全文获取类型
收费全文 | 241篇 |
免费 | 5篇 |
专业分类
电工技术 | 11篇 |
化学工业 | 44篇 |
机械仪表 | 2篇 |
建筑科学 | 1篇 |
能源动力 | 6篇 |
轻工业 | 16篇 |
无线电 | 37篇 |
一般工业技术 | 52篇 |
冶金工业 | 55篇 |
原子能技术 | 5篇 |
自动化技术 | 17篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2014年 | 2篇 |
2013年 | 4篇 |
2012年 | 5篇 |
2011年 | 11篇 |
2010年 | 12篇 |
2009年 | 7篇 |
2008年 | 9篇 |
2007年 | 12篇 |
2006年 | 4篇 |
2005年 | 10篇 |
2004年 | 7篇 |
2003年 | 3篇 |
2002年 | 9篇 |
2001年 | 6篇 |
2000年 | 9篇 |
1999年 | 3篇 |
1998年 | 29篇 |
1997年 | 25篇 |
1996年 | 8篇 |
1995年 | 7篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 5篇 |
1978年 | 8篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1974年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有246条查询结果,搜索用时 15 毫秒
71.
Takaaki Inada Tomohiko Hatakeyama Fumio Takemura 《International Journal of Refrigeration》2009,32(3):462-471
Gas-storage ice is the ice that contains various functional gas pores, and can be produced by freezing water in which a desired gas is dissolved. In this conventional method, however, the gas content in the ice is limited by the gas solubility in water. To overcome this limitation, we developed a method to produce gas-storage ice from water in which microbubbles of a desired gas are dispersed, and then obtained images of the structural features of pores formed in the ice prepared using this microbubble method. The images clarified the interaction between a microbubble arriving at an ice–water interface and an existing pore already formed in the ice. The air content in ice prepared using the microbubble method was higher than that prepared using the conventional method, and was about three times higher than the solubility of air in water. 相似文献
72.
Akira Miyamoto Hiromi Kikuchi Hiroaki Onuma Hideyuki Tsuboi Michihisa Koyama Nozomu Hatakeyama Akira Endou Hiromitsu Takaba Momoji Kubo Carlos A. Del Carpio 《Journal of the Society for Information Display》2007,15(5):307-313
Abstract— The tight‐binding quantum chemical molecular dynamics code, Colors, has been successfully applied to the electronic‐structure calculations of the MgO‐protecting‐layer model in plasma‐display panels (PDPs). The code succeeded in reproducing the band‐gap energy of the MgO crystal structure. The energy gap between the bottom of the conduction band (CB) and the top of valence band (VB) was 7.45 eV, which is in quantitative agreement with the experimental and previous theoretical results. The electronic structure of the undoped MgO model and Si‐doped MgO model was also calculated. The impurity level was 2.15 eV lower than that for the bottom of the CB. This result was in qualitative agreement with recent cathodoluminescence measurements. In addition, we have already succeeded in developing a novel electrical conductivity simulator using the spatial distribution of the probability density of wave functions obtained from the tight‐binding quantum chemical molecular dynamics code, Colors. The electrical conductivity of the MgO‐protecting‐layer model was estimated with and without an oxygen defect and a significant change in the electrical conductivity of the MgO‐protecting‐layer materials was observed with the introduction of oxygen defects. 相似文献
73.
A rapid, simple, convenient, and highly efficient transformation of the fission yeast Schizosaccharomyces pombe has been developed. Freezing fission yeast cells in glycerol, a permeating cryoprotectant, with lithium acetate improved remarkably the transformation efficiency by one to two orders of magnitude. The optimum concentration of glycerol was found to be 30%, which is higher than that (10-15%) in the conventional cryopreservation of yeast cells. Glycerol not only played a role in cryopreserving the competent cells but also improved the transformation efficiency of the process. The thawed cell suspension with glycerol and lithium acetate was immediately mixed with carrier DNA, plasmid DNA and polyethylene glycol. Next, the mixture was heat shocked and directly spread on a selection plate. This simple procedure yielded more than 10(6) transformants/microg plasmid DNA, reducing the time required to only 20 min in total, including the thawing time. Furthermore, the frozen competent cells were stored long-term for more than 3 months without any significant loss of efficiency. 相似文献
74.
