全文获取类型
收费全文 | 223516篇 |
免费 | 24723篇 |
国内免费 | 14291篇 |
专业分类
电工技术 | 18707篇 |
技术理论 | 7篇 |
综合类 | 19103篇 |
化学工业 | 31708篇 |
金属工艺 | 13580篇 |
机械仪表 | 15070篇 |
建筑科学 | 18849篇 |
矿业工程 | 7456篇 |
能源动力 | 6741篇 |
轻工业 | 18701篇 |
水利工程 | 5580篇 |
石油天然气 | 10679篇 |
武器工业 | 2687篇 |
无线电 | 27053篇 |
一般工业技术 | 22147篇 |
冶金工业 | 8641篇 |
原子能技术 | 2449篇 |
自动化技术 | 33372篇 |
出版年
2024年 | 1272篇 |
2023年 | 4093篇 |
2022年 | 8218篇 |
2021年 | 10975篇 |
2020年 | 8073篇 |
2019年 | 6230篇 |
2018年 | 6843篇 |
2017年 | 7959篇 |
2016年 | 6883篇 |
2015年 | 10369篇 |
2014年 | 12837篇 |
2013年 | 14844篇 |
2012年 | 17592篇 |
2011年 | 18240篇 |
2010年 | 16599篇 |
2009年 | 15755篇 |
2008年 | 15408篇 |
2007年 | 14436篇 |
2006年 | 12977篇 |
2005年 | 10261篇 |
2004年 | 7265篇 |
2003年 | 6273篇 |
2002年 | 6229篇 |
2001年 | 5386篇 |
2000年 | 4087篇 |
1999年 | 3159篇 |
1998年 | 1950篇 |
1997年 | 1615篇 |
1996年 | 1454篇 |
1995年 | 1254篇 |
1994年 | 1019篇 |
1993年 | 659篇 |
1992年 | 519篇 |
1991年 | 373篇 |
1990年 | 300篇 |
1989年 | 245篇 |
1988年 | 181篇 |
1987年 | 126篇 |
1986年 | 115篇 |
1985年 | 49篇 |
1984年 | 43篇 |
1983年 | 29篇 |
1982年 | 49篇 |
1981年 | 49篇 |
1980年 | 58篇 |
1979年 | 33篇 |
1978年 | 10篇 |
1976年 | 10篇 |
1959年 | 12篇 |
1951年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Wei LingNan Wang ZhenHua Zhang ZhiDong Liu Chieh-Wen Gao Xuan P. A. 《Nano Research》2020,13(5):1332-1338
Nano Research - We report the composition and back-gate voltage tuned transport properties of ternary compound Bi2(Te1−xSex)3 nanowires synthesized by chemical vapor deposition (CVD). It is... 相似文献
92.
Dr. Lina Liang Tong-You Wade Wei Pei-Yu Wu Wouter Herrebout Ming-Daw Tsai Prof. Stéphane P. Vincent 《Chembiochem : a European journal of chemical biology》2020,21(20):2982-2990
d -Glycero-d -manno-heptose-1β,7-bisphosphate (HBP) and d -glycero-d -manno-heptose-1β-phosphate (H1P) are bacterial metabolites that were recently shown to stimulate inflammatory responses in host cells through the activation of the TIFA-dependent NF-κB pathway. To better understand structure-based activity in relation to this process, a family of nonhydrolyzable phosphonate analogues of HBP and H1P was synthesized. The inflammation modulation by which these molecules induce the TIFA-NF-κB signal axis was evaluated in vivo at a low-nanomolar concentration (6 nM) and compared to that of the natural metabolites. Our data showed that three phosphonate analogues had similar stimulatory activity to HBP, whereas two phosphonates antagonized HBP-induced TIFA-NF-κB signaling. These results open new horizons for the design of pro-inflammatory and innate immune modulators that could be used as vaccine adjuvant. 相似文献
93.
94.
95.
96.
Zu Guoqing Lu Yukuan Yan Yi Zhang Xiaoming Zhao Jingwei Du Wei Ran Xu Jiang Zhengyi 《Metals and Materials International》2020,26(2):248-259
Metals and Materials International - The flow behaviour and microstructure characteristics of a ferritic stainless steel were investigated using plain strain compression test on a Gleeble 3500... 相似文献
97.
98.
99.
Covalent triazine frameworks (CTFs) have been recently employed for visible light-driven photocatalysis due to their unique optical and electronic properties. However, the usually highly hydrophobic nature of CTFs, which originates from their overall aromatic backbone, leads to limitations of CTFs for applications in aqueous media. In this study, we aim to extend the range of the application media of CTFs and design hybrid material of a CTF and mesoporous silica (SBA-15) for efficient photocatalysis in aqueous medium. A thiophene-containing CTF was directly synthesized in mesopores of SBA-15. Due to the high surface area and the added hydrophilic properties by silica, the hybrid material demonstrated excellent adsorption of organic molecules in water. This leads not only to high photocatalytic performance of the hybrid material for the degradation of organic dyes in water, but also for efficient photocatalysis in solvent-free and solid state. Furthermore, the reusability, stability and easy recovery of the hybrid material offers promising metal-free heterogeneous photocatalyst for broader applications in different reaction media. 相似文献
100.
In this research, the three‐dimensional structural and colorimetric modeling of three‐dimensional woven fabrics was conducted for accurate color predictions. One‐hundred forty single‐ and double‐layered woven samples in a wide range of colors were produced. With the consideration of their three‐dimensional structural parameters, three‐dimensional color prediction models, K/S‐, R‐, and L*a*b*‐based models, were developed through the optimization of previous two‐dimensional models which have been reported to be the three most accurate models for single‐layered woven structures. The accuracy of the new three‐dimensional models was evaluated by calculating the color differences ΔL*, ΔC*, Δh°, and ΔECMC(2:1) between the measured and the predicted colors of the samples, and then the error values were compared to those of the two‐dimensional models. As a result, there has been an overall improvement in color predictions of all models with a decrease in ΔECMC(2:1) from 10.30 to 5.25 units on average after the three‐dimensional modeling. 相似文献