全文获取类型
收费全文 | 468648篇 |
免费 | 4852篇 |
国内免费 | 1079篇 |
专业分类
电工技术 | 8362篇 |
综合类 | 274篇 |
化学工业 | 70896篇 |
金属工艺 | 22908篇 |
机械仪表 | 16192篇 |
建筑科学 | 9760篇 |
矿业工程 | 4288篇 |
能源动力 | 10367篇 |
轻工业 | 29238篇 |
水利工程 | 5868篇 |
石油天然气 | 14753篇 |
武器工业 | 40篇 |
无线电 | 51092篇 |
一般工业技术 | 104412篇 |
冶金工业 | 77062篇 |
原子能技术 | 14597篇 |
自动化技术 | 34470篇 |
出版年
2021年 | 4516篇 |
2019年 | 4275篇 |
2018年 | 7908篇 |
2017年 | 8205篇 |
2016年 | 8616篇 |
2015年 | 4885篇 |
2014年 | 8561篇 |
2013年 | 20066篇 |
2012年 | 12544篇 |
2011年 | 16292篇 |
2010年 | 13205篇 |
2009年 | 14894篇 |
2008年 | 15441篇 |
2007年 | 15060篇 |
2006年 | 12837篇 |
2005年 | 11296篇 |
2004年 | 11024篇 |
2003年 | 11089篇 |
2002年 | 10487篇 |
2001年 | 10785篇 |
2000年 | 10233篇 |
1999年 | 10081篇 |
1998年 | 22900篇 |
1997年 | 16576篇 |
1996年 | 12714篇 |
1995年 | 9799篇 |
1994年 | 8897篇 |
1993年 | 8990篇 |
1992年 | 6933篇 |
1991年 | 6879篇 |
1990年 | 6854篇 |
1989年 | 6534篇 |
1988年 | 6354篇 |
1987年 | 5843篇 |
1986年 | 5698篇 |
1985年 | 6106篇 |
1984年 | 5761篇 |
1983年 | 5537篇 |
1982年 | 5216篇 |
1981年 | 5196篇 |
1980年 | 5144篇 |
1979年 | 5120篇 |
1978年 | 5139篇 |
1977年 | 5638篇 |
1976年 | 7033篇 |
1975年 | 4594篇 |
1974年 | 4639篇 |
1973年 | 4640篇 |
1972年 | 4080篇 |
1971年 | 3625篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Seredin P. V. Radam Ali Obaid Goloshchapov D. L. Len’shin A. S. Buylov N. S. Barkov K. A. Nesterov D. N. Mizerov A. M. Timoshnev S. N. Nikitina E. V. Arsentyev I. N. Sharafidinov Sh. Kukushkin S. A. Kasatkin I. A. 《Semiconductors》2022,56(4):253-258
Semiconductors - Abstract—In our work, we carry out a structural-spectroscopic study of AlGaN/GaN epitaxial layers grown by molecular-beam epitaxy with nitrogen-plasma activation on a hybrid... 相似文献
12.
Kravchenko V. F. Konovalov Ya. Yu. 《Journal of Communications Technology and Electronics》2022,67(8):952-964
Journal of Communications Technology and Electronics - A new design of wavelets based on the convolution of a compactly supported function with a rectangular pulse is proposed and theoretically... 相似文献
13.
Journal of Communications Technology and Electronics - A statistical study of the effectiveness of the non-threshold search procedure for a noise-like phase-shift keyed signal by the delay time is... 相似文献
14.
Boltar K. O. Burlakov I. D. Iakovleva N. I. Vlasov P. V. Lazarev P. S. 《Journal of Communications Technology and Electronics》2022,67(9):1175-1184
Journal of Communications Technology and Electronics - In recent years, there has been a rapid improvement in photonics products due to the use of multilayer heterostructures grown on the basis of... 相似文献
15.
Mobile Networks and Applications - Project MindCatcher is an art/research project which has the intention to explore the potential of interactive artistic environments for measuring and a better... 相似文献
16.
