全文获取类型
收费全文 | 640篇 |
免费 | 11篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 20篇 |
化学工业 | 139篇 |
金属工艺 | 19篇 |
机械仪表 | 15篇 |
建筑科学 | 13篇 |
矿业工程 | 1篇 |
能源动力 | 28篇 |
轻工业 | 61篇 |
水利工程 | 2篇 |
石油天然气 | 2篇 |
无线电 | 63篇 |
一般工业技术 | 125篇 |
冶金工业 | 122篇 |
原子能技术 | 9篇 |
自动化技术 | 34篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 6篇 |
2017年 | 8篇 |
2016年 | 9篇 |
2015年 | 7篇 |
2014年 | 19篇 |
2013年 | 32篇 |
2012年 | 21篇 |
2011年 | 36篇 |
2010年 | 21篇 |
2009年 | 28篇 |
2008年 | 33篇 |
2007年 | 28篇 |
2006年 | 20篇 |
2005年 | 18篇 |
2004年 | 20篇 |
2003年 | 13篇 |
2002年 | 15篇 |
2001年 | 11篇 |
2000年 | 7篇 |
1999年 | 18篇 |
1998年 | 42篇 |
1997年 | 34篇 |
1996年 | 25篇 |
1995年 | 17篇 |
1994年 | 16篇 |
1993年 | 14篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 9篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 14篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1976年 | 5篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有653条查询结果,搜索用时 15 毫秒
31.
This paper undertakes a time series analysis of the Japanese divorce rate using annual data over the period 1964–2006. One of the key innovations of the paper is to use court decisions on divorce disputes to construct an index that seeks to measure how the probability of success in a divorce suit has changed over time. The computed index suggests that if it is the culpable party lodging the divorce suit, the probability of the suit being successful has clearly increased over time. The probability of winning a divorce suit appears to be an important factor in explaining the long-run rise in the Japanese divorce rate. The divorce rate also appears to be counter-cyclical. 相似文献
32.
Xing-Zheng Wu Toshiaki Nakaoka Tomomi Inoue Haruo Inoue 《Sensors and actuators. A, Physical》2009,155(2):241-245
Optical sensing of materials movements across a plant surface with a probe beam is reported. It is based on monitoring of deflection of a probe beam passing through a vicinity of the plant surface. The deflection of the probe beam was caused by concentration gradients of chemical species involved in the materials moments in physiological activities of the plant. Typha angustifolia L. was used as a model plant. The beam deflection at different locations of both leaves and roots in respiration process were monitored and compared. It is found that deflection signals changed with time and locations. Experimental results showed that the beam deflection method could be used for noninvasive sensing and monitoring of materials movements across the plant surface. 相似文献
33.
This paper describes an approximate microstructural optimization using the ns-kriging (noise-resistant smoothed kriging) method for minimizing the maximum stochastic variation of homogenized elastic properties of a composite material caused by microscopic uncertainties of component materials. Since evaluation of a stochastic characteristic of a homogenized material property such as expectation or variance will involve a high computational cost and its results include inaccuracy in using the Monte Carlo simulation, an approximation-based optimization technique is useful for solving the optimization problem considering the multiscale stochastic problem. Especially, the ns-kriging will work well in case of using inaccurate data for an unknown objective function. In order to investigate applicability and effectiveness of the proposed ns-kriging based approach to the optimization problem, it is applied to the cross-sectional shape optimization of fiber in a unidirectional FRP. From the numerical results, validity and effectiveness of the proposed approach are confirmed. 相似文献
34.
K. Sakata K. Kato Y. Iwase H. Okada K. Ina Y. Machiguchi 《Journal of chemical ecology》1991,17(1):185-193
Phagostimulant activity of glycerolipids such as digalactosyldiacylglycerol (DGDG), 6-sulfoquinovosyldiacylglycerol (SQDG), phosphatidylcholine (PC), phosphatidylethanolamine (PE), etc., have been examined using the Avicel plate method for three kinds of marine herbivorous gastropods, the abaloneHaliotis discus, the turban shellTurbo cornutus, and the topshellOmphalius pfeifferi. DGDG showed strong activity for all the test animals. SQDG was much less active than the other glycerolipids for abalone. The turban shell and the top shell responded more or less sensitively to all tested glycerolipids at doses of 10–20g/sample zone.Chemical Studies on Phagostimulants for Marine Gastropods. Part VIII. For Part VII, see Sakata et al. (1988a). 相似文献
35.
