全文获取类型
收费全文 | 511篇 |
免费 | 11篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 30篇 |
化学工业 | 193篇 |
金属工艺 | 16篇 |
机械仪表 | 11篇 |
建筑科学 | 4篇 |
能源动力 | 28篇 |
轻工业 | 18篇 |
水利工程 | 1篇 |
无线电 | 32篇 |
一般工业技术 | 108篇 |
冶金工业 | 27篇 |
原子能技术 | 17篇 |
自动化技术 | 38篇 |
出版年
2022年 | 10篇 |
2021年 | 10篇 |
2020年 | 7篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 6篇 |
2016年 | 5篇 |
2015年 | 4篇 |
2014年 | 14篇 |
2013年 | 23篇 |
2012年 | 18篇 |
2011年 | 32篇 |
2010年 | 18篇 |
2009年 | 25篇 |
2008年 | 28篇 |
2007年 | 20篇 |
2006年 | 22篇 |
2005年 | 26篇 |
2004年 | 14篇 |
2003年 | 17篇 |
2002年 | 12篇 |
2001年 | 11篇 |
2000年 | 8篇 |
1999年 | 11篇 |
1998年 | 16篇 |
1997年 | 14篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 13篇 |
1993年 | 11篇 |
1992年 | 6篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 11篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 11篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 7篇 |
1980年 | 2篇 |
1979年 | 6篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1963年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有523条查询结果,搜索用时 171 毫秒
1.
2.
Toshimitsu Suzuki Osamu Yamada Yasuhiko Takahashi Yoshihisa Watanabe 《Fuel Processing Technology》1985,10(1):33-43
Hydroliquefaction of low-sulfur Australian coals (Wandoan and Yallourn) was studied using iron carbonyl complexes as catalyst. The addition of Fe(CO)5 (2.8 wt% Fe of coal) increased coal conversion from 48.6 to 85.2% for Wandoan coal, and from 36.7 to 69.7% for Yallourn coal in 1-methylnaphthalene at 425°C under an initial hydrogen pressure of 50 kg cm?2. When molecular sulfur was added to iron carbonyls (Fe(CO)5, Fe2(CO)9 and Fe3(CO)12), higher coal converions ( > 92%) and higher oil yields (>46%) were obtained, along with an increase in the amount of hydrogen transferred to coal from the gas phase (0.2 to 2.8%, d.a.f. coal basis). In the liquefaction studies using a hydrogen donor solvent, tetralin, Fe(CO)5S catalyst increased the amount of hydrogen absorbed from the gaseous phase and decreased the amount of naphthalene dehydrogenated from tetralin. The direct hydrogen transfer reaction from molecular hydrogen to coal fragment radicals seems to be a major reaction pathway. Organic sulfur compounds, dimethyldisulfide and benzothiophene, and inorganic FeS2 and NiS were found to be good sulfur sources to Fe(CO)5. From X-ray diffraction analyses of liquefaction residues, it is concluded that Fe(CO)5 was converted into pyrrhotite (Fe1?xS) when sulfur was present, but into Fe3O4 in the absence of sulfur. 相似文献
3.
Moon Ho Lee Jong Oh Park Yasuhiko Yasuda 《Multidimensional Systems and Signal Processing》1990,1(4):389-398
in this paper, simple 1-D and 2-D systolic array for realizing the discrete cosine transform (DCT) based on the discrete Fourier transform (DFT) fo an input sequence are presented. The proposed arrays are obtained by a simple modified DFT (MDFT) and an inverse DFT (IDFT) version of the Goertzel algorithm combined with Kung's approach. The 1-D array requiresN cells, one multiplier and takesN clock cycles to produce a completeN-point DCT. The 2-D array takes N clock cycles, faster than the 1-D array, but the area complexity is larger. A continuous flow of input data is allowed and no idle time is required between the input sequences. 相似文献
4.
Yuya Hattori Michiyo Suzuki Zu Soh Yasuhiko Kobayashi Toshio Tsuji 《Artificial Life and Robotics》2012,17(2):173-179
The pharyngeal pumping motion to send food to the bowel is a rhythmic movement in Caenorhabditis elegans. This paper proposes a simulation-based approach to investigate the mechanisms of rhythm phenomena in the pharyngeal pumping motion. To conduct the simulations, first, we developed a pharyngeal muscle model including 29 cell models which simulate the activity of each cell as a membrane potential based on FitzHugh-Nagumo equations. Then, to compare the response of the model with that of C. elegans, we calculated the electropharyngeogram (EPG), which represents the electrophysiological responses of the pharyngeal cells, using the simulated membrane potentials. The results confirmed that our model could generate the EPG similar to that measured from C. elegans. We proposed a computer simulation of the pumping motion to investigate the mechanisms of rhythm phenomena in living organisms. 相似文献
5.
