全文获取类型
收费全文 | 2264篇 |
免费 | 47篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 124篇 |
综合类 | 5篇 |
化学工业 | 515篇 |
金属工艺 | 52篇 |
机械仪表 | 31篇 |
建筑科学 | 28篇 |
能源动力 | 63篇 |
轻工业 | 170篇 |
水利工程 | 11篇 |
石油天然气 | 1篇 |
无线电 | 237篇 |
一般工业技术 | 364篇 |
冶金工业 | 470篇 |
原子能技术 | 72篇 |
自动化技术 | 176篇 |
出版年
2023年 | 13篇 |
2022年 | 31篇 |
2021年 | 37篇 |
2020年 | 22篇 |
2019年 | 19篇 |
2018年 | 27篇 |
2017年 | 26篇 |
2016年 | 43篇 |
2015年 | 31篇 |
2014年 | 48篇 |
2013年 | 84篇 |
2012年 | 80篇 |
2011年 | 119篇 |
2010年 | 76篇 |
2009年 | 97篇 |
2008年 | 95篇 |
2007年 | 87篇 |
2006年 | 85篇 |
2005年 | 66篇 |
2004年 | 54篇 |
2003年 | 66篇 |
2002年 | 45篇 |
2001年 | 51篇 |
2000年 | 52篇 |
1999年 | 49篇 |
1998年 | 239篇 |
1997年 | 127篇 |
1996年 | 93篇 |
1995年 | 46篇 |
1994年 | 54篇 |
1993年 | 65篇 |
1992年 | 25篇 |
1991年 | 30篇 |
1990年 | 27篇 |
1989年 | 22篇 |
1988年 | 12篇 |
1987年 | 14篇 |
1986年 | 14篇 |
1985年 | 16篇 |
1984年 | 13篇 |
1983年 | 16篇 |
1982年 | 12篇 |
1981年 | 18篇 |
1980年 | 6篇 |
1979年 | 14篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1976年 | 13篇 |
1973年 | 7篇 |
1969年 | 3篇 |
排序方式: 共有2319条查询结果,搜索用时 15 毫秒
81.
Sayoko Shironita Tomoya Takasaki Takashi Kamegawa Kohsuke Mori Hiromi Yamashita 《Topics in Catalysis》2010,53(3-4):218-223
Using microwave-assisted deposition method the uniform and nano-sized platinum metal particles were prepared on the tetrahedrally coordinated Ti-oxide moieties isolated within the framework of mesoporous silica supports. The present nano-sized metal catalyst exhibited a higher activity for hydrogenation of nitrobenzene than the catalyst prepared by a conventional impregnation method. 相似文献
82.
V. Matolín M. Cabala I. Matolínov M. koda M. Vclav K.C. Prince T. Skla T. Mori H. Yoshikawa Y. Yamashita S. Ueda K. Kobayashi 《Fuel Cells》2010,10(1):139-144
The interaction of Pt with CeO2 layers was investigated by using photoelectron spectroscopy. Thirty‐nanometre‐thick Pt and Sn doped CeO2 layers were deposited simultaneously by rf‐magnetron sputtering on a Si(001) substrate and a carbon diffusion layer of a polymer membrane fuel cell by using a composite CeO2–Pt–Sn target. The laboratory XPS and synchrotron radiation soft X‐ray and hard X‐ray photoemission spectra showed the formation of cerium oxide with completely ionised Pt2+,4+ species, and with Pt4+ embedded in the film bulk. Hydrogen/air fuel cell activity measurements normalised to the amount of Pt used revealed high specific power of up to 5.4 × 104 mW mg–1 (Pt). The activity of these materials is explained by the strong activity of embedded Ptn+ cations. 相似文献
83.
Jin Nishikawa Kazuya Nakamura Mohammad Asadullah Tomohisa Miyazawa Kimio Kunimori Keiichi Tomishige 《Catalysis Today》2008,131(1-4):146-155
In the steam gasification of biomass, the additive effect of noble metals such as Pt, Pd, Rh and Ru to the Ni/CeO2/Al2O3 catalyst was investigated. Among these noble metals, the addition of Pt was most effective even when the loading amount of added Pt was as small as 0.01 wt.%. In addition, the catalyst characterization suggests the formation of the Pt–Ni alloy over the Pt/Ni/CeO2/Al2O3. 相似文献
84.
