全文获取类型
收费全文 | 226篇 |
免费 | 8篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 13篇 |
化学工业 | 82篇 |
金属工艺 | 19篇 |
建筑科学 | 4篇 |
能源动力 | 6篇 |
轻工业 | 6篇 |
无线电 | 11篇 |
一般工业技术 | 53篇 |
冶金工业 | 28篇 |
原子能技术 | 4篇 |
自动化技术 | 9篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 11篇 |
2012年 | 7篇 |
2011年 | 22篇 |
2010年 | 13篇 |
2009年 | 9篇 |
2008年 | 11篇 |
2007年 | 17篇 |
2006年 | 4篇 |
2005年 | 6篇 |
2004年 | 8篇 |
2003年 | 11篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 7篇 |
1998年 | 16篇 |
1997年 | 8篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1976年 | 3篇 |
排序方式: 共有235条查询结果,搜索用时 15 毫秒
51.
In this study, we utilized Mg-Al layered double hydroxide (Mg-Al LDH) modified by intercalation with three aromatic sulfonates—2,7-naphthalene disulfonate (2,7-NDS2−), benzenesulfonate (BS−), and benzenedisulfonate (BDS2−)—for the uptake of two aromatics—1,3-dinitrobenzene (DNB) and anisole (AS)—from aqueous solution and determined the effect of the aromatic sulfonates on the uptake of these aromatics. We found that the electron-rich aromatic ring of the intercalated aromatic sulfonates such as 2,7-NDS2− undergoes strong π-π stacking interactions with the electron-poorer benzene ring of DNB in aqueous solution, and these interactions result in a higher uptake of DNB by the modified Mg-Al LDHs. In contrast, the electron-poor aromatic ring of the aromatic sulfonates such as BDS2− undergoes weak π-π stacking interactions with the electron-poorer benzene ring of DNB, and these interactions result in a lower uptake of DNB by the modified Mg-Al LDHs. 相似文献
52.
Abe K Nakamura K Arao T Sakurai Y Nakano A Suginuma C Tawarada K Sasaki K 《Journal of the science of food and agriculture》2011,91(8):1392-1397
BACKGROUND: A simple and quick on‐site test for trace levels of cadmium (Cd) in food is needed because of the human toxicity of this heavy metal. We developed an immunochromatography kit which uses the antigen‐antibody complex reaction between the Cd–ethylenediaminetetraacetic acid (Cd–EDTA) complex and an anti‐Cd–EDTA antibody. We previously reported the successful use of this kit to determine Cd concentrations in brown rice with respect to the international standard: 0.4 mg kg?1. Here, we measured, using this immunochromatography kit, Cd concentrations in crops with lower international standards than rice. RESULTS: Cadmium extracted with 0.1 mol L?1 HCl from wheat grain and fresh eggplant was purified sufficiently using an ion‐exchange column treatment. Appropriate HCl extraction rates and dilution rates for the column eluate were selected; Cd concentrations in wheat grain and fresh eggplant were determined successfully by immunochromatography with respect to the international standards of 0.2 mg kg?1 and 0.05 mg kg?1 fresh weight, respectively. CONCLUSION: Approximate Cd concentrations in wheat grain and fresh eggplant can be monitored easily and quickly by this method at locations where facilities for acid digestion and precision analysis are not available. Copyright © 2011 Society of Chemical Industry 相似文献
53.
Tomohito Kameda Masahiko Ono Guido Grause Tadaaki Mizoguchi Toshiaki Yoshioka 《Journal of Polymer Research》2011,18(5):945-947
Poly(vinyl chloride) (PVC) modified in different solvents by nucleophilic substitution with thiocyanate was exposed to Gram-negative
bacteria of the strain Staphylococcus capitis. All modified pieces reduced the adhesion of bacteria by between 67 and 79%. More important for the bacteria suppression
than the substitution rate was the ratio between thiocyanate and isothiocyanate groups. The best result was obtained with
PVC modified in tetrahydrofuran/dimethylsulfoxide, containing only antibacterial active isothiocyanate groups, while inactive
thiocyanate groups were absent. 相似文献
54.
