全文获取类型
收费全文 | 498篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 18篇 |
综合类 | 1篇 |
化学工业 | 25篇 |
金属工艺 | 7篇 |
机械仪表 | 15篇 |
建筑科学 | 9篇 |
能源动力 | 8篇 |
轻工业 | 237篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 23篇 |
一般工业技术 | 77篇 |
冶金工业 | 5篇 |
原子能技术 | 10篇 |
自动化技术 | 64篇 |
出版年
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 13篇 |
2017年 | 6篇 |
2016年 | 10篇 |
2015年 | 5篇 |
2014年 | 10篇 |
2013年 | 152篇 |
2012年 | 19篇 |
2011年 | 23篇 |
2010年 | 10篇 |
2009年 | 6篇 |
2008年 | 9篇 |
2007年 | 6篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 3篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 14篇 |
1997年 | 16篇 |
1996年 | 8篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1992年 | 2篇 |
1991年 | 11篇 |
1990年 | 4篇 |
1989年 | 11篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 3篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1972年 | 2篇 |
1971年 | 2篇 |
排序方式: 共有501条查询结果,搜索用时 0 毫秒
51.
52.
An analytical study is presented on the modal dispersion characteristics, group velocity, and effective group, as well as the phase index of a ternary one dimensional plasma photonic crystal for an obliquely incident electromagnetic wave considering the effect of collisions in plasma layers. The dispersion relation is derived by using the transfer matrix method and the boundary conditions based on electromagnetic theory. The dispersion curves are plotted for both the normal photonic band gap structure and the absorption photonic band gap structure. It is found that the increase in the angle of incidence shifts the photonic band gap toward higher frequencies. Also, the cutoff frequency is independent of collisions. 相似文献
53.
Outer layers of cotyledons of pigeonpea cultivar C 11 were successively scarified using a Tangential Abrasive Dehulling Device (TADD). Scarification for 0; 2, 4, 8, and 12 min resulted in the removal of 0, 6.7, 12.7, 25.3, and 36.9%, respectively, of powder fractions. The cotyledons and powder fractions at each level of scarification were analyzed for chemical composition, including minerals and trace elements, protein fractions, amino acid composition, and trypsin inhibitor acitivity (TIA). Protein, soluble sugars and ash of the dhal fraction (scarified cotyledons) decreased with increasing scarification time, while starch content increased. Considerable amounts of calcium (about 20%) and iron (about 30%) were removed by scarification for 4 min, but the process did not adversely affect protein quality in terms of amino acids. Trypsin inhibitors were not removed substantially by scarification. 相似文献
54.
Residence times of 1.0-2.0 cm potato cubes with 0.4-1.2% aqueous solutions of sodium carboxymethyl cellulose flowing at 453-599 mli sec were investigated in a vertical scraped surface heat exchanger rotating at 60 160 rpm. Minimum and maximum normalized particle residence times (NPRTs) standard deviation of mean NPRTs, and characteristic parameter for tanks-in-series models were not significantly affected by particle concentration. Mean NPRT for 40% particle concentration was significantly higher than those of single particle - 20% particle concentrations. Mean NPRTs were significantly influenced by process parameters and 2-way interactions. 相似文献
55.
RAJ N. SINGH 《Journal of the American Ceramic Society》1987,70(4):221-226
The roles of electrolyte composition and surface treatments in the phenomenon of asymmetric polarization in sodium β"-alumina ceramics are investigated. The results indicate that Asymmetric polarization is only displayed by electrolyte compositions containing 80 vol%β"-alumina phase and that a chemical treatment utilizing phosphoric acid, or a water treatment, is effective in circumventing the asymmetric polarization via removal of the asymmetric-polarization-causing resistive surface film. The surface film is soda rich, 20 to 40 nm thick, and there is a considerable concentration gradient from the surface into the bulk of an as-sintered sodium β"-alumina electrolyte. 相似文献
56.
A 30% concentrated permeate of a whey ultrafiltration process was used for producing crystalline a-lactose monohydrate. Effect of pH (2.75–5.5 pH units) at solvent to solute ratio 10:1 v/w, agitation and seeding (0.004–0.02%) on rate of lactose crystallization were examined. Conditions which were favorable in terms of crystallized lactose yield, and time of crystallization were: pH 5.5, agitation with or without seeding and 22°C. The first-order reaction-rate constant for crystallization ranged from 0.0178 to 0.200 hr?1 depending on conditions. 相似文献
57.
K.S. SEKHON NARPINDER SINGH H. KAUR H.P.S. NAGI 《Journal of Food Processing and Preservation》1995,19(2):147-160
The effect of reducing dough pH to 4.2 and addition of 2–4% gluten on rheological and pasting properties of sound and sprouted wheat flours are reported. Baking properties studied using "Medium Time Fermentation" and "Short Time Fermentation" methods revealed that an acceptable bread could be produced from even highly sprouted wheat by lowering the pH and adding 4% vital gluten to the flour, and using the "Short Time Fermentation Method". 相似文献
58.
ERIC SEBBEN DAVID C. SLAUGHTER R. PAUL SINGH 《Journal of Food Processing and Preservation》1998,22(4):265-282
The ultraviolet (UV), visible and near-infrared (NIR) absorption changes in corn oil were measured during processes simulating deep fat frying. Corn oil, maintained at 185C, was exposed to various treatments with nitrogen, air, water injection, air with water injection, and steam. Autoxidation due to a combination of air and high temperature in the simulated frying trials caused visible absorption changes between 400 and 580 nm as the oil deteriorated similar to those observed in potato frying experiments. These absorption changes were found to be associated with changes in an ultraviolet absorption band with a maximum near 270 nm. Second-derivative calibration equations developed at various visible and NIR absorption wavelengths successfully predicted the percentage of total polar materials (%TPM) which accumulated in the corn oil during simulated trials of autoxidation (R values from 0.93 to 0.98). Using spectral data from repetitive potato frying experiments, the predicted %TPM calculated with these equations correlated well with kinematic viscosity measurements (R values from 086 to 0.97). 相似文献
59.
60.