Atmospheric corrosion of steel proceeds under thin electrolyte film formed by rain and dew condensation followed by wet and dry cycles. It is said that rust layer formed on steel as a result of atmospheric corrosion strongly affects the corrosion behavior of steel. The effect of environmental corrosiveness on the formation process and structure of the rust layer is, however, not clear to date. In this study, in situ observation of the rusting process of a carbon steel covered with a thin film of Na2SO4 or NaCl solution was performed under a wet/dry repeating condition by X-ray diffraction spectroscopy with white X-rays obtained from synchrotron radiation. The present in situ experiments successfully detected initial process of the rust formation. In the early cycles, the rust constituents were not well crystallized yet, but the presence of Fe(OH)2 and Fe(OH)3 was confirmed. In the subsequent cycles, two different solutions resulted in difference in preferential phase of the rust constituents. α-FeOOH was preferentially formed in the case of the Na2SO4 solution film, whereas β-FeOOH appeared only under the NaCl solution film. 相似文献
85.
86.
87.
Toru Nakajima Kazuyoshi Shiba Kazuya Tamegaya Kiyokazu Tsukamoto 《Welding International》2013,27(10):752-758
Recently, the electron beam welders with high acceleration voltage (more than 100 kV) and high electrical power (more than 15 kW) have been reviewed the role of the high-energy electron beam density again, due to space or aircraft development or automobile industry desired high productivity and high accurate welding for saving energy. NEC group have supplied these electron beam welders. This time, the automatic alignment adjustment system of the electron beam orbit and the automatic adjustment system of filament current were developed and put to a practical use. As a result, the great effectiveness for the stability of welding quality was apparent. 相似文献
88.
Tetsuya Iida Dr. Yukihiro Itoh Yukari Takahashi Dr. Yasunobu Yamashita Dr. Takashi Kurohara Dr. Yuka Miyake Prof. Makoto Oba Prof. Takayoshi Suzuki 《ChemMedChem》2021,16(10):1609-1618
Lysine demethylase 5 C (KDM5C) controls epigenetic gene expression and is attracting great interest in the field of chemical epigenetics. KDM5C has emerged as a therapeutic target for anti-prostate cancer agents, and recently we identified triazole 1 as an inhibitor of KDM5C. Compound 1 exhibited highly potent KDM5C-inhibitory activity in in vitro enzyme assays, but did not show strong anticancer effects. Therefore, a different approach is needed for the development of anticancer agents targeting KDM5C. Here, we attempted to identify KDM5C degraders by focusing on a protein-knockdown strategy. Compound 3 b , which was designed based on compound 1 , degraded KDM5C and inhibited the growth of prostate cancer PC-3 cells more strongly than compound 1 . These findings suggest that KDM5C degraders are more effective as anticancer agents than compounds that only inhibit the catalytic activity of KDM5C. 相似文献
89.
Fabíola Azanha de Carvalho Amanda Aleixo Moreira André Luiz Martinez de Oliveira Fabio Yamashita 《应用聚合物科学杂志》2021,138(28):50667
Neat poly (lactic acid) (PLA) and PLA/cassava bagasse (CB) composites were used to produce seedling tubes by extrusion and injection molding. The tubes were buried in simulated soil, and their biodegradation was investigated by weight loss, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). After 180 days, the composites' biodegradation was higher than neat PLA material, and the higher the CB content, the higher the biodegradation, which caused fissures and voids in the material. The biodegradation of PLA/CB composites increased the phosphorus content in the soil after 180 days. Composites of PLA with CB, an abundant agro-industrial residue in Brazil, are promising because they can reduce the environmental impact due to CB's proper destination, and the composites' costs and biodegradation are faster than pure PLA material. Both the faster biodegradation of the tube and the higher P content are advantageous for seedling tubes. 相似文献
90.
Caroline Cagnin Bruno Matheus Simões Fábio Yamashita Gizilene Maria de Carvalho Maria Victória Eiras Grossmann 《Polymer Engineering and Science》2021,61(2):388-396
This work aims to develop hydrogel films of starch and carboxymethyl cellulose (CMC) crosslinked with sodium trimetaphosphate (STMP) and to characterize some of their properties. Starch and STMP (S/T), starch and CMC (S/C), and mixed (S/T/C) films were prepared by casting. The degree of substitution, morphology, swelling degree, FTIR, mechanical properties, and sorption isotherms were studied. Reticulated samples (S/T and S/T/C) showed the same degree of substitution (0.050 ± 0.001). All films presented homogeneous morphology, but the mixed film showed greater roughness. Crosslinking increased the swelling capacity of the mixed hydrogel at pH 7, although it remained decreased concerning the S/T hydrogel. However, this property was sensitive to pH variations. The mixed film (S/T/C) showed greater mechanical resistance. The casting process was efficient to produce hydrogel films of starch/CMC crosslinked with STMP and the general results demonstrated the advantages of the mixed hydrogel. 相似文献