Hye Ryeon Lee Masakoto Kanezashi Yoshihiro Shimomura Tomohisa Yoshioka Toshinori Tsuru 《American Institute of Chemical Engineers》2011,57(10):2755-2765
Organic/inorganic hybrid silica membranes were prepared from 1,1,3,3‐tetraethoxy‐1,3‐dimethyl disiloxane (TEDMDS) by the sol‐gel technique with firing at 300–550°C in N2. TEDMDS‐derived silica membranes showed high H2 permeance (0.3–1.1 × 10?6 mol m?2 s?1 Pa?1) with low H2/N2 (~10) and high H2/SF6 (~1200) perm‐selectivity, confirming successful tuning of micropore sizes larger than TEOS‐derived silica membranes. TEDMDS‐derived silica membranes prepared at 550°C in N2 increased gas permeances as well as pore sizes after air exposure at 450°C. TEDMDS had an advantage in tuning pore size by the “template” and “spacer” techniques, due to the pyrolysis of methyl groups in air and Si? O? Si bonding, respectively. For pore size evaluation of microporous membranes, normalized Knudsen‐based permeance, which was proposed based on the gas translation model and verified with permeance of zeolite membranes, reveals that pore sizes of TEDMDS membranes were successfully tuned in the range of 0.6–1.0 nm. © 2011 American Institute of Chemical Engineers AIChE J, 2011 相似文献
55.
Thermal and electrical conduction properties of vertically aligned carbon nanotubes produced by water-assisted chemical vapor deposition 总被引:1,自引:0,他引:1
Atsuto Okamoto Itaru Gunjishima Takashi Inoue Megumi Akoshima Hidenori Miyagawa Tomohito Nakano Tetsuya Baba Masaki Tanemura Gendo Oomi 《Carbon》2011,(1):294-298
We present both thermal and electrical conduction properties of vertically aligned carbon nanotubes (VACNTs), synthesized by the water-assisted chemical vapor deposition method using Fe–Ti–O nanoparticles as catalyst. Thermal diffusivity and electrical resistance of VACNTs have been measured by the laser flash method and direct-current four-terminal method, respectively. The VACNTs are found to have thermal diffusivities of the same order as isotropic graphite and the electrical characteristics of semiconductors. The electrical resistance shows a T−1/4 temperature dependence, which implies that the conduction of electrons is dominated by 3D Mott variable range hopping. 相似文献
56.
The clusters of Fe, Ni, and Fe–Ni are investigated computationally using a density functional approach. The geometries of clusters are optimized under the constraint of well-defined point group symmetries at the UB3LYP/LanL2DZ level. The equilibrium geometries and binding energies are presented and discussed, together with natural populations and natural electron configurations. In addition, the binding energies of Fen−xNix clusters are found to generally decrease by successive substitutions of Ni atoms for Fe atoms. For Fen−xNix clusters, the comparisons on total energies between isomers indicate that Ni atoms energetically prefer clustering in the mixed Fe–Ni clusters. The calculations for Fen−xNix clusters show that the clustering leads to a segregation of Ni atoms from Fe atoms. 相似文献
57.
