全文获取类型
收费全文 | 1746篇 |
免费 | 10篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 7篇 |
综合类 | 2篇 |
化学工业 | 95篇 |
金属工艺 | 96篇 |
机械仪表 | 4篇 |
建筑科学 | 13篇 |
能源动力 | 27篇 |
轻工业 | 13篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 87篇 |
一般工业技术 | 124篇 |
冶金工业 | 1235篇 |
原子能技术 | 1篇 |
自动化技术 | 59篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 15篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 7篇 |
2016年 | 3篇 |
2014年 | 18篇 |
2013年 | 33篇 |
2012年 | 34篇 |
2011年 | 41篇 |
2010年 | 48篇 |
2009年 | 35篇 |
2008年 | 36篇 |
2007年 | 36篇 |
2006年 | 25篇 |
2005年 | 14篇 |
2004年 | 16篇 |
2003年 | 14篇 |
2002年 | 22篇 |
2001年 | 16篇 |
2000年 | 21篇 |
1999年 | 47篇 |
1998年 | 316篇 |
1997年 | 207篇 |
1996年 | 136篇 |
1995年 | 70篇 |
1994年 | 74篇 |
1993年 | 73篇 |
1992年 | 27篇 |
1991年 | 21篇 |
1990年 | 14篇 |
1989年 | 29篇 |
1988年 | 26篇 |
1987年 | 28篇 |
1986年 | 23篇 |
1985年 | 30篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1980年 | 17篇 |
1979年 | 3篇 |
1978年 | 7篇 |
1977年 | 41篇 |
1976年 | 90篇 |
1975年 | 2篇 |
1955年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有1765条查询结果,搜索用时 15 毫秒
61.
Ozonation of Pyrolytic Aqueous Phase: Changes in the Content of Phenolic Compounds and Color 下载免费PDF全文
Shi‐Shen Liaw Oselys Rodriguez Justo Victor Haber Perez Shuai Zhou Manuel Garcia‐Perez 《化学工程与技术》2016,39(10):1828-1834
Ozonation on the phenols present in pyrolytic aqueous phases attained from biomass thermochemical conversion was evaluated. During ozonation, the dark color of original samples was found to decrease as a function of ozonation time. The oxidation kinetics of phenols was quantified by a method based on the color changes of samples. The oxidation profiles showed different behaviors and in some cases the phenols presented a positive correlation with the relative R color parameter, except eugenol, syringol, and vanillin which were markedly different. Finally, the color changes observed seem to be associated with the changes in the overall content of phenols and with the change in the molecular weight of the heavy fractions that include lignin oligomers. 相似文献
62.
Yun‐Hsuan Huang Shu‐Hsien Huang Wei‐Chi Chao Chi‐Lan Li Yun‐Ying Hsieh Wei‐Song Hung Der‐Jang Liaw Chien‐Chieh Hu Kueir‐Rarn Lee Juin‐Yih Lai 《Polymer International》2014,63(8):1478-1486
To improve the pervaporation performance in separating an aqueous ethanol solution, polyamide thin‐film composite (TFC) membranes (m‐tolidine‐H‐TMC/mPAN) were prepared through the interfacial polymerization reaction between trimesoyl chloride (TMC) and 2,2'‐dimethylbenzidine hydrochloride (m‐tolidine‐H) on the surface of a modified polyacrylonitrile (mPAN) membrane. The effects of the feed ethanol concentration on the pervaporation performance and the durability of m‐tolidine‐H‐TMC/mPAN TFC membranes were investigated. To choose the optimal mPAN membrane as the TFC substrate, the effect of hydrolysis time on the chemical properties and separation performance of an mPAN substrate was also studied. An appropriate hydrolysis time of 15 min was chosen to obtain the mPAN substrate due to the corresponding high permeation flux. The m‐tolidine‐H‐TMC/mPAN TFC membrane exhibited a high pervaporation performance for ethanol dehydration. A positron annihilation lifetime spectroscopy experiment was used to estimate the mean free‐volume radius of the m‐tolidine‐H‐TMC polyamide selective layer, which lay between the radii of the water and ethanol molecules. © 2013 Society of Chemical Industry 相似文献
63.