36.
Y Takeshita T Watanabe T Sakata M Munakata H Ishibashi N Akaike 《Canadian Metallurgical Quarterly》1998,87(4):797-805
Insects are known to be useful in estimating the postmortem interval (PMI). Here several cases are reported which show that a wide range of applications in medicolegal questions and hygiene together or apart from estimating the PMI can be answered by use of forensic entomology techniques, including close observation of larval development. Case 1 describes how blowfly larvae fell from a putrefied corpse, hid, and finally emerged from pupae three months after disinfection and renovation. In case 2, the entomological state of the decomposed corpse of a heroin user is described. Case 3 deals with a single adult Protophormia terranovae found in the skull of a partially mummified woman. Case 4 reports the finding of Serratia marcescens bacteria in red Muscina stabulans pupae which were found on a 5-day-old corpse. In case 5, blowfly eggs on the corpse of another heroin user are interpreted as an indication of the decedent being laid outside at night after his death in a flat. Case 6 deals with the finding of Parasarcophaga argyrostoma, which in Cologne might be an indicator species which tells if a corpse was lying outside at least for some time. 相似文献
37.
The photovoltaic and dark electrical properties of hydrogenated amorphous silicon diodes were changed by forward bias carrier injection for several hours. These changes were similar to photoinduced (PI) changes previously reported, and this result supports previous explanations for PI changes. The differences between these two types of change are also discussed. 相似文献
38.
Somiya K Beyersdorf P Arai K Sato S Kawamura S Miyakawa O Kawazoe F Sakata S Sekido A Mio N 《Applied optics》2005,44(16):3179-3191
We report on our prototype experiment that uses a 4-m detuned resonant sideband extraction interferometer with suspended mirrors, which has almost the same configuration as the next-generation, gravitational-wave detectors. We have developed a new control scheme and have succeeded in the operation of such an interferometer with suspended mirrors for the first time ever as far as we know. We believe that this is the first such instrument that can see the radiation pressure signal enhancement, which can improve the sensitivity of next-generation gravitational-wave detectors. 相似文献
39.
Tajima T Sakata W Wada T Tsutsui A Nishimoto S Miyake M Takaguchi Y 《Advanced materials (Deerfield Beach, Fla.)》2011,23(48):5750-5754
A coaxial nanohybrid consisting of a single-walled carbon nanotube (SWCNT), fullerodendron, and SiO(2) shows high-efficiency light-driven hydrogen evolution from water. Upon visible light irradiation, SWCNT/fullerodendron/SiO(2) coaxial nanohybrid shows hydrogen evolution activity in the presence of methyl viologen (MV(2+)), benzyldihydronicotinamide (BNAH), and a colloidal polyvinyl alcohol(PVA)-Pt. 相似文献
40.
Ryo Yamauchi Tomomi Kinoshita Satoshi Iwamoto 《Journal of the American Oil Chemists' Society》2018,95(3):361-369
γ‐Tocopherol is one of the main constituents in vegetable oils and acts as an antioxidant by trapping lipid‐peroxyl radicals. This study reports reaction products of γ‐tocopherol with lipid‐peroxyl radicals formed by iron‐catalyzed decomposition of methyl linoleate hydroperoxides (MeLOOH) in toluene and methanol solutions. The products in toluene solution were tocored, methyl (8a‐dioxy‐γ‐tocopherone)‐epoxyoctadecenoates (γT‐OO‐epoxyMeL), methyl (8a‐dioxy‐γ‐tocopherone)‐octadecadienoates (γT‐OO‐MeL), γ‐tocopherol biphenyl dimer (γTBD), γ‐tocopherol diphenylether dimer (γTED), and adducts of γ‐tocopherol dimers with the MeLOOH‐derived peroxyl radicals (γTED‐OO‐epoxyMeL, γTBD‐OO‐MeL, and γTED‐OO‐MeL). The iron‐catalyzed reaction in toluene proceeded slowly, whereas the reaction in methanol was relatively fast. The reaction products in methanol were γT‐OO‐epoxyMeL and γTED‐OO‐epoxyMeL together with tocored, γTBD, and γTED. The results indicate that the iron‐catalyzed decomposition of MeLOOH in toluene produces both epoxyperoxyl and peroxyl radicals and that the decomposition in methanol yields only the epoxyperoxyl radicals. These peroxyl radicals could react with the 8a‐carbon‐centered radical of γ‐tocopherol or its dimers. 相似文献