Noriyuki Hayashi Tetsuo Sugahara Shin‐Ichiro Tsuru Masanori Hara 《IEEJ Transactions on Electrical and Electronic Engineering》2006,1(2):194-206
A centrifugal method was used to fabricate large‐scale functionally graded materials (FGMs) from solid‐particles/viscous‐matrix mixtures at room temperature. The conventional simulation procedure of the centrifugal process was improved by considering the dependency of the viscosity η of the mixture on the packing fraction νp of particle, the effects of arbitrary shape of the actual fillers on η, the statistical dispersion of the diameters of the actual fillers, and the formation and growth of the fully packed layer (FPL) near the FGM bottom. The new simulation method was applied to three centrifugal processes employed for experimental FGM fabrications from alumina/epoxy mixtures. The numerical profiles of νp are in good agreement with the experimental ones regardless of the shapes of fillers and 'ponding viscosity of the solutions without fillers, the total amount of fillers loaded, and the centrifugal conditions. The saturating nature of νp near the far end of the FGM column is also simulated with reasonable precision. Finally, the manner in which the particles exert varying influences on the gradient of νp is demonstrated: the particles exhibit different movements depending on their size. On the basis of these results, the effectiveness of the new simulation method proposed is confirmed for the modeling of similar processes involved in the fabrication of FGMs from solid‐particles/viscous‐matrix mixtures by the centrifugal method. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
58.
A photocatalytic membrane reactor for gas-phase reactions using porous titanium oxide membranes 总被引:10,自引:0,他引:10
Toshinori Tsuru Takehiro Kan-no Tomohisa Yoshioka Masashi Asaeda 《Catalysis Today》2003,82(1-4):41-48
Photocatalytic membrane reactors using porous titanium oxide membranes having pore sizes of several nanometers were utilized for a gas-phase reaction of methanol. Air mixed with methanol (MeOH) vapor, the concentration of which was controlled in the range of 500–6000 ppm, was fed to the photocatalytic membrane reactor in the range of 50–500 cm3/min using several types of flow patterns. Photocatalysis with membrane permeation resulted in a large decomposition rate, compared to photocatalysis without membrane permeation. The characteristics of the reaction such as decomposition ratio of MeOH, the conversion of the decomposed MeOH to CO2 and H2O were found to be a function of the residence time in the reactor. The photocatalytic reaction was analyzed based on pseudo-first-order kinetics to ascertain its simplicity, and the fitted curves were found to be in a relatively good agreement with the experimental data. Apparent rate constants with and without membrane permeation were 2.5 and 1.5×10−6 m s−1, respectively, indicating that the performance of the photocatalytic reaction system with membrane permeation was enhanced. 相似文献
59.
Yoshinori Kitatsuji Masato Tsuru Tetsuya Takine Yuji Oie 《Telecommunication Systems》2008,37(1-3):97-108
In traffic engineering (TE), it is vital to take traffic characteristics of the flows into account in appropriately assigning the flows to multiple network paths to achieve better delay performance as a whole in order to effectively distribute traffic flows over the paths. This paper presents a novel traffic characteristic-aware flow assignment method to reduce the queuing delay in a fundamental case where two types of flows with distinct traffic characteristics (e.g., burstiness) are distributed into two paths. First, we extensively analyze the queuing delays in assigning flows in the manner of various combinations of flows in terms of minimizing the worst queuing delay among two paths and show that it is not easy to find the optimal flow assignment when the paths have different bandwidths. Second, we propose an on-line flow assignment method for the different-bandwidth paths and show that the numerical simulation with the method finds a nearly optimal flow assignment and outperforms up to 40% compared with the conventional path-bandwidth-based flow assignment. Our evaluation suggests that considering the traffic characteristics in the flow distribution over multiple paths significantly improves the delay performance when the flows have distinct characteristics. 相似文献
60.
Yasuhiko Ito Kiyoshi Tsuru Jun Oishi Yoshinori Miyazaki Teruo Kodama 《Journal of power sources》1985,16(1):75-82
An Li2CO3/Na2CO3/K2CO3 eutectic melt has been selected as an example of a molten-carbonate system and the suitability of a stabilized zirconia—air electrode as an oxide-ion concentration indicator for this melt has been confirmed.With this indicator, the dissociation constant of the reaction CO32? (?) = CO2(g) + O2? (?) in this melt has been determined to be Kd = PCO2 [O2?] = 4.03 × 10?3 Pa at 873 KReproducible measurements were obtained throughout the experiment and this method might find further application in the study of reactions related to the oxide ion in carbonate melts. 相似文献