Yu-Hao Lee Tsun-Cheng Wu Chao-Wu Liaw Ten-Chin Wen Shih-Wei Feng Jey-Jau Lee Yao-Ting Wu Tzung-Fang Guo 《Organic Electronics》2013,14(4):1064-1072
This work studies a series of fluorescent materials, benzo[k]fluoranthene-based linear acenes, and uses these materials directly as the non-doped active layer to fabricate deep blue- to green-emissive organic light emitting diodes (OLEDs). Experimental results indicate that benzo[k]fluoranthene-based linear acenes with different substituents in pristine films have a wide range and strong intensity of the luminescence spectra. The substituents of benzo[k]fluoranthene derivatives modulate the lifetime of the excited state and PL spectra of excitonic, excimer or both emissions in the solid state. Controls of emission spectra are exploited in fabricating high-performance non-doped deep blue to green OLEDs with electroluminescence in the deep blue region (420–460 nm), green region (480–580 nm) or both (430–580 nm). 相似文献
64.
65.
Yoshihiko Yokoyama D. Gary Harlow Peter K. Liaw Akihisa Inoue 《Metallurgical and Materials Transactions A》2010,41(7):1780-1786
High fatigue strength is one of the important factors that facilitates the industrial usage of bulk metallic glasses (BMGs).
Fatigue data were analyzed using the Weibull probability models for BMGs produced with different casting processes in order
to study the reliability of fatigue strengths of cast glassy alloys. The fatigue data of tilt-cast and high-pressure-cast
BMGs can be explained by a three-parameter Weibull cumulative distribution function (cdf) and a mixture model of two-parameter
Weibull cdfs, respectively. We conclude that the cast defects, which reduce fatigue strength, should be eliminated in order
to realize a high reliability of fatigue strengths. 相似文献
66.
D. Y. Cong Y. D. Wang X. Zhao L. Zuo R. Lin Peng P. Zetterström P. K. Liaw 《Metallurgical and Materials Transactions A》2006,37(5):1397-1403
Three ferromagnetic shape-memory alloys with the chemical compositions of Ni53Mn25Ga22, Ni48Mn30Ga22, and Ni48Mn25Ga22Co5 were prepared by the induction-melting and hot-forging process. The crystal structures were investigated by the neutron powder
diffraction technique, showing that Ni53Mn25Ga22 and Ni48Mn25Ga22Co5 have a tetragonal, 14/mmm martensitic structure at room temperature, while Ni48Mn30Ga22 has a cubic, L21 austenitic structure at room temperature. The development of textures in the hot-forged samples shows the in-plane plastic
flow anisotropy from the measured pole figures by means of the neutron diffraction technique. Significant texture changes
were observed for the Ni48Mn25Ga22Co5 alloy after room temperature deformation, which is due to the deformation-induced rearrangements of martensitic variants.
An excellent shape-memory effect (SME) with a recovery ratio of 74 pct was reported in this Ni48Mn25Ga22Co5 polycrystalline alloy after annealing above the martensitic transformation temperature, and the “shape-memory” influence
also occurs in the distributions of grain orientations. 相似文献
67.
68.
WJ Fairbrother MA Champe HW Christinger BA Keyt MA Starovasnik 《Canadian Metallurgical Quarterly》1998,6(5):637-648
Tricorn protease was previously described as the core enzyme of a modular proteolytic system displaying multicatalytic activity. Here we elucidate the mode of cooperation between Tricorn and its interacting factors, and we identify two additional factors, F2 and F3, closely related aminopeptidases of 89 kDa. In conjunction with these three factors, Tricorn degrades oligopeptides in a sequential manner, yielding free amino acids. We have been able to reconstitute a proteolytic pathway comprising the proteasome, Tricorn, and its interacting factors, F1, F2, and F3, which converts proteins efficiently into amino acids. Therefore, it is quite likely that Tricorn also acts in vivo downstream of the proteasome and, in cooperation with its interacting factors, completes protein catabolic pathways. 相似文献
69.
70.
Systemic vasculopathy in patients with neurofibromatosis type 1 is rare. We describe a case of unusual cerebral and renal involvement in a young, 29-year-old patient, who died of a cerebral ischemic attack one year after our observation. 相似文献