全文获取类型
收费全文 | 453篇 |
免费 | 13篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 14篇 |
综合类 | 1篇 |
化学工业 | 172篇 |
金属工艺 | 8篇 |
机械仪表 | 9篇 |
建筑科学 | 4篇 |
能源动力 | 31篇 |
轻工业 | 36篇 |
无线电 | 27篇 |
一般工业技术 | 102篇 |
冶金工业 | 21篇 |
原子能技术 | 7篇 |
自动化技术 | 36篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 10篇 |
2021年 | 11篇 |
2020年 | 5篇 |
2019年 | 8篇 |
2018年 | 7篇 |
2017年 | 5篇 |
2016年 | 13篇 |
2015年 | 8篇 |
2014年 | 18篇 |
2013年 | 25篇 |
2012年 | 25篇 |
2011年 | 33篇 |
2010年 | 27篇 |
2009年 | 31篇 |
2008年 | 27篇 |
2007年 | 31篇 |
2006年 | 17篇 |
2005年 | 20篇 |
2004年 | 17篇 |
2003年 | 18篇 |
2002年 | 14篇 |
2001年 | 12篇 |
2000年 | 13篇 |
1999年 | 7篇 |
1998年 | 13篇 |
1997年 | 9篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 1篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1975年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有468条查询结果,搜索用时 15 毫秒
1.
Shouko Nishida Masaya Shibano Hiroshi Kamitakahara Toshiyuki Takano 《International journal of molecular sciences》2015,16(12):29093-29102
We recently observed that the decanoylation of N-phenylthiocarbamoyl chitosan (2) with a mixture of decanoic anhydride and pyridine at 60 °C for 24 h afforded N,N-(decanoyl)phenythiocarbamoyl-/2-isothiocynato chitosan decanoate (3b) rather than the expected product N,N-(decanoyl)phenylthiocarbamoyl chitosan decanoate (3a). This result suggested that some of the N,N-(decanoyl)phenylthiocarmbamoyl groups had been converted to isothiocyanate groups during the decanoylation process. The subsequent reaction of compound 3b with aniline gave N,N-(decanoyl)phenylthiocarbamoyl/N-phenylthiocarbamoyl chitosan decanoate (4) in high yield. A solution of compound 4 in CHCl3 was then added to a solution of copper decanoate (5) in the same solvent, and the resulting mixture was cast onto a glass plate to give a cast film. The film was annealed at 200 °C in an oven to give a greenish film, which showed good near-infrared absorption characteristic in the range of 800–2200 nm. 相似文献
2.
3.
Masaya Takahashi Akinori Nakata Takashi Haratani Yasutaka Ogawa Heihachiro Arito 《Ergonomics》2004,47(9):1003-1013
A worksite study was conducted to examine whether a 15-min nap during a post-lunch rest period would affect subsequent alertness, performance, and nocturnal sleep in eight factory workers under a 3-week protocol. Subjects were asked to take the nap at 12:30 h on a reclining chair during the nap week, and to remain awake during the no-nap week. The order of these 2 weeks was counterbalanced between the subjects. During the third, follow-up week, each subject determined whether or not she/he would nap. Alertness on the job and nocturnal sleep were assessed using a sleep diary. Wrist activity was also recorded during sleep at night. Choice reaction time task (RT) was performed at 10:00 and 15:00 h every day of the nap week and every other day of the no-nap and follow-up weeks. Perceived alertness was significantly higher in the afternoon after nap than after no nap at the end of the week. Similar effects were observed during the follow-up week where almost half of the subjects napped. No significant differences between the three weeks were found for RT performance or nocturnal sleep. Workers' attitudes toward the nap were favourable. Although further intervention research is required, our results suggest that post-lunch napping may have the potential to promote daytime alertness at work. 相似文献
4.
5.
Tetsuya Ikuta Yuki Miyanami Hayato Iwamoto Takayoshi Shimura Kiyoshi Yasutake 《Science and Technology of Advanced Materials》2007,8(3):142-145
Selective epitaxial Si with a high arsenic concentration of 2.2×1019 atoms/cm3 was deposited at a high growth rate of 3.3 nm/min under atmospheric pressure. It was confirmed that this method had excellent selectivity and produced films having good crystalline quality, abrupt dopant profiles at the interfaces, and smooth surfaces. The growth mechanism is discussed in terms of the relationship between the effects of arsenic surface segregation and etching by hydrogen chloride. 相似文献
6.
