全文获取类型
收费全文 | 8419篇 |
免费 | 658篇 |
国内免费 | 321篇 |
专业分类
电工技术 | 371篇 |
综合类 | 479篇 |
化学工业 | 1438篇 |
金属工艺 | 360篇 |
机械仪表 | 552篇 |
建筑科学 | 739篇 |
矿业工程 | 209篇 |
能源动力 | 270篇 |
轻工业 | 540篇 |
水利工程 | 189篇 |
石油天然气 | 440篇 |
武器工业 | 55篇 |
无线电 | 1017篇 |
一般工业技术 | 1068篇 |
冶金工业 | 438篇 |
原子能技术 | 161篇 |
自动化技术 | 1072篇 |
出版年
2024年 | 24篇 |
2023年 | 126篇 |
2022年 | 229篇 |
2021年 | 332篇 |
2020年 | 276篇 |
2019年 | 221篇 |
2018年 | 261篇 |
2017年 | 279篇 |
2016年 | 283篇 |
2015年 | 367篇 |
2014年 | 432篇 |
2013年 | 510篇 |
2012年 | 552篇 |
2011年 | 568篇 |
2010年 | 495篇 |
2009年 | 508篇 |
2008年 | 446篇 |
2007年 | 408篇 |
2006年 | 417篇 |
2005年 | 352篇 |
2004年 | 255篇 |
2003年 | 217篇 |
2002年 | 224篇 |
2001年 | 177篇 |
2000年 | 188篇 |
1999年 | 205篇 |
1998年 | 173篇 |
1997年 | 134篇 |
1996年 | 149篇 |
1995年 | 91篇 |
1994年 | 92篇 |
1993年 | 62篇 |
1992年 | 52篇 |
1991年 | 52篇 |
1990年 | 38篇 |
1989年 | 36篇 |
1988年 | 14篇 |
1987年 | 14篇 |
1986年 | 15篇 |
1985年 | 18篇 |
1984年 | 14篇 |
1983年 | 11篇 |
1982年 | 11篇 |
1981年 | 4篇 |
1980年 | 13篇 |
1979年 | 5篇 |
1978年 | 14篇 |
1977年 | 9篇 |
1976年 | 9篇 |
1974年 | 3篇 |
排序方式: 共有9398条查询结果,搜索用时 15 毫秒
1.
This paper is prepared in honour of Professor E.T. Brown for his outstanding contributions to rock mechanics and geotechnical engineering and also for his personal influence on the first author's research career in geomechanics and geotechnical engineering. As a result, we have picked a topic that reflects two key research areas in which Professor E.T. Brown has made seminal contributions over a long and distinguished career. These two areas are concerned with the application of the critical state concept to modelling geomaterials and the analysis of underground excavation or tunnelling in geomaterials.Partially due to Professor Brown's influence, the first author has also been conducting research in these two areas over many years. In particular, this paper aims to describe briefly the development of a unified critical state model for geomaterials together with an application to cavity contraction problems and tunnelling in soils. 相似文献
2.
3.
4.
Dr. Yahu A. Liu Dr. Qihui Jin Qiang Ding Dr. Xueshi Hao Tingting Mo Shanshan Yan Dr. Yefen Zou Dr. Zhihong Huang Xiaoyue Zhang Wenqi Gao Dr. Tom Y.-H. Wu Chun Li Dr. Badry Bursalaya Dr. Michael Di Donato Dr. You-Qing Zhang Lisa Deaton Dr. Weijun Shen Dr. Brandon Taylor Anwesh Kamireddy Dr. George Harb Dr. Jing Li Dr. Yong Jia Dr. Andrew M. Schumacher Dr. Bryan Laffitte Dr. Richard Glynne Dr. Shifeng Pan Dr. Peter McNamara Dr. Valentina Molteni Dr. Jon Loren 《ChemMedChem》2020,15(16):1562-1570
Loss of β-cell mass and function can lead to insufficient insulin levels and ultimately to hyperglycemia and diabetes mellitus. The mainstream treatment approach involves regulation of insulin levels; however, approaches intended to increase β-cell mass are less developed. Promoting β-cell proliferation with low-molecular-weight inhibitors of dual-specificity tyrosine-regulated kinase 1A (DYRK1A) offers the potential to treat diabetes with oral therapies by restoring β-cell mass, insulin content and glycemic control. GNF4877, a potent dual inhibitor of DYRK1A and glycogen synthase kinase 3β (GSK3β) was previously reported to induce primary human β-cell proliferation in vitro and in vivo. Herein, we describe the lead optimization that lead to the identification of GNF4877 from an aminopyrazine hit identified in a phenotypic high-throughput screening campaign measuring β-cell proliferation. 相似文献
5.
