全文获取类型
收费全文 | 6259篇 |
免费 | 228篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 111篇 |
综合类 | 8篇 |
化学工业 | 1154篇 |
金属工艺 | 167篇 |
机械仪表 | 92篇 |
建筑科学 | 258篇 |
矿业工程 | 56篇 |
能源动力 | 115篇 |
轻工业 | 610篇 |
水利工程 | 41篇 |
石油天然气 | 16篇 |
无线电 | 481篇 |
一般工业技术 | 1027篇 |
冶金工业 | 1658篇 |
原子能技术 | 52篇 |
自动化技术 | 646篇 |
出版年
2023年 | 45篇 |
2022年 | 65篇 |
2021年 | 140篇 |
2020年 | 95篇 |
2019年 | 94篇 |
2018年 | 116篇 |
2017年 | 89篇 |
2016年 | 125篇 |
2015年 | 103篇 |
2014年 | 138篇 |
2013年 | 341篇 |
2012年 | 220篇 |
2011年 | 280篇 |
2010年 | 215篇 |
2009年 | 236篇 |
2008年 | 245篇 |
2007年 | 243篇 |
2006年 | 208篇 |
2005年 | 190篇 |
2004年 | 133篇 |
2003年 | 154篇 |
2002年 | 147篇 |
2001年 | 104篇 |
2000年 | 117篇 |
1999年 | 122篇 |
1998年 | 344篇 |
1997年 | 224篇 |
1996年 | 189篇 |
1995年 | 118篇 |
1994年 | 109篇 |
1993年 | 111篇 |
1992年 | 65篇 |
1991年 | 49篇 |
1990年 | 78篇 |
1989年 | 77篇 |
1988年 | 57篇 |
1987年 | 72篇 |
1986年 | 60篇 |
1985年 | 73篇 |
1984年 | 69篇 |
1983年 | 51篇 |
1982年 | 48篇 |
1981年 | 44篇 |
1980年 | 54篇 |
1979年 | 38篇 |
1978年 | 58篇 |
1977年 | 82篇 |
1976年 | 103篇 |
1975年 | 50篇 |
1974年 | 45篇 |
排序方式: 共有6492条查询结果,搜索用时 31 毫秒
1.
Zenan Yu Julian Moore Jean Calderon Lei Zhai Jayan Thomas 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(39):5289-5295
Cable‐shaped supercapacitors (SCs) have recently aroused significant attention due to their attractive properties such as small size, lightweight, and bendability. Current cable‐shaped SCs have symmetric device configuration. However, if an asymmetric design is used in cable‐shaped supercapacitors, they would become more attractive due to broader cell operation voltages, which results in higher energy densities. Here, a novel coil‐type asymmetric supercapacitor electrical cable (CASEC) is reported with enhanced cell operation voltage and extraordinary mechanical‐electrochemical stability. The CASECs show excellent charge–discharge profiles, extraordinary rate capability (95.4%), high energy density (0.85 mWh cm−3), remarkable flexibility and bendability, and superior bending cycle stability (≈93.0% after 4000 cycles at different bending states). In addition, the CASECs not only exhibit the capability to store energy but also to transmit electricity simultaneously and independently. The integrated electrical conduction and storage capability of CASECS offer many potential applications in solar energy storage and electronic gadgets. 相似文献
2.
Kooij Julian F. P. Flohr Fabian Pool Ewoud A. I. Gavrila Dariu M. 《International Journal of Computer Vision》2019,127(3):239-262
International Journal of Computer Vision - Anticipating future situations from streaming sensor data is a key perception challenge for mobile robotics and automated vehicles. We address the problem... 相似文献
3.
Juana Maria de Lourdes Medina-Contreras Patrick Mailloux-Salinas Juventino III Colado-Velazquez Norma Leticia Gomez Viquez Gómez-Viquez Rodrigo Velázquez-Espejel Ana del Carmen Susunaga-Notario David Julian Arias-Chávez Guadalupe Bravo 《Journal of the science of food and agriculture》2020,100(7):3212-3219
4.
Aleksandra Czumaj Sylwia Szrok-Jurga Areta Hebanowska Jacek Turyn Julian Swierczynski Tomasz Sledzinski Ewa Stelmanska 《International journal of molecular sciences》2020,21(23)
The importance of coenzyme A (CoA) as a carrier of acyl residues in cell metabolism is well understood. Coenzyme A participates in more than 100 different catabolic and anabolic reactions, including those involved in the metabolism of lipids, carbohydrates, proteins, ethanol, bile acids, and xenobiotics. However, much less is known about the importance of the concentration of this cofactor in various cell compartments and the role of altered CoA concentration in various pathologies. Despite continuous research on these issues, the molecular mechanisms in the regulation of the intracellular level of CoA under pathological conditions are still not well understood. This review summarizes the current knowledge of (a) CoA subcellular concentrations; (b) the roles of CoA synthesis and degradation processes; and (c) protein modification by reversible CoA binding to proteins (CoAlation). Particular attention is paid to (a) the roles of changes in the level of CoA under pathological conditions, such as in neurodegenerative diseases, cancer, myopathies, and infectious diseases; and (b) the beneficial effect of CoA and pantethine (which like CoA is finally converted to Pan and cysteamine), used at pharmacological doses for the treatment of hyperlipidemia. 相似文献
5.
K. Borer G. Czapek F. Hasenbalg M. Hauser S. Janos P. Loaiza U. Moser K. Pretzl C. Schütz P. Wicht S. Wüthrich 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2004,520(1-3):112-115
The ORPHEUS dark matter detector consists of 450 g superconducting tin granules with diameters of 28 and 36 μm. The detector has been operating in the shallow site of the underground laboratory in Bern (70 m.w.e). First preliminary results on WIMP detection sensitivity will be presented. 相似文献
6.
7.
Ting Gang Zhu Uttiya Chowdhury Michael M. Wong Jonathan C. Denyszyn Russell D. Dupuis 《Journal of Electronic Materials》2002,31(5):406-410
In this paper, we report the study of the electrical characteristics of GaN and AlGaN vertical p-i-n junctions and Schottky
rectifiers grown on both sapphire and SiC substrates by metal-organic chemical-vapor deposition. For GaN p-i-n rectifiers
grown on SiC with a relatively thin “i” region of 2 μm, a breakdown voltage over 400 V, and forward voltage as low as 4.5
V at 100 A/cm2 are exhibited for a 60-μm-diameter device. A GaN Schottky diode with a 2-μm-thick undoped layer exhibits a blocking voltage
in excess of ∼230 V at a reverse-leakage current density below 1 mA/cm2, and a forward-voltage drop of 3.5 V at a current density of 100 A/cm2. It has been found that with the same device structure and process approach, the leakage current of a device grown on a SiC
substrate is much lower than a device grown on a sapphire substrate. The use of Mg ion implantation for p-guard rings as planar-edge
terminations in mesageometry GaN Schottky rectifiers has also been studied. 相似文献
8.
9.
Moser L.E. Melliar-Smith P.M. Agrawala V. 《Parallel and Distributed Systems, IEEE Transactions on》1994,5(5):459-473
Presents protocols for determining processor membership in asynchronous distributed systems that are subject to processor and communication faults. These protocols depend on the placement of a total order on broadcast messages. The types of systems for which each of these protocols is applicable are characterized by the properties of the communication mechanisms and by the availability of stable storage. In the absence of stable storage or of a mechanism for distinguishing promptly delivered messages, the authors show that no membership protocol can exist. They also discuss their experience in implementing these membership protocols 相似文献
10.