Masakazu Anpo Shinya Higashimoto Masaya Matsuoka Nurbosyn Zhanpeisov Yasushi Shioya Stanislaw Dzwigaj Michel Che 《Catalysis Today》2003,78(1-4):211-217
V-silicalite catalysts (VS-1 and VS-2) prepared by hydrothermal synthesis have been studied by ESR, XAFS (XANES and EXAFS) and photoluminescence spectroscopy. The in situ characterization of these V-silicalites shows that vanadium is present within the zeolitic framework as a highly dispersed tetrahedrally coordinated V-oxides, VO4 unit, having a short V=O bond length. Photoluminescence spectroscopy in static and dynamic mode, as well as XAFS studies allow to detect in the V-silicalites different V species than that present in V-HMS or V/SiO2, in terms of V=O bond length, vibrational energy,
bond angle and lifetime of the excited triplet state. It is suggested that the combined contribution of the neighboring Si---OH group attached to the VO4 unit and the zeolitic rigid framework structure of V-silicalites cause a more significant and pronounced effect on the chemical properties of the VO4 unit than the flexible structure of V-HMS or V/SiO2. Moreover, the dynamic quenching of the phosphorescence by the addition of reactant molecules such as NO or propane indicates that the V species in the excited triplet state can be expected to be the active sites for the photocatalytic reactions. 相似文献
7.
Kazuo Fujiura Yasutake Ohishi Shigeki Sakaguchi Yukio Terunuma 《Journal of the American Ceramic Society》1989,72(8):1368-1372
A technique for synthesizing ultra-high-purity ZrF4 using chemical vapor deposition in a ZrBr4 –HF system is developed and a purification mechanism is clarified. The Fe concentration in ZrF4 is evaluated at less than 10 ppb based on analysis of the transmission loss spectrum of a fiber prepared using synthesized ZrF4 . Purification is achieved mainly in a sublimation process of ZrBr4 , and purification efficiency is determined by sublimation temperature and activity of impurities in ZrBr4 . The concentration of transition-metal impurities in ZrF4 , synthesized by chemical vapor deposition in the ZrBr4 –HF system, is expected to be less than 1 ppb. 相似文献
8.
Kikuo Maekawa Makoto Yamazaki Toshinobu Ogiso Takehiko Maruyama Hideki Ogura Wakako Kashino Hanae Koiso Masaya Yamaguchi Makiro Tanaka Yasuharu Den 《Language Resources and Evaluation》2014,48(2):345-371
The balanced corpus of contemporary written Japanese (BCCWJ) is Japan’s first 100 million words balanced corpus. It consists of three subcorpora (publication subcorpus, library subcorpus, and special-purpose subcorpus) and covers a wide range of text registers including books in general, magazines, newspapers, governmental white papers, best-selling books, an internet bulletin-board, a blog, school textbooks, minutes of the national diet, publicity newsletters of local governments, laws, and poetry verses. A random sampling technique is utilized whenever possible in order to maximize the representativeness of the corpus. The corpus is annotated in terms of dual POS analysis, document structure, and bibliographical information. The BCCWJ is currently accessible in three different ways including Chunagon a web-based interface to the dual POS analysis data. Lastly, results of some pilot evaluation of the corpus with respect to the textual diversity are reported. The analyses include POS distribution, word-class distribution, entropy of orthography, sentence length, and variation of the adjective predicate. High textual diversity is observed in all these analyses. 相似文献
9.
Masaya Ibe Sinue Gmez Kinga A. Malinger Paul Fanson Steven L. Suib 《Applied catalysis. B, Environmental》2007,69(3-4):235-239
The activity of NOx storage-reduction (NSR) catalysts is greatly reduced by sulfur poisoning, caused by the SO2 present in the exhaust stream. Desorption of sulfur species from poisoned NSR catalysts occurs at temperatures in excess of 600 °C using reducing atmospheres and conventional heating. In this work, microwave (MW) heating has been used to promote desulfurization of poisoned NSR catalysts. The experiments were carried out by heating the catalyst with MW radiation and using hydrogen as the reducing gas. Desorption of H2S at 200 °C was observed. Desorption at even lower temperatures (150 °C) was observed when water was introduced to the system. In the presence of water, sulfur species desorbed as both H2S and SO2. An overall reduction of sulfur species of about 60% was obtained. The use of MW heating proves to be an efficient way to achieve regeneration of poisoned NSR catalysts. 相似文献
10.
Yuji Tatemoto Masaya Tsunekawa Shuji Yano Takenari Takeshita Katsuji Noda 《Chemical engineering science》2007,62(8):2187-2197
A relatively large wet material was immersed in a fluidized bed of hygroscopic porous particle (silica gel beads) under reduced pressure. And then the drying characteristics were compared with those in the case of inert particle (glass beads). The comparison of drying characteristics is performed experimentally and theoretically. In calculation, the water transfer from the sample to the fluidized bed was considered. The calculation results are in good agreement with the experimental data. The effects of the operational conditions (the pressure in the drying chamber and the temperature of the drying gas) on the drying characteristics were also examined in both fluidizing particles.The drying finishes earlier in the case of hygroscopic porous particle than in the case of inert particle regardless of pressure in the drying chamber, since the water transfer from the sample facilitates the drying in the case of hygroscopic porous particles. The temperature decrement in drying appears in the case of inert particle. This phenomenon is also observed in the case of hygroscopic porous particle, but the decrement degree of the temperature is much smaller than that in the case of inert particle. The difference of the minimum temperature in the sample in drying between the cases of hygroscopic porous particle and inert particle is very slight for different pressures in the drying chamber. 相似文献