6.
7.
Xiangrong Ma Rui Dang Ning Yang Xiao Li Ya zhang Ying Gong Zhipan Liu Wei Guo Yuanyuan Zhang Chunyan Li 《International Journal of Hydrogen Energy》2021,46(44):22842-22851
The high cost of noble metal catalysts has been a great bottleneck for the catalyst industry. Using the noble metal at a single-atom level for catalytic applications could dramatically decrease the cost. The impacts of single Pt atoms on the photocatalytic performance of Ag3VO4 have been investigated and reported. In this report, single Pt atoms were anchored on the surface of Ag3VO4 (AVO) as a cocatalyst, and the resultant composite photocatalyst has been studied for photocatalytic H2 production from water driven by visible light. The as-prepared AVO particles are hollow nanospheres in the monoclinic phase with a bandgap of 2.20 eV. The light absorption edge of AVO/Pt is slightly red-shifted compared to that of the pristine AVO, indicating more visible light absorption of AVO/Pt. The XPS peaks of Ag, V, and Pt exhibit a significant shift after AVO and Pt get into contact, suggesting the strong interaction between the surface Ag and V atoms, and single Pt atoms. After 3-h illumination, the photocatalytic H2 evolution amount from AVO/Pt is improved up to 1400 μmol, which is 2.8 times that on the bare AVO. Such efficient photocatalytic H2 evolution on AVO/Pt is still maintained after five reaction cycles. The better photocatalytic performance of AVO/Pt has been attributed to the more efficient visible light utilization and the lower interfacial charge transfer resistance, as demonstrated in the DRS and EIS spectra. The presence of the surface Pt atoms also leads to a higher amount of reactive radicals, which could efficiently promote the surface redox reactions. 相似文献
8.
UML在网络安全监控系统建模中的应用 总被引:4,自引:0,他引:4
本文首先介绍了UML的特性,然后运用UML对网络安全监控系统中的数据采集系统进行了可视化的建模,建立了系统的需求模型和设计模型的各种视图,最后总结了用UML进行系统需求分析和设计的优越性. 相似文献
9.
中国大陆PCB产业自动化的现况与未来 总被引:1,自引:1,他引:0
从中国大陆PCB发展的现况分析实行设备自动化连线为企业所创造的价值。设备自动化连线是中国大陆PCB必须面临的改革出路。 相似文献
10.
Yong Zhang Yuanlong Mo Xiaolan Zhou Jianqing Li 《Journal of Infrared, Millimeter and Terahertz Waves》2003,24(12):2085-2094
Recently disk-loaded waveguide has been widely used in high-power traveling wave tubes (HPTWT). It has been shown in many experiments that the interaction efficiency and output power can be increased greatly by injecting plasma into the vacuum microwave device. Using field analysis, the dispersion characteristics and the interaction impedance of the disk-loaded waveguide filled with plasma are analyzed in a strong longitudinal magnetic field. In conclusion, the frequency of the TM01 mode increases as the density of the plasma increases. It also can be found when the plasma density increases to a large scale, the TM01 mode of the disk-loaded waveguide overlaps the TG mode, these two modes couple each other and form the new hybrid modes. 相似文献