全文获取类型
收费全文 | 570465篇 |
免费 | 6490篇 |
国内免费 | 1538篇 |
专业分类
电工技术 | 10372篇 |
综合类 | 482篇 |
化学工业 | 84689篇 |
金属工艺 | 27787篇 |
机械仪表 | 20189篇 |
建筑科学 | 11774篇 |
矿业工程 | 4087篇 |
能源动力 | 13981篇 |
轻工业 | 35857篇 |
水利工程 | 6969篇 |
石油天然气 | 14455篇 |
武器工业 | 26篇 |
无线电 | 63206篇 |
一般工业技术 | 121848篇 |
冶金工业 | 98768篇 |
原子能技术 | 14050篇 |
自动化技术 | 49953篇 |
出版年
2021年 | 4805篇 |
2020年 | 3696篇 |
2019年 | 4753篇 |
2018年 | 13508篇 |
2017年 | 13831篇 |
2016年 | 12097篇 |
2015年 | 5742篇 |
2014年 | 9119篇 |
2013年 | 24546篇 |
2012年 | 15928篇 |
2011年 | 24190篇 |
2010年 | 20364篇 |
2009年 | 21358篇 |
2008年 | 21852篇 |
2007年 | 22854篇 |
2006年 | 15354篇 |
2005年 | 15815篇 |
2004年 | 14283篇 |
2003年 | 14000篇 |
2002年 | 12717篇 |
2001年 | 12270篇 |
2000年 | 11622篇 |
1999年 | 11839篇 |
1998年 | 29480篇 |
1997年 | 20588篇 |
1996年 | 15770篇 |
1995年 | 11748篇 |
1994年 | 10355篇 |
1993年 | 10444篇 |
1992年 | 7682篇 |
1991年 | 7412篇 |
1990年 | 7392篇 |
1989年 | 6998篇 |
1988年 | 6718篇 |
1987年 | 6040篇 |
1986年 | 5961篇 |
1985年 | 6530篇 |
1984年 | 6013篇 |
1983年 | 5561篇 |
1982年 | 5121篇 |
1981年 | 5378篇 |
1980年 | 4968篇 |
1979年 | 5031篇 |
1978年 | 5172篇 |
1977年 | 5558篇 |
1976年 | 7227篇 |
1975年 | 4513篇 |
1974年 | 4389篇 |
1973年 | 4476篇 |
1972年 | 3925篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
Wireless Personal Communications - Multiple inputs multiple outputs (MIMO) is a reliable technique which can manage the increased wireless data traffic in the future generation of wireless... 相似文献
42.
Belov M. I. Anashin D. V. Kabdin N. E. Storchevoy V. F. Sudnik Yu. A. 《Russian Engineering Research》2022,42(11):1110-1116
Russian Engineering Research - The stability of robot-mower motion in a specific direction is considered. The direction is regulated by means of an angular sensor and a programmable controller... 相似文献
43.
Kumar S. Ganesh Sridhar S. S. Hussain Azham Manikanthan S. V. Padmapriya T. 《Multimedia Tools and Applications》2022,81(7):9091-9109
Multimedia Tools and Applications - Discovering the relevant web services for specific applications in the dynamically changing business world becomes very critical. Researchers have used many... 相似文献
44.
Mohammed Amin Salih Venkatachalam K. Hubálovský S. Trojovský P. Prabu P. 《Mobile Networks and Applications》2022,27(3):1050-1059
Mobile Networks and Applications - 5G/6G communication are first generation high speed wireless communication network which integrates the aerial data, terrestrial data and maritime data via... 相似文献
45.
Kruglikov S. S. Zagorskii D. L. Kolesnikov V. A. Doludenko I. M. Bedin S. A. 《Theoretical Foundations of Chemical Engineering》2021,55(5):942-951
Theoretical Foundations of Chemical Engineering - The effect of the electrolyte composition, mass-transfer conditions, pore diameter, interpore distance, and electric parameters on the formation of... 相似文献
46.
L.J. Espinoza-Pérez S. Esquivel-Medina E. López-Honorato 《Ceramics International》2021,47(11):15527-15532
The influence of the microstructure on the corrosion rate of three monolithic SiC samples in FLiNaK salt at 900 °C for 250 h was studied. The SiC samples, labeled as SiC-1, SiC-2, and SiC-3, had corrosion rates of 0.137, 0.020, and 0.043 mg/cm2h, respectively. Compared with grain size and the presence of special grain boundaries (i.e., Σ3), the content of high-angle grain boundaries (HAGBs) appeared to have the strongest influence on the corrosion rate of SiC in FLiNaK salt, since the corrosion rate increased six times as the concentration of high-angle grain boundaries increased from 19 to 32% for SiC-2 and SiC-1, respectively. These results stress the importance of controlling the content of HAGBs during the production process of SiC. 相似文献
47.
Andrade R. G. S. A. de Oliveira A. E. Guerra V. G. 《Theoretical Foundations of Chemical Engineering》2022,56(4):504-512
Theoretical Foundations of Chemical Engineering - The corona onset voltage is an important operating parameter in the electrostatic precipitation of nanoparticulate, however, its experimental... 相似文献
48.
Margarita A. Sazonova Vasily V. Sinyov Anastasia I. Ryzhkova Marina D. Sazonova Tatiana V. Kirichenko Victoria A. Khotina Zukhra B. Khasanova Natalya A. Doroschuk Vasily P. Karagodin Alexander N. Orekhov Igor A. Sobenin 《International journal of molecular sciences》2021,22(2)
Chronic stress is a combination of nonspecific adaptive reactions of the body to the influence of various adverse stress factors which disrupt its homeostasis, and it is also a corresponding state of the organism’s nervous system (or the body in general). We hypothesized that chronic stress may be one of the causes occurence of several molecular and cellular types of stress. We analyzed literary sources and considered most of these types of stress in our review article. We examined genes and mutations of nuclear and mitochondrial genomes and also molecular variants which lead to various types of stress. The end result of chronic stress can be metabolic disturbance in humans and animals, leading to accumulation of reactive oxygen species (ROS), oxidative stress, energy deficiency in cells (due to a decrease in ATP synthesis) and mitochondrial dysfunction. These changes can last for the lifetime and lead to severe pathologies, including neurodegenerative diseases and atherosclerosis. The analysis of literature allowed us to conclude that under the influence of chronic stress, metabolism in the human body can be disrupted, mutations of the mitochondrial and nuclear genome and dysfunction of cells and their compartments can occur. As a result of these processes, oxidative, genotoxic, and cellular stress can occur. Therefore, chronic stress can be one of the causes forthe occurrence and development of neurodegenerative diseases and atherosclerosis. In particular, chronic stress can play a large role in the occurrence and development of oxidative, genotoxic, and cellular types of stress. 相似文献
49.
Multicomponent Diamond-Like Semiconductors Based on the InBV–CdS System: Bulk and Surface Properties
Semiconductors - According to developed methods, in the fields of the mutual solubility of initial binary compounds (InP, InSb, and CdS), solid solutions of the InP–CdS and InSb–CdS... 相似文献
50.
Silicon - The products of solid-phase mechanochemical interaction between pyrocatechol and silicon dioxide yielding a powdered composite were studied using a number of physicochemical methods. This... 相似文献