Yasuhiko H. Mori Takehiro Nosoko Atsushi Mikami Tetsuya Ohyama 《Chemical Engineering Communications》1990,92(1):95-102
The shape of interfaces formed by the contact of two liquid phases, immiscible with each other, and a gaseous phase can be predicted on the condition that the tension to work at each interface is known with a sufficient accuracy. In general, interfacial tension data available are not so accurate, however, as to be useful as they are in predicting the shape of interfaces, particularly when the spreading coefficient of either liquid (liquid 1) on the other (liquid 2) has a negative value of a small magnitude. Presented in this note is a simple method to rectify the interfacial tension data, with the aid of a measurement of the radius of a lens of liquid 1 of a known volume placed on the horizontal surface of liquid 2, and thereby make them usable for predicting interfacial geometries. The method is tested by applying it to benzene/water and n-pentane/water systems. 相似文献
6.
Alain A Vertès Masayuki Inui Hideaki Yukawa 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2007,82(8):693-697
The challenges of implementing biorefineries on a global scale include socioeconomic, financial, and technological constraints. In particular, the development of biorefineries is tightly linked to the continued availability of fermentation raw materials. These constraints can be relaxed by the use of diverse raw materials, while advances that confer higher flexibility would enable biotechnological plant managers to swiftly react to volatile markets. In conventional processes, Saccharomyces cerevisiae grows on a relatively limited range of substrates, and produces only a single product—ethanol. Given the observed maturity of the S. cerevisiae fermentation technology, alternatives to baker's yeast may be needed to tip the economic balance in favour of biotechnological ethanol. These alternative fermentation technologies may allow a greater diversity of substrates to be used to produce an individually tailored mix of ethanol and other chemicals. Copyright © 2007 Society of Chemical Industry 相似文献
7.
Keiji Mimura Susumu Yukawa Yoshio Mori Kazuya Okada Masatoshi Mune Osamu Nishikawa Akira Hibino Miyahiko Sonobe Tetuya Goto Hiroshi Nomoto 《Lipids》1991,26(12):1102-1107
We investigated the effect of platelet-activating factor (PAF) and of the PAF specific antagonist CV-6209 on plasma lipid
metabolism, and particularly on post-heparin plasma lipolytic activity in male Wistar rats. Lipoprotein lipase (LPL) activity
was enhanced by intravenous injection of PAF before intravenous injection of heparin when the PAF dose was low (0.2 μg/kg).
PAF activated hepatic triacylglycerol lipase (HTGL) activity dose-dependently. Plasma triacylglycerols (TG) significantly
decreased with the activation of LPL and/or HTGL. Plasma total cholesterol (TC) and phospholipid (PL) levels decreased at
a low dose of PAF (0.2 μg/kg), but increased when higher doses were used. The PAF antagonist CV-6209 partially reversed the
PAF induced effects on HTGL, TC and PL.
Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl
Ether Lipids, Tokyo, Japan, May 1989. 相似文献
8.
Electrocodeposition of Sm and Co on a Cu substrate was investigated in a molten LiCl-KCl-SmCl3 (0.5 mol.%)-CoCl2 (0.1 mol.%) system at 723 K. Phase of the deposited Sm-Co alloys could be controlled by electrolysis potential. SmCo3 was formed on a Cu substrate by potentiostatic electrolysis in the potential range of 0.20-0.90 V (vs. Li+/Li). Sm2Co17 was obtained in the potential range of 0.90-1.50 V. 相似文献
9.
The proportion of non-conforming items has been traditionally utilised as an evaluation criterion for quality of items. However, the proportion of non-conforming items is not necessarily useful as a proper evaluation criterion for controlling high-quality manufacturing in recent years. Accordingly, in order to achieve further quality improvement and innovation, more careful quality evaluation has been required newly. Then, a concept of quality loss in the Taguchi methods has been devised as a severe criterion of quality evaluation. Hereby, a variable single sampling plan having desired operating characteristics (OCs) indexed by quality loss has been proposed in the area of statistical quality control. By the way, the most economical sampling inspection in the average sample number (ASN) is the sequential sampling plan based on the Wald’s sequential probability ratio test. Then, from the viewpoint of cost reduction, we discuss a variable sequential sampling plan having desired OC indexed by quality loss with the aim of expansion of the utility of variable sampling plan for quality loss. As the result, the design procedure of the sequential sampling plan for satisfying some required design conditions indexed by quality loss is provided. In addition, the effectiveness of the proposed sequential sampling plan is verified through some numerical examples. 相似文献
10.
Yukawa M. de Lamare R.C. Sampaio-Neto R. 《IEEE transactions on audio, speech, and language processing》2008,16(4):696-710
This paper presents a new approach to efficient acoustic echo cancellation (AEC) based on reduced-rank adaptive filtering equipped with selective-decimation and adaptive interpolation. We propose a novel structure of an AEC scheme that jointly optimizes an interpolation filter, a decimation unit, and a reduced-rank filter. With a practical choice of parameters in AEC, the total computational complexity of the proposed reduced-rank scheme with the normalized least mean square (NLMS) algorithm is approximately half of that of the full-rank NLMS algorithm. We discuss the convergence properties of the proposed scheme and present a convergence condition. First, we examine the performance of the proposed scheme in a single-talk situation with an error-minimization criterion adopted in the decimation selection. Second, we investigate the potential of the proposed scheme in a double-talk situation by employing an ideal decimation selection. In addition to mean squared error (MSE) and power spectrum analysis of the echo estimation error, subjective assessments based on absolute category rating are performed, and the results demonstrate that the proposed structure provides significant improvements compared to the full-rank NLMS algorithm. 相似文献