全文获取类型
收费全文 | 1264篇 |
免费 | 19篇 |
专业分类
电工技术 | 44篇 |
综合类 | 1篇 |
化学工业 | 242篇 |
金属工艺 | 21篇 |
机械仪表 | 14篇 |
建筑科学 | 18篇 |
矿业工程 | 1篇 |
能源动力 | 70篇 |
轻工业 | 117篇 |
水利工程 | 2篇 |
无线电 | 129篇 |
一般工业技术 | 222篇 |
冶金工业 | 319篇 |
原子能技术 | 18篇 |
自动化技术 | 65篇 |
出版年
2022年 | 14篇 |
2021年 | 21篇 |
2020年 | 8篇 |
2019年 | 10篇 |
2018年 | 14篇 |
2017年 | 23篇 |
2016年 | 18篇 |
2015年 | 14篇 |
2014年 | 25篇 |
2013年 | 46篇 |
2012年 | 47篇 |
2011年 | 53篇 |
2010年 | 32篇 |
2009年 | 38篇 |
2008年 | 32篇 |
2007年 | 44篇 |
2006年 | 38篇 |
2005年 | 41篇 |
2004年 | 28篇 |
2003年 | 39篇 |
2002年 | 39篇 |
2001年 | 33篇 |
2000年 | 25篇 |
1999年 | 35篇 |
1998年 | 124篇 |
1997年 | 84篇 |
1996年 | 44篇 |
1995年 | 38篇 |
1994年 | 33篇 |
1993年 | 36篇 |
1992年 | 14篇 |
1991年 | 14篇 |
1990年 | 14篇 |
1989年 | 7篇 |
1988年 | 12篇 |
1987年 | 15篇 |
1986年 | 17篇 |
1985年 | 13篇 |
1984年 | 14篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 7篇 |
1980年 | 13篇 |
1977年 | 5篇 |
1976年 | 15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1283条查询结果,搜索用时 15 毫秒
71.
The formation of modulated structures and GP zones in Al-Mg alloys aged at low temperatures was investigated using the mechanical
properties, electrical resistivity measurements, and high resolution electron microscopy. It was shown in TEM investigations
that a modulated structure was present in Al-10 wt pct Mg alloys at the beginning of low temperature aging which grew into
GP zones having the Ll2 structure distributed periodically along the [100] direction. The miscibility gaps for GP zone formation and the spinodal
temperature were determined from the results of resistivity measurements. It is suggested that in Al-Mg alloys spinodal decomposition
can occur at the beginning of low temperature aging.
Y. KOJIMA, formerly with Tokyo Institute of Technology 相似文献
72.
In emulsion polymerization, the Smith and Ewart theory gives about two or three times the number of polymer particles obtained by experiment. In this paper, a reaction model is proposed which, from the standpoint of reactor design, can give an adequate explanation of the whole course of an emulsion polymerization of monomer highly insoluble in water. Among other things, the generating process of polymer particles is examined in detail. It is demonstrated experimentally that a new parameter proposed here, which represents the degree of difficulty of monomer initiation in micelles, is indispensable in explaining that process. Also confirmed is that monomer initiation takes place more easily in polymer particles than in micelles. According to the new model, the progress of polymerization, i.e., monomer conversion, the number of the polymer particles, and properties of polymer thus produced can be estimated with satisfactory accuracy. Furthermore, approximate equations are derived for easier estimation. 相似文献
73.
