全文获取类型
收费全文 | 2572篇 |
免费 | 89篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 113篇 |
综合类 | 2篇 |
化学工业 | 701篇 |
金属工艺 | 49篇 |
机械仪表 | 63篇 |
建筑科学 | 41篇 |
矿业工程 | 1篇 |
能源动力 | 65篇 |
轻工业 | 163篇 |
水利工程 | 2篇 |
无线电 | 165篇 |
一般工业技术 | 539篇 |
冶金工业 | 425篇 |
原子能技术 | 153篇 |
自动化技术 | 183篇 |
出版年
2023年 | 10篇 |
2022年 | 49篇 |
2021年 | 58篇 |
2020年 | 40篇 |
2019年 | 46篇 |
2018年 | 39篇 |
2017年 | 50篇 |
2016年 | 65篇 |
2015年 | 47篇 |
2014年 | 49篇 |
2013年 | 134篇 |
2012年 | 95篇 |
2011年 | 147篇 |
2010年 | 95篇 |
2009年 | 103篇 |
2008年 | 114篇 |
2007年 | 116篇 |
2006年 | 96篇 |
2005年 | 84篇 |
2004年 | 84篇 |
2003年 | 67篇 |
2002年 | 68篇 |
2001年 | 54篇 |
2000年 | 56篇 |
1999年 | 59篇 |
1998年 | 165篇 |
1997年 | 113篇 |
1996年 | 81篇 |
1995年 | 53篇 |
1994年 | 63篇 |
1993年 | 47篇 |
1992年 | 27篇 |
1991年 | 24篇 |
1990年 | 21篇 |
1989年 | 26篇 |
1988年 | 27篇 |
1987年 | 18篇 |
1986年 | 21篇 |
1985年 | 21篇 |
1984年 | 20篇 |
1983年 | 9篇 |
1982年 | 7篇 |
1981年 | 14篇 |
1980年 | 18篇 |
1979年 | 9篇 |
1978年 | 11篇 |
1977年 | 9篇 |
1976年 | 21篇 |
1975年 | 4篇 |
1973年 | 3篇 |
排序方式: 共有2665条查询结果,搜索用时 15 毫秒
91.
Masao Shibuya Motoshi Kato Masaki Ozawa P. H. Fang Eiji Ōsawa 《Fullerenes, Nanotubes and Carbon Nanostructures》2013,21(2):181-193
Abstract It was confirmed that soot produced by free burning of small hydrocarbons like benzene and cyclohexane generally contains less than 0.1 ppm of C60. Small, but measurable amounts of C60 were found in two samples of charcoal, providing the first indication of fullerene formation in the solid state. 相似文献
92.
93.
94.
In this study, both naturally occurring and artificial amino acids were successfully transformed into the corresponding urethane derivatives using diphenyl carbonate. The urethanes thus prepared could be efficiently cyclized into amino acid N‐carboxyanhydrides (NCAs) without the requirement of phosgene. In addition, the presence of primary amines converted the urethane derivatives into NCAs and initiated the ring‐opening polymerization of the in situ formed NCAs, allowing for the well‐defined synthesis of polypeptides. These polypeptides contained initiating ends functionalized by an amine‐derived residue and propagating ends bearing the reactive amino group. By precise control of the structures of the polypeptides, various polypeptide conjugates such as block copolymers and graft copolymers were successfully synthesized as designed, and their applications in antifouling coatings against proteins, drug delivery systems and biosensors were demonstrated. © 2019 Society of Chemical Industry 相似文献
95.
Thermal Spray Using a High-Frequency Pulse Detonation Combustor Operated in the Liquid-Purge Mode 总被引:1,自引:0,他引:1
T. Endo R. Obayashi T. Tajiri K. Kimura Y. Morohashi T. Johzaki K. Matsuoka T. Hanafusa S. Mizunari 《Journal of Thermal Spray Technology》2016,25(3):494-508
Experiments on thermal spray by pulsed detonations at 150 Hz were conducted. Two types of pulse detonation combustors were used, one operated in the inert gas purge (GAP) mode and the other in the liquid-purge (LIP) mode. In both modes, all gases were supplied in the valveless mode. The GAP mode is free of moving components, although the explosive mixture is unavoidably diluted with the inert gas used for the purge of the hot burned gas. In the LIP mode, pure fuel-oxygen combustion can be realized, although a liquid-droplet injector must be actuated cyclically. The objective of this work was to demonstrate a higher spraying temperature in the LIP mode. First, the temperature of CoNiCrAlY particles heated by pulsed detonations was measured. As a result, the spraying temperature in the LIP mode was higher than that in the GAP mode by about 1000 K. Second, the temperature of yttria-stabilized zirconia (YSZ) particles, whose melting point was almost 2800 °C, heated by pulsed detonations in the LIP mode was measured. As a result, the YSZ particles were heated up to about 2500 °C. Finally, a thermal spray experiment using YSZ particles was conducted, and a coating with low porosity was successfully deposited. 相似文献
96.
