全文获取类型
收费全文 | 1046篇 |
免费 | 14篇 |
专业分类
电工技术 | 39篇 |
综合类 | 1篇 |
化学工业 | 187篇 |
金属工艺 | 15篇 |
机械仪表 | 12篇 |
建筑科学 | 14篇 |
能源动力 | 63篇 |
轻工业 | 70篇 |
水利工程 | 2篇 |
无线电 | 124篇 |
一般工业技术 | 169篇 |
冶金工业 | 302篇 |
原子能技术 | 15篇 |
自动化技术 | 47篇 |
出版年
2022年 | 6篇 |
2021年 | 13篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 11篇 |
2017年 | 22篇 |
2016年 | 12篇 |
2015年 | 11篇 |
2014年 | 16篇 |
2013年 | 33篇 |
2012年 | 34篇 |
2011年 | 34篇 |
2010年 | 23篇 |
2009年 | 29篇 |
2008年 | 27篇 |
2007年 | 36篇 |
2006年 | 29篇 |
2005年 | 29篇 |
2004年 | 24篇 |
2003年 | 34篇 |
2002年 | 31篇 |
2001年 | 26篇 |
2000年 | 18篇 |
1999年 | 33篇 |
1998年 | 117篇 |
1997年 | 81篇 |
1996年 | 40篇 |
1995年 | 35篇 |
1994年 | 31篇 |
1993年 | 32篇 |
1992年 | 14篇 |
1991年 | 13篇 |
1990年 | 13篇 |
1989年 | 7篇 |
1988年 | 10篇 |
1987年 | 15篇 |
1986年 | 15篇 |
1985年 | 6篇 |
1984年 | 14篇 |
1983年 | 6篇 |
1982年 | 10篇 |
1981年 | 7篇 |
1980年 | 13篇 |
1977年 | 2篇 |
1976年 | 13篇 |
1975年 | 3篇 |
1972年 | 5篇 |
1971年 | 2篇 |
1969年 | 2篇 |
1968年 | 3篇 |
排序方式: 共有1060条查询结果,搜索用时 15 毫秒
81.
82.
Y Naya M Kojima H Honjyo A Ochiai O Ukimura H Watanabe 《Canadian Metallurgical Quarterly》1998,24(5):771-773
Recently, we reported that ultrasound-estimated bladder weight (UEBW) could be used as a noninvasive tool in evaluating the degree of bladder hypertrophy. This study was designed to test the reproducibility of its measurement. The overall mean UEBW of the initial measurement and that of the second one by one observer in 36 cases was 42.8 +/- 22.6 g and 42.9 +/- 22.6 g, respectively. The paired differences between two measurements ranged from -3.4 to 2.7 g, with a mean difference of only -0.1 g. The interobserver variance was also slight. The paired differences between UEBW measurements derived from the two observers in 32 cases ranged from -6.0 to 7.9 g, with a mean difference of only 0.1 g. The Cochran's test statistic of the measurements of UEBW was 0.142 for one observer and 0.130 for two, which were less than its 5% critical value. Due to these favorable characteristics, UEBW could be reliable tool for the investigation of bladder hypertrophy with a sufficient reproducibility. 相似文献
83.
M Kojima 《Canadian Metallurgical Quarterly》1997,55(5):1252-1260
New fluoroquinolones have potent and broad antimicrobial activity and spectra, respectively, against gram-positive and -negative bacteria including P. aeruginosa. As a result of their frequent use, bacterial resistance to the quinolones has gradually developed and limited their therapeutic efficacy in infections, especially, with P. aeruginosa, S. pneumoniae, S. aureus (especially MRSA), and N. gonorrhoeae. Bacterial resistance to the quinolones probably results from : 1) mutations with chromosomal genes of DNA gyrase or DNA topoisomerase in E. coli and S. aureus, 2) decreased permeability of the cell envelope through OmpF, porin-forming protein, in gram-negative bacteria, and 3) activation of active efflux-mediated permeability through the cell membrane protein, either NorA in S. aureus or Opr in P. aeruginosa. Proper use of the quinolones is also proposed to prevent emergence of the bacterial resistance. 相似文献
84.
Kin Kiong Lee Ishida Y. Ohshima T. Kojima K. Tanaka Y. Takahashi T. Okumura H. Arai K. Kamiya T. 《Electron Device Letters, IEEE》2003,24(7):466-468
We present results of the enhancement mode, n-channel 3C-silicon carbide (SiC) MOSFETs fabricated on homoepitaxy 3C-SiC films. The fabricated devices exhibit excellent gate-controlled linear and saturation regimes of operation. The average effective channel mobility is found to be 229 cm/sup 2//Vs. The breakdown field of the gate oxide is observed at be 11 MV/cm and the subthreshold swing is determined to be 280 mV/decade. 相似文献
85.