Standard soil samples contaminated with various standard cyanocompounds were prepared. Column elution experiments and analyses were conducted. Compounds with an easy capacity for dissociation to ions, such as KCN and potassium hexacyanoferrate(III), were found to be eluted by forming free cyanide even in fresh water. Hexacyanoferrate(II) salts, such as potassium hexacyanoferrate(II) and iron(III) hexacyanoferrate(II), were found not to be dissociated in water, but were dissociated and diffused under alkaline conditions (pH >13). Hexacyanoferrate(II) ion was found to be more easily dissociated in water with a higher pH.Column tests as above were also conducted for soil samples taken from a former paint ink factory using iron(III) hexacyanoferrate(II), cyanogen chloride, potassium cyanate, copper cyanide, as well as potassium cyanide, as raw materials. It was demonstrate that iron(III) hexacyanoferrate(II) was dissociated and eluted under alkaline conditions. The elution rate was reduced when the contaminated soil was sandwiched with standard soil layers.Further, it was found that the Fe(CN)(6)(4-) ion eluted with NaOH from hexacyanoferrate acid in soil, were easily decomposed into cyanic acid or other byproducts by UV with the addition of ozone and H(2)O(2). 相似文献
74.
Preparation of plastic spherical microlenses by use of a fluoropolymer stencil and oil-bath heating 总被引:1,自引:0,他引:1
A new method for fabricating plastic spherical microlenses was developed, which allowed self-alignment of lenses and self-organized formation of a spherical shape. First a low-surface-energy fluoropolymer thin film was deposited and patterned as a stencil. Then photosensitive phenol resin was patterned on it as the lens material. Finally the resin was annealed in an oil bath to form a sphere. The molten phenol resin spontaneously formed a sphere and positioned itself in the center of the fluoropolymer ring pattern as a result of the difference of surface free energy and the equivalently zero-gravity condition in the oil bath. When a light-emitting-diode printer head was loaded with spherical microlenses, its optical output increased by 1 order of magnitude. 相似文献
75.
Kenji M. Kojima Shin-ichi Uchida Yasunori Fudamoto Setsuko Tajima 《Journal of Low Temperature Physics》2003,131(5-6):775-779
Josephson plasma reflectivity edge in YBa2Cu3O6.6 (T
c=59 K) was measured in parallel magnetic fields HCuO2 up to 7 T. Upon application of the field, the Josephson plasma edge splits to two reflectivity edges, forming a new peak at finite frequency. Optical conductivity obtained by Kramers–Kronig analysis indicates that a new transverse Josephson plasma mode appears under parallel fields. We propose that the new mode originates from the modulation of the insulating layers with and without Josephson vortices, as has been suggested by free-energy calculations of Josephson vortices with moderate densities. 相似文献
76.
We examined the biological effects of porcine enamel matrix derivative (EMD; Emdogain) on the formation of reparative dentine and dentine bridges in rat molars after pulp amputation. The pulp chambers of upper molars of Wistar rats were perforated and the amputated pulp surfaces were directly capped with either EMD or its carrier propylene glycol alginate (PGA) as control. The cavities were then restored with glass-ionomer cement. On post-amputation days 4-30, the dissected maxillae were examined by light and electron microscopy. In PGA-capped pulp, reparative dentine had been formed over the dentine walls under the prepared cavity on day 7 post-amputation and its thickness extended until day 30. On day 30, as well as reparative dentine formation, diffuse calcification had occurred beneath the amputated wound surfaces. Dentine bridge formation under the amputated coronal pulp surface was observed in 18.2% of amputated pulp on day 30. In EMD-capped pulp, reparative dentine had already been formed by odontoblast-like cells over the dentine walls, already on day 4 post-amputation, and its thickness extended until day 30. The Ca and P weight % and Ca/P ratio of reparative dentine matrix were similar to those of pre-existing dentine matrix, and these values were not different between PGA and EMD-capped pulp. Dentine bridge formation was observed in 27.3% of EMD-capped pulp on day 30. Our results suggest that EMD enhances the formation of both reparative dentine and dentine bridges during wound healing of amputated rat molar pulp. 相似文献
77.