Temperature dependencies of X-ray diffractograms of lignins and polystyrene derivatives were investigated. Bulky side groups, such as methoxyl functionalities were found to expand intermolecular distance, while hydroxyl groups reduce its mean value. Intermolecular distance expands discontinuously at the temperature corresponding to the glass transition temperature. 相似文献
75.
A practical low loss splicing method based on the discharge fusion for single-mode fibers was developed. Average splice losses of 0.4, 0.2, and 0.1 dB for fibers with 5.2, 7, and 10 μm core diameters, respectively, are obtained by a simple apparatus utilizing the self-alignment effect due to the surface tension of melted fiber ends. The surface tension effect is analyzed both experimentally and theoretically. Experimental splice losses, both after and during heating, coincide with the theoretical estimated values. It was found that the optimum heating temperature for low loss splices is near 2000°C at 8.5 W electric discharge power. Splicing loss causes are examined. The main cause of the practical splice loss is the residual core axis misalignment caused by an insufficient surface tension effect and core eccentricity with respect to cladding. 相似文献
76.
Simple formulas for splice losses have been derived by using the series expansion. The losses are proportional to the square of normalised axial or angular displacement. The coefficient is determined by only the normalised frequency. Normalised frequency dependence measurements of the splice losses show excellent agreement with the theory. 相似文献
77.
Shigemitsu Shin Yuko Hatakeyama Kiyoshi Ogawa Kinya Shimomura 《Materials Research Bulletin》1979,14(1):133-136
A high-temperature form of a brownmillerite-like compound Sr2Fe2O5, which has a perovskite structure with the oxygen vacancies randomly distributed, showed a remarkable NO decomposition at 700–900°C, whereas another brownmillerite-like ferrate (III) of composition Ca2Fe2O5 did not exhibit any significant catalytic activity for NO decomposition over the temperature range from room temperature to 900°C. This difference in their catalytic activities has been explained on the basis of their crystallographic properties, i.e., ordering or disordering of the oxygen deficiencies. 相似文献
78.
Very low OH content optical fibres consisting of P2O5-doped silica core and GeO2-P2O5-B2O3-doped silica cladding were fabricated by the m.c.v.d. technique. The relation between the OH absorption loss and the deposition temperature was clarified. The OH content in this fibre could be reduced to about seven parts per billion (~ 7 × 10?9) by using a low deposition temperature. 相似文献
79.
T. Iseki M. Takahashi H. Hattori T. Hatakeyama H. Hatakeyama 《Food Hydrocolloids》2001,15(4-6):503-506
Viscoelastic properties of xanthan gum aqueous solutions and hydrogels were investigated using a cone-plate type rheometer. The change of viscoelasticity during annealing the solution and cooling to gelation temperature was examined as functions of annealing time, temperature and frequencies. In the annealing process, the storage modulus G′ increases with increasing annealing time. In the subsequent cooling process, G′ of the annealed solution increased, whereas the G′ of non-annealed solution remained almost constant. G′ of hydrogels increased with the increase of annealing temperature and concentration. Based on the experimental results obtained, the structural change of the solution in the annealing process and the structure of gels were investigated. 相似文献
80.
Hatakeyama H. Tamanuki T. Mori K. Ae T. Sasaki T. Yamaguchi M. 《Photonics Technology Letters, IEEE》2001,13(5):418-420
A uniform and high performance eight-channel spot-size-converter integrated SOA (SSC-SOA) array for optical switching gate applications is demonstrated. Bow-shaped waveguides are used to achieve high gain and high ON-OFF ratio switching. All channels of the fabricated eight-channel array show a high fiber-to-fiber gain of 12.7 dB, low polarization-dependent gain (PDG) of <0.5 dB, and a high ON-OFF ratio of >50 dB at a low drive current of 40 mA 相似文献