The stability of a CIS solar mini-module during a light/dark cycle and continuous light irradiation was investigated. Under both test conditions, the maximum power was improved during the early stages, then subsequently deteriorated. The major factors causing this phenomenon were changes in the fill-factor and open circuit voltage. The details of some parameters relevant to these factors are considered herein. In addition, the dependencies of light intensity and temperature in terms of the I–V characteristics were measured. 相似文献
86.
Higher order effects such as third-order dispersion, shock effect, and soliton self-frequency shift on all-optical logic gates that use asymmetric nonlinear optical fiber couplers are investigated with the beam propagation method, and it is found that third-order dispersion seriously affects the operations of logic devices. In contrast to the case of nonvanishing third-order dispersion, the radiation is stimulated, and consequently the operations of the logic devices are degraded. In order to diminish the degradation, the bandwidth limited amplification is introduced. The logic functions can be improved by trapping only the soliton components in the finite gain-bandwidth 相似文献
87.
A ternary alloy of polyamide-6 (PA), poly(phenyleneether) (PPE), and rubber has a three-phase structure, in which PPE particles with rubber inclusions are dispersed in a PA matrix. This is an excellent thermoplastic with high impact strength and high heat resistance. To understand the morphology-properties relationship, we undertook a two-dimensional finite element method (FEM) analysis on the deformation mechanism of the ternary alloy. A three-phase model was constructed so that five hybrid particles of PPE-shell and rubber-core were embedded in the PA matrix. When the model was deformed at room temperature, the rubber domain induced yielding of the PPE-shell and the PA-matrix and at large strains the yielded zone expanded to pervade the whole space. This suggests that the toughening mechanism is essentially the same as in the binary alloy of PA and rubber (rubber-toughened PA). At higher temperatures (e.g., at 100°C) the stress concentration occurred not only in the PA matrix but also in the PPE-shell. It implies that the PPE-shell is highly responsible for bulk deformation, even though it is part of the dispersed phase. At high temperatures, the rigidity of PPE affects the alloy bulk rigidity so that the ternary system exhibits high heat resistance. 相似文献
88.
N. Kamada A. Yamaguchi G. Motoyama A. Sumiyama Y. Aoki Y. Okuda H. Kojima 《Journal of Low Temperature Physics》2014,175(1-2):37-43
Experimental exploration of highly spin-polarized states of liquid 3He by applying external magnetic field is limited by the availability of static magnetic field. In the “ferromagnetic” superfluid A1 phase of liquid 3He there is an alternate method for boosting spin-polarization by the process of spin pumping without requiring such high magnetic field. The spin pumping in the A1 phase takes advantage of a superleak (SL) acting simultaneously as a filter for both entropy and spin. The spin pump technique that uses the SL-spin filter and a mechanical actuator enables us to directly boost polarization of 3He. The amount of enhancement of spin polarization has been limited so far. We are now developing a new type of SL filter made of packed aluminum oxide powder (referred as PAP-SL), in order to achieve greater enhancement of spin polarization. Several kinds of the PAP-SL filter were constructed by pressing aluminum oxide powders into a cylinder holder. The packed structures were carefully characterized by a flow-rate-measurement, X-ray tomography, and mercury intrusion porosimetry. The preliminary result shows that the PAP-SL works as SL filter for the superfluid 3He. 相似文献
89.
Naka R. Watanabe K. Kawarabayashi J. Uritani A. Iguchi T. Hayashi N. Kojima N. Yoshida T. Kaneko J. Takeuchi H. Kakuta T. 《IEEE transactions on nuclear science》2001,48(6):2348-2351
The purpose of this study is to develop a radiation distribution monitor using a normal plastic optical fiber. The monitor has a long operating length and can obtain continuous radiation distributions. A principle of the position sensing is based on a time-of-flight technique. The monitor is sensitive to beta rays or charged particles, gamma rays, and fast neutrons. The spatial resolutions for beta-rays ( 90Sr-90Y), gamma-rays (137Cs), and D-T neutrons are 30, 37, and 13 cm, respectively. The detection efficiencies for the beta-rays, gamma-rays, and D-T neutrons are 0.11%, 1.6×10 -5% and 1.2×10-4%, respectively. The effective attenuation length of the detection efficiency is 18 m. In this paper, we describe the basic characteristics of this monitor 相似文献
90.
We describe a 6 year old girl with chorea following cardiac surgery, the first such report in Japan. The radical operation for total anomalous pulmonary venous return was carried out at the age of 11 months under hypothermia. Seven days after the operation, a sudden onset of irritability, dysphagia, chorea, generalized, hypotonia, and complete external ophthalmoplegia were seen. These symptoms diminished gradually, but chorea remained. We speculated that the cause of chorea arose from the cardiac surgery under hypothermia. It is necessary to consider 'cardiac surgery' as one of the triggers of certain movement disorders including chorea. We tried treatment with haloperidol, pimozide, and several other drugs; only pimozide was effective in decreasing chorea without any side-effects. 相似文献