Kojima K Hiratsuka A Suzuki H Yano K Ikebukuro K Karube I 《Analytical chemistry》2003,75(5):1116-1122
An electrochemical protein chip was microfabricated. A thin-film three-electrode system, including an array of 36 platinum working electrodes, a set of thin-film Ag/AgCl electrodes, and platinum auxiliary electrodes, was integrated on a glass substrate. Capture antibodies were immobilized in a 4.5-nm-thick double layer of a hexamethyldisiloxane plasma-polymerized film. Because of their highly cross-linked network structure, the capture antibodies could be firmly immobilized. No nonspecific adsorption was observed during a series of procedures to detect target proteins, and electrochemical cross talk between neighboring sites was negligible. The sandwich immunoassay was conducted on a single chip using model proteins, alpha-1-fetoprotein and beta2-microglobulin. A distinct current increase following the oxidation of hydrogen peroxide produced by the enzymatic reaction of glucose oxidase was observed, which indicates that the capture proteins could actually bind the target proteins. Two kinds of protein were detected independently on multiple sites with respective capture antibodies. 相似文献
78.
The influence of moving auditory stimuli on standing balance in healthy young adults and the elderly 总被引:3,自引:0,他引:3
The maintenance of postural balance depends on effective and efficient feedback from various sensory inputs. The importance of auditory inputs in this respect is not, as yet, fully understood. The purpose of this study was to analyse how the moving auditory stimuli could affect the standing balance in healthy adults of different ages. The participants of the study were 12 healthy volunteers, who were divided into two age categories: the young group (mean = 21.9 years) and the elderly group (mean = 68.9 years). The instrument used for evaluation of standing balance was a force plate for measuring body sway parameters. The toe pressure was measured using the F-scan Tactile Sensor System. The moving auditory stimulus produced a white-noise sound and binaural cue using the Beachtron Affordable 3D Audio system. The moving auditory stimulus conditions were employed by having the sound come from the right to left or vice versa at the height of the participant's ears. Participants were asked to stand on the force plate in the Romberg position for 20 s with either eyes opened or eyes closed for analysing the effect of visual input. Simultaneously, all participants tried to remain in the standing position with and without auditory stimulation that the participants heard from the headphone. In addition, the variables of body sway were measured under four conditions for analysing the effect of decreased tactile sensation of toes and feet soles: standing on the normal surface (NS) or soft surface (SS) with and without auditory stimulation. The participants were asked to stand in a total of eight conditions. The results showed that the lateral body sway of the elderly group was more influenced than that of the young group by the lateral moving auditory stimulation. The analysis of toe pressure indicated that all participants used their left feet more than their right feet to maintain balance. Moreover, the elderly had the tendency to be stabilized mainly by use of their heels. The young group were mainly stabilized by the toes of their feet. The results suggest that the elderly may need a more appropriate stimulus of tactile and auditory sense as a feedback system than the young for maintaining and control of their standing postures. 相似文献
79.
A 50-mJ green beam was generated at a 1-kHz repetition rate by intracavity frequency doubling of a quasi-cw laser-diode-pumped Nd:YAG laser. The green laser was used for 12-mJ fourth-harmonic beam generation with a CsLiB(6)O(10) crystal. 相似文献
80.
Kojima T Kishi M Sekita S Satake M 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2001,42(3):202-205
The aim of this study is to clarify whether sennosides are contained in the leaf of Malva verticillata L., and then to clarify the source of sennosides in health teas including malva leaves. The identification and determination of sennosides were performed with thin layer chromatography and high performance liquid chromatography. The leaf of Malva verticillata L. did not contain sennosides A or B and could be easily distinguished from senna leaf. Our previous report showed that sennosides are contained in weight-reducing herbal teas including malva leaves, and that senna leaf is a herbal component in some teas. Furthermore, in 10 samples of health tea including malva leaves that were bought last year, the smallest amount of sennosides was 6.1 mg/bag, and all health teas including malva leaves contained the leaf and midrib of senna. We suggest that sennosides A and B are not contained in the leaf of Malva verticillata L., and that the sennosides in health teas including malva leaves are not derived from malva leaf but from senna leaf. 相似文献