全文获取类型
收费全文 | 206866篇 |
免费 | 21436篇 |
国内免费 | 12362篇 |
专业分类
电工技术 | 16531篇 |
技术理论 | 7篇 |
综合类 | 16800篇 |
化学工业 | 29669篇 |
金属工艺 | 12455篇 |
机械仪表 | 13779篇 |
建筑科学 | 17106篇 |
矿业工程 | 6744篇 |
能源动力 | 6149篇 |
轻工业 | 15424篇 |
水利工程 | 4978篇 |
石油天然气 | 10699篇 |
武器工业 | 2380篇 |
无线电 | 25134篇 |
一般工业技术 | 21310篇 |
冶金工业 | 8442篇 |
原子能技术 | 2308篇 |
自动化技术 | 30749篇 |
出版年
2024年 | 1071篇 |
2023年 | 3522篇 |
2022年 | 6969篇 |
2021年 | 9501篇 |
2020年 | 7140篇 |
2019年 | 5481篇 |
2018年 | 6187篇 |
2017年 | 7208篇 |
2016年 | 6173篇 |
2015年 | 9169篇 |
2014年 | 11620篇 |
2013年 | 13617篇 |
2012年 | 15817篇 |
2011年 | 16580篇 |
2010年 | 15280篇 |
2009年 | 14101篇 |
2008年 | 14081篇 |
2007年 | 13211篇 |
2006年 | 12082篇 |
2005年 | 9611篇 |
2004年 | 6641篇 |
2003年 | 5618篇 |
2002年 | 5393篇 |
2001年 | 4751篇 |
2000年 | 3938篇 |
1999年 | 3456篇 |
1998年 | 2334篇 |
1997年 | 1883篇 |
1996年 | 1768篇 |
1995年 | 1495篇 |
1994年 | 1227篇 |
1993年 | 781篇 |
1992年 | 656篇 |
1991年 | 480篇 |
1990年 | 373篇 |
1989年 | 309篇 |
1988年 | 228篇 |
1987年 | 150篇 |
1986年 | 134篇 |
1985年 | 76篇 |
1984年 | 68篇 |
1983年 | 52篇 |
1982年 | 54篇 |
1981年 | 63篇 |
1980年 | 63篇 |
1979年 | 37篇 |
1978年 | 21篇 |
1977年 | 20篇 |
1976年 | 18篇 |
1951年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
Wei Shaowei Yu Guoxian Wang Jun Domeniconi Carlotta Zhang Xiangliang 《Machine Learning》2021,110(6):1505-1526
Machine Learning - Traditional clustering algorithms focus on a single clustering result; as such, they cannot explore potential diverse patterns of complex real world data. To deal with this... 相似文献
22.
With the emergence of large-scale knowledge base, how to use triple information to generate natural questions is a key technology in question answering systems. The traditional way of generating questions require a lot of manual intervention and produce lots of noise. To solve these problems, we propose a joint model based on semi-automated model and End-to-End neural network to automatically generate questions. The semi-automated model can generate question templates and real questions combining the knowledge base and center graph. The End-to-End neural network directly sends the knowledge base and real questions to BiLSTM network. Meanwhile, the attention mechanism is utilized in the decoding layer, which makes the triples and generated questions more relevant. Finally, the experimental results on SimpleQuestions demonstrate the effectiveness of the proposed approach. 相似文献
23.
Malondialdehyde (MDA) was selected to represent a secondary by-product of lipid peroxidation during rice ageing. This study aimed to investigate the effects of MDA modification on the structural characteristics of rice protein. The results showed that as MDA concentration increased, rice protein carbonyl and disulphide groups increased, but sulphydryl content decreased. The blue shift of maximum fluorescence peak, the decrease of rice protein intrinsic fluorescence intensity and the reduction of surface hydrophobicity indicated the formation of protein aggregates caused by MDA oxidative modification. The results of molecular weight distribution and particle size distribution showed that MDA modification resulted in the formation of soluble protein aggregates, and the decrease of rice protein solubility indicated that insoluble protein aggregates were formed. Results of protein electrophoresis showed that MDA modification contributed to rice protein aggregation via non-disulphide covalent bonds. The results showed that rice protein gradually aggregated with increasing MDA concentration. 相似文献
24.
Yan Jing Zhu Rongying Wu Fan Zhao Ziyin Ye Huan Hou Mengying Liu Yong Yin Lichen 《Nano Research》2020,13(10):2706-2715
Nano Research - Insufficient intratumoral penetration greatly hurdles the anticancer performance of nanomedicine. To realize highly efficient tumor penetration in a precisely and spatiotemporally... 相似文献
25.
文章主要研究用水浸法提取落葵浆果天然染料及研究浸提液对羊毛织物的染色性能。以水为提取剂提取落葵浆果天然染料,探讨提取工艺中料液比、提取温度及时间等因素对落葵浆果天然染料提取效果的影响。研究结果表明,落葵浆果水浸提法优化工艺为:料液比1∶20、提取温度70℃、提取时间30 min。落葵浆果天然染料可以对羊毛织物进行染色,媒染染色与直接染色相比,染色深度深且会呈现不同的颜色。由于媒染剂的络合作用,媒染染色色牢度比直接染色普遍高1~2级。 相似文献
26.
27.
28.
针对基站柜式空调耗电量大的问题,创造性地使用基站分布式冷却的方式,达到精确送风,节能高效的目的.在应用实践中检验了分布式冷却系统实际节能量和应用效果,总结出分布式冷却系统应用场景和范围,为更大范围推广应用DCS分布式冷却系统提供实践依据. 相似文献
29.
The fracture behaviour and morphologies of high-strength boron steel were investigated at different temperatures at a constant strain rate of 0.1 s-1 based on isothermal tensile tests. Fracture mechanisms were also analyzed based on the relationship between microstructure transformation and continuous cooling transformation(CCT) curves. It is found that 1) fractures of the investigated steel at high temperatures are dimple fractures; 2) the deformation of high-strength boron steel at high temperatures accelerates diffusion transformations; thus, to obtain full martensite, a higher cooling rate is needed; and 3) the investigated steel has the best plasticity when the deformation temperature is 750 °C. 相似文献
30.
A contact layer element for large deformations 总被引:1,自引:0,他引:1