Glass and Ceramics - Ceramic bricks based on low-melting clay and ferro-dust from self-disintegrating, low-carbon, ferrochrome slags, graded from M100 to M175, respectively, were obtained in the... 相似文献
17.
Golam Haider Krishna Sampathkumar Tim Verhagen Lukáš Nádvorník Farjana J. Sonia Václav Valeš Jan Sýkora Peter Kapusta Petr Němec Martin Hof Otakar Frank Yang-Fang Chen Jana Vejpravová Martin Kalbáč 《Advanced functional materials》2021,31(29):2102196
Recent advancements in isolation and stacking of layered van der Waals materials have created an unprecedented paradigm for demonstrating varieties of 2D quantum materials. Rationally designed van der Waals heterostructures composed of monolayer transition-metal dichalcogenides (TMDs) and few-layer hBN show several unique optoelectronic features driven by correlations. However, entangled superradiant excitonic species in such systems have not been observed before. In this report, it is demonstrated that strong suppression of phonon population at low temperature results in a formation of a coherent excitonic-dipoles ensemble in the heterostructure, and the collective oscillation of those dipoles stimulates a robust phase synchronized ultra-narrow band superradiant emission even at extremely low pumping intensity. Such emitters are in high demand for a multitude of applications, including fundamental research on many-body correlations and other state-of-the-art technologies. This timely demonstration paves the way for further exploration of ultralow-threshold quantum-emitting devices with unmatched design freedom and spectral tunability. 相似文献
18.
Automation and Remote Control - A linear-quadratic positional differential game of three persons is considered. Coefficient criteria are established under which there is no Nash equilibrium... 相似文献
19.
S. Sarika S. Abhilash V.S. Sumi S. Rijith 《International Journal of Hydrogen Energy》2021,46(30):16387-16403
A promising electrocatalyst containing variable percentage of V2O5–TiO2 mixed oxide in graphene oxide support was prepared by embedding the catalyst on Cu substrate through facile electroless Ni–Co–P plating for hydrogen evolution reaction. The solvothermal decomposition method was opted for tuning the crystalline characteristics of prepared material. The optimized mixed oxide was well characterized, active sites centres were identified and explained by X-ray diffraction, high resolution tunnelling electron microscopy, scanning electron microscopy coupled with energy dispersive X-ray and X-ray photon spectroscopy analysis. The structural and electronic characteristics of material was done by fourier transform infrared spectroscopy and the electrochemical behaviour of the prepared material was evaluated by using Tafel plot, electrochemical impedance analysis, linear sweep voltammetry, open circuit analysis and chronoamperometry measurements. The results show the enhanced catalytic activity of Ni–Co–P than pure Ni–P plate, due to synergic effect. Moreover, the prepared mixed oxide incorporated Ni–Co–P plate has a high activity towards HER with low over potential of 101 mV, low Tafel slope of 36 mVdec?1, high exchange current density of 9.90 × 10?2 Acm?2. 相似文献
20.
A. Nakano T. Shimazaki M. Sekiya H. Shiozawa K. Ohtsuka A. Aoyagi T. Iwakiri Z. Mikami M. Sato Y. Sugino K. Kinoshita T. Matsuoka T. Imamura Y. Takayama K. Yamamoto 《International Journal of Hydrogen Energy》2021,46(29):15649-15659
Monitoring the temperature in liquid hydrogen (LH2) storage tanks on ships is important for the safety of maritime navigation. In addition, accurate temperature measurement is also required for commercial transactions. Temperature and pressure define the density of liquid hydrogen, which is directly linked to trading interests. In this study, we developed and tested a liquid hydrogen temperature monitoring system that uses platinum resistance sensors with a nominal electrical resistance of approximately 1000 Ω at room temperature, PT-1000, for marine applications. The temperature measurements were carried out using a newly developed temperature monitoring system under different pressure conditions. The measured values are compared with a calibrated reference PT-1000 resistance thermometer. We confirm a measurement accuracy of ±50 mK in a pressure range of 0.1 MPa–0.5 MPa. 相似文献