全文获取类型
收费全文 | 369篇 |
免费 | 22篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 30篇 |
化学工业 | 114篇 |
金属工艺 | 9篇 |
机械仪表 | 11篇 |
建筑科学 | 13篇 |
能源动力 | 25篇 |
轻工业 | 37篇 |
石油天然气 | 11篇 |
无线电 | 20篇 |
一般工业技术 | 51篇 |
冶金工业 | 4篇 |
原子能技术 | 17篇 |
自动化技术 | 50篇 |
出版年
2023年 | 3篇 |
2022年 | 13篇 |
2021年 | 24篇 |
2020年 | 7篇 |
2019年 | 12篇 |
2018年 | 12篇 |
2017年 | 13篇 |
2016年 | 20篇 |
2015年 | 15篇 |
2014年 | 12篇 |
2013年 | 24篇 |
2012年 | 23篇 |
2011年 | 37篇 |
2010年 | 20篇 |
2009年 | 26篇 |
2008年 | 17篇 |
2007年 | 26篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 12篇 |
2003年 | 8篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1998年 | 6篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1977年 | 4篇 |
1974年 | 1篇 |
排序方式: 共有392条查询结果,搜索用时 31 毫秒
101.
This paper proposes a new V/f control method for permanent magnetic synchronous motors (PMSMs) without a position sensor. The proposed method uses state feedback control based on an n–t coordinate system, and controls rotational speed and the voltage amplitude. The t‐axis is a tangent line of a constant voltage ellipse, and the n‐axis is a normal line of the ellipse. The t‐axis current is utilized to place the poles of the transfer function at the desired position at low‐speed and high‐speed conditions. The effectiveness of the proposed method was verified by simulation and experimental results. 相似文献
102.
This paper proposes a filter design for improving the control performance of the current control system of permanent magnet synchronous motors (PMSMs) using the overmodulation region of an inverter. The control performance of a vector control system for PMSMs using the overmodulation region of an inverter can be improved by suppressing harmonic components that are generated in this region. This paper utilizes band elimination filter (BEF) to eliminate harmonic components; however, unsuitable BEF setting leads to generation of large current oscillation at the resonant frequency of current feedback loop with BEF. In order to deal with these problems, the proposed filter design focuses on gain setting at the cutoff frequency of BEF. The proposed filter design can prevent the generation of current oscillation at the resonant frequency of the system, and can improve current control performance without complex adjustments. Simulations and experiments are carried out to show the effectiveness of the proposed BEF setting. 相似文献
103.
Yosuke Kawamoto 《Journal of Nuclear Science and Technology》2017,54(2):213-222
The accurate prediction of the decay heat is essential, especially for nuclear power plant safety purposes. However, it is known that the decay heat predicted by nuclear fuel burn-up calculations is uncertain because of uncertainty of nuclear data employed in the calculations. If the decay heat uncertainty can be reduced, the safety margin of the predicted decay heat can also be reduced, and feasible design ranges of various types of equipments related to the decay heat can be extended. In the present study, we use the nuclear data adjustment method for the decay heat uncertainty reduction with several types of the experimental data. As a result, we clarify that the decay heat uncertainty with short- and long-term cooling periods can be reduced by this method with appropriate experimental data. 相似文献
104.
Toshinori Sugimoto Yosuke Atsumi Manabu Kikuta Masaki Yamagata 《Journal of power sources》2010,195(18):6153-10248
An ionic liquid electrolyte containing bis(fluorosulfonyl)imide (FSI) anion without any solvent is applied to a silicon-nickel-carbon (Si-Ni-carbon) composite anode for rechargeable lithium (Li)-ion batteries. The FSI-based ionic liquid electrolyte successfully provides a stable, reversible capacity for the Si-Ni-carbon anode, which is comparable to the performance observed in a typical commercialized solvent-based electrolyte, while a common ionic liquid electrolyte containing bis(trifluoromethanesulfonyl)imide (TFSI) anion without FSI presents no reversible capacity to the anode at all. Ac impedance analysis reveals that the FSI-based electrolyte provides very low interfacial and charge-transfer resistances at the Si-based composite anode, even when compared to the corresponding resistances observed in a typical solvent-based electrolyte. Galvanostatic cycling of the Si-based composite anode in the FSI-based electrolyte with a charge limitation of 800 mAh g−1 is stable and provides a discharge capacity of 790 mAh g−1 at the 50th cycle, corresponding to a cycle efficiency of 98.8%. 相似文献
105.
Katsuyoshi Hoshino Yosuke Oikawa Ichiro Sakabe Toshiki Komatsu 《Electrochimica acta》2009,55(1):165-170
The electrochromic properties of 1,1′-dibenzyl-4,4′-bipyridinium and 1,1′-diheptyl-4,4′-bipyridinium were investigated in the presence of MBr (M = Li+, Na+, and K+). The cyclic voltammograms of these viologens showed a white-coloured state in addition to the usual violet one-electron reduction state and the colourless divalent state. Chemical analyses (FT-IR and XPS spectra) of the white film and some control experiments with different supporting electrolytes, MX (X = Cl− and I−), revealed that the viologens formed water-insoluble ion pairs with tribromide generated by the electrooxidation of monobromide to produce a white film. The film was reversibly decolourized electrochemically to the initial transparent state, providing the polyelectrochromism using the simple viologen/MBr systems. The colouration efficiencies for the violet and the white-coloured states were 170 cm2/C and 104 cm2/C, respectively. 相似文献
106.
