全文获取类型
收费全文 | 2095篇 |
免费 | 78篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 144篇 |
综合类 | 3篇 |
化学工业 | 635篇 |
金属工艺 | 79篇 |
机械仪表 | 66篇 |
建筑科学 | 65篇 |
能源动力 | 106篇 |
轻工业 | 226篇 |
水利工程 | 4篇 |
石油天然气 | 6篇 |
武器工业 | 2篇 |
无线电 | 106篇 |
一般工业技术 | 411篇 |
冶金工业 | 45篇 |
原子能技术 | 59篇 |
自动化技术 | 223篇 |
出版年
2023年 | 9篇 |
2022年 | 20篇 |
2021年 | 59篇 |
2020年 | 26篇 |
2019年 | 29篇 |
2018年 | 37篇 |
2017年 | 40篇 |
2016年 | 57篇 |
2015年 | 34篇 |
2014年 | 77篇 |
2013年 | 151篇 |
2012年 | 126篇 |
2011年 | 134篇 |
2010年 | 116篇 |
2009年 | 134篇 |
2008年 | 129篇 |
2007年 | 106篇 |
2006年 | 93篇 |
2005年 | 81篇 |
2004年 | 61篇 |
2003年 | 46篇 |
2002年 | 59篇 |
2001年 | 38篇 |
2000年 | 44篇 |
1999年 | 31篇 |
1998年 | 44篇 |
1997年 | 32篇 |
1996年 | 41篇 |
1995年 | 28篇 |
1994年 | 29篇 |
1993年 | 31篇 |
1992年 | 23篇 |
1991年 | 20篇 |
1990年 | 18篇 |
1989年 | 20篇 |
1988年 | 16篇 |
1987年 | 10篇 |
1986年 | 18篇 |
1985年 | 18篇 |
1984年 | 16篇 |
1983年 | 12篇 |
1982年 | 8篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1977年 | 12篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1972年 | 3篇 |
排序方式: 共有2180条查询结果,搜索用时 15 毫秒
991.
Tsuyoshi Ito Hideyuki Hosokawa Shintaro Yanagisawa Takashi Ohira Makoto Nagase 《Journal of Nuclear Science and Technology》2021,58(1):23-28
ABSTRACT Hitachi has developed the chemical decontamination method to remove radioactive oxides on structural materials by alternately using a mixed solution of oxalic acid and hydrazine for a reductive process and potassium permanganate or permanganic acid solution for an oxidative process. In the decontamination of carbon steel (CS) by applying oxalic acid, a film of iron(II) oxalate dihydrate that has low solubility is formed on the CS surface. During the formation of iron(II) oxalate dihydrate, Co-60 in the reductive decontamination solution may be incorporated into the formed film. This phenomenon may cause a decrease in the decontamination efficiency of the CS. A corrosion test of CS in a reductive decontamination solution containing Co-60 as tracer was carried out in order to evaluate this recontamination. It was confirmed that Co-60 was incorporated into the iron(II) oxalate dihydrate film, and the amount of Co-60 increased with increasing formation of this film. About 50% of the Co-60 added to the reductive decontamination solution was incorporated into iron(II) oxalate dihydrate formed on the CS and the Co-60 incorporation ratio was proportional to the iron(II) oxalate dihydrate formation. This result means that the recontamination during chemical decontamination of CS can be predicted. 相似文献
992.
Hiromi Hiramatsu Makoto Sakurai Tei Maki Hideo Kameyama 《International Journal of Hydrogen Energy》2017,42(15):9922-9929
Electrochemical etching has been used to obtain aluminum foil with high surface area for use as electrodes in electrolytic capacitors. In this approach, direct current etching first generates straight penetrating microchannels, and then a second etching step enlarges the microchannel diameter. In the present work, we developed catalyst supports using aluminum etched with microchannels as a microreactor. The metal aluminum foil catalyst support obtained by etching contained microchannels with a diameter of 1.0–3.0 μm (10,000–15,000 microchannels/mm2). We stacked membrane layers and evaluated their performance in methanol steam reforming. The performance of the reactors containing stacked membranes improved as the layer number increased. The microchannels in this catalytic membrane could be used as reaction channels, were easy to fabricate at low cost, and could be mass-produced continuously. This novel catalytic membrane support opens up new possibilities for practical fabrication of industrial materials. 相似文献
993.
