全文获取类型
收费全文 | 402篇 |
免费 | 4篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 18篇 |
综合类 | 1篇 |
化学工业 | 116篇 |
金属工艺 | 5篇 |
机械仪表 | 8篇 |
建筑科学 | 3篇 |
能源动力 | 20篇 |
轻工业 | 44篇 |
水利工程 | 3篇 |
无线电 | 17篇 |
一般工业技术 | 66篇 |
冶金工业 | 83篇 |
原子能技术 | 6篇 |
自动化技术 | 19篇 |
出版年
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 1篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 8篇 |
2013年 | 14篇 |
2012年 | 14篇 |
2011年 | 21篇 |
2010年 | 13篇 |
2009年 | 13篇 |
2008年 | 16篇 |
2007年 | 22篇 |
2006年 | 19篇 |
2005年 | 12篇 |
2004年 | 16篇 |
2003年 | 15篇 |
2002年 | 14篇 |
2001年 | 10篇 |
2000年 | 12篇 |
1999年 | 11篇 |
1998年 | 34篇 |
1997年 | 31篇 |
1996年 | 11篇 |
1995年 | 10篇 |
1994年 | 5篇 |
1993年 | 7篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 8篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 8篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1971年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有409条查询结果,搜索用时 15 毫秒
1.
Atsushi Narumi Kosei Kawasaki Harumi Kaga Toshifumi Satoh Naoya Sugimoto Toyoji Kakuchi 《Polymer Bulletin》2003,49(6):405-410
Summary
The potato phosphorylase-catalyzed polymerization of α-D-glucose-1-phosphate (G-1-P) onto poly[styrene-block-(4-vinylbenzyl maltohexaoside)] (1) was performed at the molar ratios of [G-l-P]0 and [maltohexaose]0 of 35, 80, and 250. The product was found to be soluble in dimethyl sulfoxide, which was a good solvent for amylose, and
showed the complex-formation with iodine, indicating that the product was assignable to poly[styrene-block-(styrene-graft-amylose)] (2). The quantitative analysis of the liberated phosphoric acid gave the average degree of polymerization o f the glucose unit
(n) as 27, 5 1, and 180 for 2-I, 2-II, and 2-III, respectively.
Received: 29 November 2002/Accepted: 22 December 2002
Correspondence to Toyoji Kakuchi 相似文献
2.
3.
The objectives of this paper are to quantify the effect of Marangini convection on the absorption performance for the ammonia–water absorption process, and to visualize Marangoni convection that is induced by adding a heat transfer additive, n-octanol. A real-time single-wavelength holographic interferometer is used for the visualization using a He–Ne gas laser. The interface temperature is always the highest due to the absorption heat release near the interface. It was found that the thermal boundary layer (TBL) increased faster than the diffusion boundary layer (DBL), and the DBL thickness increased by adding the heat transfer additive. At 5 s after absorption started, the DBL thickness for 5 mass% NH3 without and with the heat transfer additive was 3.0 and 4.5 mm, respectively. Marangoni convection was observed near the interface only in the cases with heat transfer additive. The Marangoni convection was very strong just after the absorption started and it weakened as time elapsed. It was concluded that the absorption performance could be improved by increasing the absorption driving potential (xvb−xvi) and by increasing the heat transfer additive concentration. The absorption heat transfer was enhanced as high as 3.0–4.6 times by adding the heat transfer additive that generated Marangoni convection. 相似文献
4.
Takashi Kashiwagi 《Fire Safety Journal》1981,3(3):185-200
Transmittance of external radiation from a CO2 laser through a boundary layer of decomposition products over a vertical sample surface is measured during the ignition period. The results indicate that there is significant absorption of the external radiation for PMMA, and a lesser but still not negligible amount, for red oak. An increase in gas phase temperature over surface temperature is observed over much of the ignition interval. Using the experimentally measured incident flux at the sample surface, surface temperature history was calculated from a model that included re-radiation and convection losses from the surface, endothermic decomposition and conduction into the material. The results confirm the significant effect of gas phase absorption on surface temperature. Steady-state-derived surface regression rate expression was used for PMMA in this model. The results raise questions about the validity of such data for the dynamic heating conditions during the ignition period. Further studies needed to understand the radiative ignition mechanism are identified. 相似文献
5.
Masashi Kashiwagi 《Journal of Engineering Mathematics》2007,58(1-4):51-66
Based on the momentum and energy conservation principles, a compact calculation formula is analytically derived for the wave-drift
force on a 2-D body floating in a two-layer fluid of finite depth. In a two-layer fluid, two different wave modes (the surface-wave
mode with longer wavelength and the internal-wave mode with shorter wavelength) exist not only in the incident wave but also
in the body-scattered wave, and these wave characteristics are properly incorporated in the obtained formula. It is noted
that, unlike the single-layer case, the wave-drift force can be negative in the incident wave of surface-wave mode, if the
transmitted wave with internal-wave mode is large. Numerical computations are implemented for a Lewis-form body by means of
the boundary-integral-equation method with Green’s function for the two-layer fluid problem. The effects of density ratio,
interface position, and body motions on the wave-drift force are studied, and some important features are found for two-layer
fluids. 相似文献
6.
