 | 14篇 |
石油天然气 | 142篇 |
武器工业 | 34篇 |
无线电 | 149篇 |
一般工业技术 | 121篇 |
冶金工业 | 68篇 |
原子能技术 | 30篇 |
自动化技术 | 148篇 |
出版年
2024年 | 2篇 |
2023年 | 20篇 |
2022年 | 61篇 |
2021年 | 76篇 |
2020年 | 48篇 |
2019年 | 45篇 |
2018年 | 45篇 |
2017年 | 41篇 |
2016年 | 29篇 |
2015年 | 59篇 |
2014年 | 47篇 |
2013年 | 86篇 |
2012年 | 102篇 |
2011年 | 89篇 |
2010年 | 99篇 |
2009年 | 72篇 |
2008年 | 102篇 |
2007年 | 81篇 |
2006年 | 100篇 |
2005年 | 57篇 |
2004年 | 44篇 |
2003年 | 37篇 |
2002年 | 32篇 |
2001年 | 35篇 |
2000年 | 42篇 |
1999年 | 46篇 |
1998年 | 42篇 |
1997年 | 28篇 |
1996年 | 20篇 |
1995年 | 28篇 |
1994年 | 14篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1981年 | 2篇 |
1980年 | 4篇 |
排序方式: 共有1675条查询结果,搜索用时 15 毫秒
1.
Sumeng Wei Yining Xu Baohua Kong Meijuan Wang Jingming Zhang Qian Liu Yuling Yang 《International Journal of Food Science & Technology》2022,57(8):5024-5035
The present work was conducted to illustrate the mechanism of gel formation of myofibrillar proteins (MPs) under different microwave heating times. The results showed that the denaturation enthalpy (ΔH) of the MPs significantly decreased when the heating time increased from 3 to 9 s and then completely disappeared as the heating time progressed, indicating that the MPs gradually denatured and subsequently aggregated with increasing heating time, which was further verified by the changes in the secondary structure, electrophoretic bands, and gel properties (e.g., water holding capacity and textural profiles) of the MPs. Microstructural images indicated that the MP gel formed under 12 s had the most compact network, indicating that extended microwave heating time could induce quality deterioration of MP gels. Moreover, the hydrophobic forces, electrostatic forces, and disulphide bonds of the MPs gradually intensified with increasing microwave heating time, suggesting that both non-covalent and covalent bonds could promote molecular denaturation and subsequent aggregation of MPs. In addition, correlation analysis revealed that the changes in the molecular conformation of MPs induced by different microwave heating times could effectively regulate the formation of MP gels and their related properties. 相似文献
2.
Guangbo Zeng Dongqing Zhang Liuming Yan Baohua Yue Ting Pan Yidong Hu Shufa He Hongbin Zhao Jiujun Zhang 《International Journal of Hydrogen Energy》2021,46(39):20664-20677
Side-chain optimized poly (2,6-dimethyl-1,4-phenylene oxide)-g-poly (styrene sulfonic acid) (PPO-g-PSSA) is designed with balanced water-resistance and sulfonation degree. The PPO-g-PSSA is synthesized by controlled atom-transfer radical polymerization (ATRP) from brominated poly (2,6-dimethyl-1,4-phenylene oxide) (PPO-xBr) and ethyl styrene-4-sulfonate and followed by hydrolysis. A series of PPO-g-PSSA are prepared possessing different bromination degree (x) of PPO-xBr and polymerization degree (m) of the side-chains and the water-resistances of the fabricated membranes are investigated. The results show that a PPO-g-PSSA at relatively low x (x < 0.2) and high m (m > 4) exhibits good balance between the water-resistance and the sulfonation degree. Namely, it displays suitable proton conductivity with compromised water-resistance. Moreover, a maximum ion exchange capacity (IEC) of 3.24 mmol g?1 is reached without the sacrifice of water-resistance. In addition, PPO-g-0.08PSSA-13 and PPO-g-0.14PSSA-4 are chosen characterized by thermogravimetric analysis, proton conductivities and mechanical properties. At 90% RH, the optimized PPO-g-0.08PPSA-13 possesses a proton conductivity of 37.9 mS cm?1 at 40 °C and 45.5 mS cm?1 at 95 °C, respectively. 相似文献
3.
4.
5.
针对加油站在油品进、销、存方面因管理和人为作弊而产生的损耗大问题,提出了解决办法:各环节交接手续要严密完备;发货方实施保量运输,选择信誉好的承运方;在销售、储存方面应加强管理,推行加油站计量员、账务员集中管理,主要账表电子表格化,及时上报主管部门,执行责任追究制并与效益工资挂钩。 相似文献
6.
本文介绍了大型牵伸卷绕机的计算机控制系统,以西门子MMV型变频器为驱动装置,西门子PLC300为控制核心,根据西门子USS协议和MPI协议,实现PLC与变频器、TP27触摸显示屏的通信,取得了较高的控制精度和稳定性,充分满足生产过程的需要,具有广阔的应用前景。 相似文献
7.
8.
9.
Yewang Su Baohua Ji Yonggang Huang Kehchih Hwang 《Journal of Materials Science》2007,42(21):8885-8893
Wet adhesion is widely adopted in biological adhesion systems in nature. Wet adhesion is studied in this paper with the focus
on the effect of different contact shapes (flat, concave, convex, and ring-like) on the adhesion force. The evolution of the
liquid bridge between a fiber tip and substrate during the detaching process shows two transition points. The first transition
from the radius-controlled to the contact-angle controlled process is critical to influence the strength and robustness of
adhesion. We show that a concave shape is more effective than a flat one, while a convex shape has no advantage. A ring-like
contact shape has advantages in a hydrophobic environment and on a rough surface. 相似文献
10.