Misato Yokoe Makoto Sano Honami Shibata Daisuke Shibata Eriko Takayama-Watanabe Kazuo Inaba Akihiko Watanabe 《International journal of molecular sciences》2014,15(9):15210-15224
A protease of sperm in the newt Cynops pyrrhogaster that is released after the acrosome reaction (AR) is proposed to lyse the sheet structure on the outer surface of egg jelly and release sperm motility-initiating substance (SMIS). Here, we found that protease activity in the sperm head was potent to widely digest substrates beneath the sperm. The protease activity measured by fluorescein thiocarbamoyl-casein digestion was detected in the supernatant of the sperm after the AR and the activity was inhibited by 4-(2-aminoethyl) benzenesulfonyl fluoride (AEBSF), an inhibitor for serine or cysteine protease, suggesting the release of serine and/or cysteine proteases by AR. In an in silico analysis of the testes, acrosins and 20S proteasome were identified as possible candidates of the acrosomal proteases. We also detected another AEBSF-sensitive protease activity on the sperm surface. Fluorescence staining with AlexaFluor 488-labeled AEBSF revealed a cysteine protease in the principal piece; it is localized in the joint region between the axial rod and undulating membrane, which includes an axoneme and produces powerful undulation of the membrane for forward sperm motility. These results indicate that AEBSF-sensitive proteases in the acrosome and principal piece may participate in the initiation of sperm motility on the surface of egg jelly. 相似文献
994.
995.
Yasuhisa Oya Xiaochun Li Misaki Sato Kenta Yuyama Makoto Oyaidzu Takumi Hayashi 《Journal of Nuclear Science and Technology》2016,53(3):402-405
The deuterium (D) permeation behaviors for ion-damaged tungsten (W) by 3 keV D2+ and 10 keV C+ were studied. The D permeability was obtained for un-damaged W at various temperatures. For both D2+ and C+ implanted W, the permeability was clearly reduced. But, for the D2+ implanted W, the permeability was recovered by heating at 1173 K and it was almost consistent with that for un-damaged W. In the case of C+ implanted W, the permeability was not recovered even if the sample was heated at 1173 K, indicating that the existence of carbon would prevent the recovery of permeation path in W. In addition, transmission electron microscope (TEM) observation showed the voids were grown by heating at 1173 K and not removed, showing the existence of damages would not largely influence on the hydrogen permeation behavior in W in the present study. 相似文献
996.
The authors propose a novel slider design. The tri-pad slider has three separate air bearing surfaces, one in the front of the slider and the other two in the back of the slider. This design permits the optimization of the air bearing stiffness and flying attitude without changing the minimum flying height. It can minimize the effect of skew angle on the flying height, and offers ample room for a larger size thin film head element. Samples were fabricated and flying characteristics at several velocities, as well as the dynamic flying stability, were investigated. 相似文献
997.
Takehiko Watanabe Hajime Itoh A. Yanagisawa Makoto Hiraishi 《Welding International》2013,27(9):633-639
In this study, the authors applied the ultrasonic welding method to weld A6061 heat treatable aluminium alloy and investigated the effects of clamping load and welding time on the properties of the weld. In addition, in order to improve the strength of the joint, the effectiveness of the ethanol droplet on the faying surface was examined. The following results were obtained. The joint strength increased with clamping load and welding time. The fracture of the joint produced under the welding conditions of 1176 N clamping load and 1.5 s welding time occurred in the base metal. The ethanol droplet on the faying surface successfully produced the joint with a strength equivalent to that of the base metal under the welding conditions of smaller clamping load and shorter welding time than the case without ethanol droplet. The softening around the welded area that was performed with the ethanol droplet was smaller than that in the welded area produced by other methods such as TIG and friction stir welding. The fracture surface of the joint welded with the ethanol droplet was remarkably irregular and rough. A dimple pattern was observed over a wide area, indicating that the welded area was significantly expanded. The ethanol droplet made the temperature of the weld area higher than that without ethanol, resulting in improved joint strength with an increase of the plastic deformation at the interface. 相似文献
998.
999.
1000.
Seung-Jun Yu Makoto Fujimaki Koichi Awazu Kimikazu Sasa 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2008,266(21):4762-4765
Reduction in polarization dependent loss of a planar lightwave circuit was achieved by asymmetric birefringence formed by ion implantation, in which oxygen ions were implanted along a diagonal of a cross-section of the planar lightwave circuit. The induced birefringence has a slow axis along the line perpendicular to the diagonal. In the present research, a decrease in polarization dependent loss of up to 3.7 dB was obtained, indicating that the method is effective for reducing polarization dependent loss. 相似文献