97.
Thermodynamic Properties of Ionic Semiclathrate Hydrate Formed with Tetrabutylammonium Propionate
下载免费PDF全文
![点击此处可从《化学工程与技术》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The phase equilibrium temperature and dissociation heat of tetrabutylammonium propionate (TBAPr) hydrate are reported. TBAPr hydrate is a type of ionic semiclathrate hydrates and also could potentially be used as thermal energy storage material. The temperature‐composition phase diagram of the TBAPr hydrate was determined in a defined range of mass fractions. Considering the dissociation heat of differential scanning calorimetry (DSC) measurements, multiple peaks of heat flow were observed in the TBAPr‐water system at the TBAPr mass fraction lower than 0.35, and there was a single peak at the mass fraction higher than 0.37. 相似文献
98.
Operation Assist by Vibration Suppression Control Using Impulse‐Shaped Signals for Power Assist Conveyance System
下载免费PDF全文
![点击此处可从《Electrical Engineering in Japan》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yuichi Yamamoto Masaki Uchida Yoshifumi Morita Susumu Hara 《Electrical Engineering in Japan》2014,186(2):31-39
This paper presents an assist control method for a flexible parts conveyance task using a power assist conveyance system. The assist control method should be designed so as not only to suppress vibration but also to reduce the degradation of operating feel. For this purpose, multiple impulse‐shaped signals are used as feedforward signals in order to reduce the vibration of flexible parts during conveyance. In addition, the adjustment time is introduced to adjust the input timing of the impulse‐shaped signal and to suppress vibration. In order to improve the degradation of operating feel, the smaller amplitudes of the three impulse‐shaped signals are used and input repeatedly. The effectiveness of the proposed system was verified experimentally. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(2): 31–39, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22476 相似文献
99.
Effects of Atmospheric Composition on the Molecular Structure of Synthesized Silicon Oxycarbides
下载免费PDF全文
![点击此处可从《Journal of the American Ceramic Society》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Masaki Narisawa Fuji Funabiki Akihiro Iwase Fumihiro Wakai Hideo Hosono 《Journal of the American Ceramic Society》2015,98(10):3373-3380
The dependence of silicon oxycarbides' chemical composition and molecular structure on their reaction conditions was tested by varying the atmosphere under which pyrolysis was performed. To obtain the silicon oxycarbides, densely cross‐linked silicone resin particles with an averaged diameter of 2 μm were pyrolyzed in various atmospheres of H2, Ar, and CO2, in the temperature range 700°C–1100°C. The residual mass of resin after pyrolysis was almost constant at 700°C, although their apparent colors varied distinctly. The sample obtained from the H2 atmosphere was white, whereas that obtained from the CO2 atmosphere was dark brown. Fourier‐transform infrared (FT‐IR) spectra of the residues suggested that the Si–O–Si network evolution was accelerated in the CO2 atmosphere. Beyond 800°C, the chemical compositions of the compounds obtained from a H2 atmosphere increasingly approached near‐stoichiometric SiO2–xSiC composition with increasing the pyrolysis temperature. Compounds from a CO2 atmosphere approached a composition of SiO2–xC with no free SiC as the pyrolysis temperature increased. In the products from an Ar atmosphere, SiO2–xSiC–yC compositions were typically obtained. The observed effects of the pyrolysis atmosphere on the resulting chemical compositions were analyzed in terms of thermodynamic calculations. Electron spin resonance (ESR) spectra revealed broad and intense signals from products obtained from either Ar or CO2. Estimating from the signal intensity, the residual spin concentrations were in the range 1018–1019 g?1. Meanwhile, the spectra from the samples obtained in H2 showed weak and sharp signals with estimated spin concentrations ranging from 1016–1017 g?1. This signal attenuation may have been due to the hydrogen capping of dangling bond formed during pyrolysis. 相似文献
100.
Cationic polymerization behavior of β‐methylglycidyl ether derivatives and physical properties of their cationically cured materials
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
β‐Methylglycidyl ethers have been applied to Electrical and Electronic adhesives. However, there is no report about the detailed polymerization behavior and physical properties of their cured products. Hence, we investigated cationic polymerization behavior of bisphenol A di(β‐methylglycidyl) ether (Me‐BADGE) and physical properties of the cured products containing Me‐BADGE. DSC analysis suggested that Me‐BADGE could be cured completely at lower temperature than bisphenol A diglycidyl ether (BADGE). Physical properties were analyzed by dynamic viscoelastic analysis. Glass transition temperature (Tg) of BADGE homopolymer was 194°C. In contrast, the copolymer of BADGE (50 wt %) with Me‐BADGE (50 wt %) showed Tg at 124°C. According to the data of E’ and tan δ, crosslink density of the cured products decreased with increasing the Me‐BADGE content. The analysis of cationic polymerization of monofunctional β‐methylglycidyl ether suggested that the cationic polymerization proceeded not only through oxonium cation but also through carbocation formed by ring‐opening reaction of oxonium cation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42377. 相似文献