Yosuke Shimizu Satoshi Kadowaki Kiyoshi Ohishi Tadashi Hata Takashi Sano Shinobu Yasukawa 《Electrical Engineering in Japan》2009,169(4):55-64
The improvement of adhesion characteristics is very important for electric trains. The drive system of electric trains must have fine anti‐slip and anti‐skid readhesion controls. In order to achieve the required adhesion, we have already proposed an anti‐slip/skid readhesion control system based on disturbance observer and sensorless vector control. Moreover, we have already applied the proposed method to actual electric multiple unit trains Series 205‐5000. In this paper, using the experimental results of Series 205‐5000 and the numerical simulation results, we evaluate the proposed anti‐slip/skid readhesion control system and confirm that the system has the desired driving wheel torque response. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(4): 55–64, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20834 相似文献
107.
Masashi KotobukiYuji Suzuki Kiyoshi Kanamura Yosuke SatoKazuhiro Yamamoto Toshihiro Yoshida 《Journal of power sources》2011,196(22):9815-9819
In order to fabricate large scale all-solid-state Li battery, we suggested a novel structure of solid electrolyte, which is composed of porous electrolyte supported by honeycomb-type electrolyte. A possibility of fabrication of the honeycomb-supported porous electrolyte and a compatibility of this structure with all-solid-state battery were examined using LLT (Li0.35La0.55TiO3) solid electrolyte which is one of the anticipated solid electrolytes due to its high Li ion conductivity. A porous layer membrane with 3 dimensionally ordered (3DOM) macroporous structure was prepared by a colloidal crystal templating method. The porous honeycomb was fabricated by pushing the membrane into holes of honycomb using a needle followed by calcination. The 3DOM membrane and honeycmb electrolyte were sintered well each other. After filling the 3DOM pores with LiMn2O4 cathode material, the compatibility of this novel porous honeycomb electrolyte with all-solid-state battery was examined. The LiMn2O4/porous honeycomb cell clearly demonstrated charge and discharge behaviors, indicating the porous honeycomb structure can be applied to the all-solid-state battery. The discharge capacity was 71 mA h g−1 (1.3 mA h cm−2) at 30 °C. 相似文献
108.
Yosuke Matsuo Yusuke Fujita Sachiko Ohnishi Takashi Tanaka Hideaki Hirabaru Takanori Kai Hiroshi Sakaida Shoko Nishizono Isao Kouno 《Food chemistry》2010
Chemical constituents of the leaves of rabbiteye blueberry (Vaccinium ashei READE) were investigated in detail. The major phenolic components were caffeoyl quinic acids, flavonol glycosides, flavan-3-ols and proanthocyanidins. Catechins and proanthocyanidins having additional phenylpropanoid units, such as cinchonains, kandelins and mururins, characterised the polyphenols of this plant. Among them, vaccinin A, an isomer of mururin A, was found to be a new compound, and the structure was characterised by spectroscopic methods. The most abundant polyphenols (11.3% of freeze-dried leaves) were oligomeric proanthocyanidins. Thiol degradation with mercaptoethanol indicated that the polymer was constituted of (+)-catechin and (−)-epicatechin as the terminal units and (−)-epicatechin, procyanidin A-2, and cinchonains Ia and Ib as the extension units. Mass spectral analysis suggested the presence of at least dodecamers with A-type linkages and phenylpropanoid moieties. 相似文献
109.
This paper discusses a 6.6‐kV transformerless STATCOM intended for installation on industrial and utility distribution systems in the near future. In addition, this paper provides experimental results obtained from a laboratory model rate at 200 V and 10 kVA. The authors propose such a control method as to superimpose a sixth harmonic zero‐sequence component on each of three‐phase voltage references. This helps to stabilize the voltage of the inner midpoint in the DC link. As a result, the laboratory model installs two bidirectional buck‐boost choppers on the DC link for the purpose of stabilizing the voltages of two outer midpoints. Experimental results obtained from the laboratory model verify the validity of the system design, giving promise of the viability of the 6.6‐kV transformerless STATCOM. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 168(2): 60–68, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20733 相似文献
110.
Chemistry,Properties, and in Vitro and in Vivo Applications of 2′‐O‐Methoxyethyl‐4′‐thioRNA,a Novel Hybrid Type of Chemically Modified RNA
下载免费PDF全文
![点击此处可从《Chembiochem : a European journal of chemical biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yota Saito Yosuke Hashimoto Mai Arai Noriko Tarashima Tadashi Miyazawa Kazuya Miki Dr. Mayumi Takahashi Prof. Dr. Kazuhiro Furukawa Prof. Dr. Naoshi Yamazaki Prof. Dr. Akira Matsuda Prof. Dr. Tatsuhiro Ishida Prof. Dr. Noriaki Minakawa 《Chembiochem : a European journal of chemical biology》2014,15(17):2535-2540
We report the synthesis, properties, and in vitro and in vivo applications of 2′‐O‐methoxyethyl‐4′‐thioRNA (MOE‐SRNA), a novel type of hybrid chemically modified RNA. In its hybridization with complementary RNA, MOE‐SRNA showed a moderate improvement of Tm value (+3.4 °C relative to an RNA:RNA duplex). However, the results of a comprehensive comparison of the nuclease stability of MOE‐SRNA relative to 2′‐O‐methoxyethylRNA (MOERNA), 2′‐O‐methyl‐4′‐thioRNA (Me‐SRNA), 2′‐O‐methylRNA (MeRNA), 4′‐thioRNA (SRNA), and natural RNA revealed that MOE‐SRNA had the highest stability (t1/2>48 h in human plasma). Because of the favorable properties of MOE‐SRNA, we evaluated its in vitro and in vivo potencies as an anti‐microRNA oligonucleotide against miR‐21. Although the in vitro potency of MOE‐SRNA was moderate, its in vivo potency was significant for the suppression of tumor growth (similar to that of MOERNA). 相似文献