全文获取类型
收费全文 | 11010篇 |
免费 | 1001篇 |
国内免费 | 441篇 |
专业分类
电工技术 | 515篇 |
综合类 | 667篇 |
化学工业 | 1907篇 |
金属工艺 | 571篇 |
机械仪表 | 785篇 |
建筑科学 | 878篇 |
矿业工程 | 293篇 |
能源动力 | 339篇 |
轻工业 | 1003篇 |
水利工程 | 217篇 |
石油天然气 | 386篇 |
武器工业 | 53篇 |
无线电 | 1290篇 |
一般工业技术 | 1368篇 |
冶金工业 | 568篇 |
原子能技术 | 176篇 |
自动化技术 | 1436篇 |
出版年
2024年 | 34篇 |
2023年 | 181篇 |
2022年 | 371篇 |
2021年 | 456篇 |
2020年 | 372篇 |
2019年 | 277篇 |
2018年 | 336篇 |
2017年 | 363篇 |
2016年 | 354篇 |
2015年 | 473篇 |
2014年 | 617篇 |
2013年 | 735篇 |
2012年 | 746篇 |
2011年 | 800篇 |
2010年 | 650篇 |
2009年 | 704篇 |
2008年 | 626篇 |
2007年 | 561篇 |
2006年 | 589篇 |
2005年 | 463篇 |
2004年 | 311篇 |
2003年 | 307篇 |
2002年 | 331篇 |
2001年 | 255篇 |
2000年 | 225篇 |
1999年 | 228篇 |
1998年 | 203篇 |
1997年 | 127篇 |
1996年 | 148篇 |
1995年 | 107篇 |
1994年 | 87篇 |
1993年 | 66篇 |
1992年 | 56篇 |
1991年 | 51篇 |
1990年 | 41篇 |
1989年 | 32篇 |
1988年 | 21篇 |
1987年 | 17篇 |
1986年 | 14篇 |
1985年 | 13篇 |
1984年 | 8篇 |
1983年 | 10篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 12篇 |
1976年 | 14篇 |
1973年 | 4篇 |
1969年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Chenchen Zhou Jia Man Haibo Yu He Xia Luming Man Bin Qi Jianfeng Li 《Ceramics International》2021,47(8):10866-10872
Ceramic microparticles have great potentials in various fields such as materials engineering, biotechnology, microelectromechanical systems, etc. Morphology of the microparticle performs an important role on their application. To date, it remains difficult to find an effective and controllable way for fabricating nonspherical ceramic microparticles with 3D features. This work demonstrates a method that combines UV light lithography and single emulsion opaque-droplet-templated microfluidic molding to prepare the crescent-shaped ceramic microparticles. By tailoring the intensity of UV light and flow rate of fluid, the shapes of microparticles are accordingly tuned. Therefore, varieties of crescent-shaped microparticles and their variations have been fabricated. After sintering, the crescent-shaped alumina ceramic microparticles were obtained. Benefitting from the light absorption and scattering behavior of most ceramic nanoparticles, this system can serve as a general platform to produce crescent-shaped microparticles made from different materials, and hold great potentials for applications in microrobotics, structural materials in MEMS, and biotechnology. 相似文献
2.
Zhang Nan Zhao Man Liu Guangfa Wang Jiaoyang Chen Yunzhi Zhang Zhengjian 《Journal of Materials Science》2022,57(19):8687-8700
Journal of Materials Science - A green modification method for effectively enhancing toughness of PLA was established. Herein, alkaline lignin (LG) was firstly alkylated with dodecane, and then... 相似文献
3.
4.
Multimedia Systems - The preferences of Web information purchasers are changing. Cost-effectiveness (i.e., an emphasis on performance with respect to price) is becoming less regarded than... 相似文献
5.
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
6.
7.
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
8.
9.
Yu Zhang Xiaofei Dai Haonan Jin Chaoxin Man Yujun Jiang 《Journal of dairy science》2021,104(4):4023-4032
This study aimed to predict the optimal carbon source for higher production of exopolysaccharides (EPS) by Lactobacillus paracasei TD 062, and to evaluate the effect of this carbon source on the production and monosaccharide composition of EPS. We evaluated the EPS production capacity of 20 strains of L. paracasei under the same conditions. We further investigated L. paracasei TD 062, which showed the highest EPS-producing activity (0.609 g/L), by examining the associated biosynthesis pathways for EPS. Genomics revealed that fructose, mannose, trehalose, glucose, galactose, and lactose were carbon sources that L. paracasei TD 062 could use to produce EPS. We identified an EPS synthesis gene cluster that could participate in transport, export, and sugar chain synthesis, and generate 6 sugar nucleotides. Experimental results showed that the sugar content of the EPS produced using fermentation with the optimized carbon source (fructose, mannose, trehalose, glucose, galactose, and lactose) increased by 115%. Furthermore, use of the optimized carbon source changed the monosaccharide content of the associated EPS. The results of enzyme activity measurements showed significant increases in the activity of 2 key enzymes involved in the glycoside synthesis pathway. Our study revealed that optimizing the carbon source provided for fermentation not only increased the production of EPS, but also affected the composition of the monosaccharides by increasing enzyme activity in the underlying synthesis pathways, suggesting an important role for carbon source in the production of EPS by L. paracasei TD 062. 相似文献
10.
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