N Furusyo J Hayashi Y Sawayama Y Kawakami Y Kishihara S Kashiwagi 《Canadian Metallurgical Quarterly》1998,59(5):693-698
Serial changes in hepatitis A virus (HAV) and B virus (HBV) markers were determined from 1970 to 1996 in healthy Japanese residents of a rural area of Okinawa, Japan. All 190 serum samples taken in 1970, 791 in 1980, 708 in 1988, and 523 in 1996 from residents 0 to more than 60 years of age were tested for antibody to HAV (anti-HAV), antibody to hepatitis B core antigen (anti-HBc), and hepatitis B surface antigen (HBsAg). The age-adjusted prevalences of anti-HAV and anti-HBc decreased significantly from 83.9% and 74.9%, respectively, in 1970 to 39.7% and 36.6%, respectively, in 1996. In residents < or = 29 years of age, the prevalences of anti-HAV and anti-HBc decreased significantly from 65.3% and 83.8%, respectively, in 1970 to 0.7% and 8.2%, respectively, in 1996. The age-adjusted HBsAg prevalence decreased significantly from 8.2% in 1980 to 4.1% in 1988. These results indicate that exposure to HAV and HBV infections among Okinawa residents less than 29 years of age is decreasing, probably because of improvements in socioeconomic conditions since 1970. Infection with HBV may be eliminated there in the near future. 相似文献
7.
Harumi Yokokawa Tatsuya Kawada Masayuki Dokiya 《Journal of the American Ceramic Society》1989,72(1):152-153
It has been found that the enthalpy of formation of perovskite compounds, Δf H° (ABO3 , B = transition metais), from binary oxides can be well characterized in terms the tolerance factor, t≡(rA + ro )√2 (rB + ro ), where rA and rB are the radii of A-site ions with 12-coordination and B-site ions with 6-coordination, respectively, and Δf H°=−168 + 270(1 − t) kJ·mol−1 for AI BV O3 , Δf H°=−125 + 1000(1 − t) kJ·mol−1 for AII BIV O3 , and Δf H°=− 90 + 720(1 − t) kJ·mol−1 for AIII BIII O3 . Although the thermodynamic data of K2 NiF4 compounds are not extensive, a similar regularity can be found when use is made of the radii of A-site ions with 9-coordination for the K2 NiF4 compounds. These correlations will be quite useful in predicting. 相似文献
8.
K. C. A. Alam B. B. Saha A. Akisawa T. Kashiwagi 《Chemical Engineering Communications》2004,191(7):981-997
This article aims at clarifying the possible design and operating conditions for silica gel-water adsorption refrigeration cycles driven by near-ambient temperature waste heat sources (between 45 and 75°C) with relatively small regenerating temperature lifts (15 to 45 K). A two-stage silica gel-water advanced adsorption chiller is introduced and a simulation model of the chiller was developed to analyze the influence of operating and design conditions on the system performance (coefficient of performance, COP, and cooling capacity). It was hypothesized that the proposed chiller can be driven by low temperature waste heat at 55°C to produce effective cooling. Simulation results show that the operating conditions such as cycle time and hot and cooling water inlet temperature have an influential effect on cooling capacity and COP. COP is proportional to cycle time and heat transfer coefficient as well as inversely proportional to the cooling water inlet temperature, while there are optimum values of hot water temperature and silica gel weight for maximum COP. Cooling capacity mainly improves with the addition of silica gel weight and decreases as cooling water temperature increases. Simulation results also revealed that the system performance can be improved significantly by setting the design and operating conditions optimally. 相似文献
9.
Fate of the chlorine and fluorine in a sub-bituminous coal during pyrolysis and gasification 总被引:1,自引:0,他引:1
The fate of the chlorine and fluorine present in a sub-bituminous coal from Indonesia during pyrolysis and gasification has been studied with fixed and entrained bed reactors. The rate profile for HCl evolved in the temperature programmed pyrolysis exhibits the main and shoulder peaks at 480 and 600 °C, respectively. Model experiments and subsequent Cl 2p XPS measurements show that HCl reacts with metal impurities and carbon active sites at 500 °C to be retained as inorganic and organic chlorine forms, from which HCl evolves again at elevated temperatures. It is suggested that the HCl observed in the coal pyrolysis may originate from the above-mentioned chlorine functionalities formed by secondary reactions involving the nascent char. In the CO2 gasification of the 900 °C char at 1000 °C and 2.5 MPa, any measurable amounts of HCl and HF could not be detected even at a high conversion of 75 wt% (daf), suggesting the accumulation of these halogens in the residual char. When the coal is injected into an O2-blown, entrained bed gasifier at 1200-1400 °C under 2.6 MPa, the partial oxidation proceeds to a larger extent at a higher O2/coal ratio, whereas the chlorine and fluorine are enriched in the remaining char, and the extent of the enrichment at the latter stage of gasification is larger with the fluorine. The XPS measurements of the chars reveal the presence of the broad F 1 s peak, which can cover a wide range of binding energies attributable to inorganic and organic fluorine. The halogen enrichment during gasification is discussed in terms of secondary reactions of HCl and HF with char. 相似文献
10.
Guimes Rodrigues Filho Leandra Cardoso Toledo Daniel Alves Cerqueira Rosana Maria Nascimento de Assunção Carla da Silva Meireles Harumi Otaguro Sizue Ota Rogero Ademar Benévolo Lugão 《Polymer Bulletin》2007,59(1):73-81
Summary In this article, cellulose acetate produced through the homogeneous acetylation of sugar cane bagasse cellulose was used to
produce membranes, using poly(ethyleneglycol) 600 (PEG 600) as an admixture. The membranes were characterized using water
flux measurements (Payne’s cup), differential scanning calorimetry (DSC) and neutral red uptake (cytotoxicity). The results
showed that PEG 600 acts as a crystallinity inductor and/or pore former in the cellulose acetate matrix. The induction of
crystallinity is important for this system since it had not been reported on the literature yet. The results also demonstrated
that the studied membranes present a nontoxic behavior. 相似文献