全文获取类型
收费全文 | 540篇 |
免费 | 25篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 7篇 |
综合类 | 1篇 |
化学工业 | 129篇 |
金属工艺 | 20篇 |
机械仪表 | 15篇 |
建筑科学 | 10篇 |
矿业工程 | 1篇 |
能源动力 | 14篇 |
轻工业 | 59篇 |
水利工程 | 3篇 |
石油天然气 | 3篇 |
无线电 | 68篇 |
一般工业技术 | 142篇 |
冶金工业 | 25篇 |
原子能技术 | 1篇 |
自动化技术 | 71篇 |
出版年
2023年 | 5篇 |
2022年 | 16篇 |
2021年 | 23篇 |
2020年 | 16篇 |
2019年 | 15篇 |
2018年 | 21篇 |
2017年 | 18篇 |
2016年 | 35篇 |
2015年 | 16篇 |
2014年 | 25篇 |
2013年 | 39篇 |
2012年 | 22篇 |
2011年 | 35篇 |
2010年 | 28篇 |
2009年 | 29篇 |
2008年 | 20篇 |
2007年 | 18篇 |
2006年 | 15篇 |
2005年 | 7篇 |
2004年 | 7篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 7篇 |
1996年 | 13篇 |
1995年 | 8篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 8篇 |
1980年 | 4篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有569条查询结果,搜索用时 15 毫秒
491.
Navin Chand Neelesh Rai S. L. Agrawal S. K. Patel 《Bulletin of Materials Science》2011,34(7):1297-1304
In the present work, an attempt has been made to develop nano aluminium oxide (Al2O3)-filled polyvinyl alcohol (PVA) composite gel electrolytes. Surface morphological studies, thermal behaviour, electrochemical stability and electrical characterization of these composite gel electrolytes have been performed. An increase in the concentration of Al2O3 in composite gel electrolytes increases the amorphous characteristics of pure PVA. Bulk conductivity of composite gel electrolytes increases by an order of magnitude on addition of a nano filler. Maximum conductivity of 5·81 × 10?2 S/cm is observed for 6 wt% Al2O3-filled polymer gel composite electrolytes. Temperature dependence of electrical conductivity shows a combination of Arrhenius and Vogel-Tamman-Fulcher (VTF) nature. Maximum current stability during oxidation and reduction cycle is noticed for 6 wt% Al2O3-filled PVA composite electrolyte, viz. ±1·65 V. 相似文献
492.
Umesh Chandra Lohani Jai Prakash Pandey Navin Chandra Shahi 《Food and Bioprocess Technology》2012,5(3):1113-1119
Polishing of barnyard millet was done in rice polisher. Degree of polishing was obtained from 3 to 6 min time of milling at
an increment of 1 min at 8%, 10%, 12% and 14% of moisture levels. At each moisture level and degree of polishing, proximate
compositions (protein, fat, fibre, ash and carbohydrates) were analysed. At 8% moisture, barnyard millet was more resistant
to polishing and yielded 18.86% of bran after 6 min of milling, while at 14% moisture it was 19.21%. The amount of bran removed
increased significantly with time of milling and was best described by power model when regression analysis was carried out.
The milling and head yield decreased linearly with the degree of polishing. For the entire range of milling time, at 10% moisture
content, there was highest head yield (52.97%). The broken millet recovery increased in proportion to the degree of polishing.
Regression analysis showed that the power model was the best fit. The milling time caused a reduction in the proximate compositions.
The maximum loss in protein, fat, ash and fibre took place at 14% moisture content followed by 12%, 10% and 8% moisture levels.
Protein, fat, ash and fibre were negatively and linearly correlated with degree of polishing. 相似文献
493.
Sukumar Debnath Navin K. Rastogi A.G. Gopala Krishna B.R. Lokesh 《Food and Bioproducts Processing》2012,90(2):249-256
The present work deals with the effect of frying cycles on physical, chemical and heat transfer quality of rice bran oil (RBO) during the preparation of poori (an Indian traditional fried food) by deep-fat frying. The frying was carried out in intermittent mode (5 batches each for 3 min in a day without any time lag) and repeated for 6 frying cycles. Result indicated that in first two cycles, free fatty acid content, peroxide value and total polar materials increased, while radical scavenging activity decreased. Further increase in frying cycles did not result in any significant changes in these parameters (p > 0.05). Similar trends were observed for these parameters in case of heating. Relative amounts of total saturated fatty acids increased due to marginal decrease in total unsaturated fatty acids content during frying cycles, however, no significant change was observed during heating. The convective heat transfer coefficient was found to decrease with an increase in frying cycle due to increase in kinematic viscosity of RBO for every frying or cycles. Despite the marginal changes in physical and chemical properties, there was no significant difference (p > 0.05) in the sensory characteristics of poori prepared in oil subjected to different cycles of frying. 相似文献
494.
P.K. BaviskarJ.B. Zhang V. GuptaS. Chand B.R. Sankapal 《Journal of Alloys and Compounds》2012,510(1):33-37
Cost effective, ruthenium metal free rhodamine B dye has been chemically adsorbed on ZnO films consisting of nanobeads to serve as a photo anode in dye sensitized solar cells. These ZnO films were chemically synthesized at room temperature (27 °C) on to fluorine doped tin oxide (FTO) coated glass substrates followed by annealing at 200 °C. These films consisting of inter connected nanobeads (20-40 nm) which are due to the agglomeration of very small size particles (3-5 nm) leading to high surface area. The film shows wurtzite structure having high crystallinity with optical direct band gap of 3.3 eV. Optical absorbance measurements for rhodamine B dye covered ZnO film revealed the good coverage in the visible region (460-590 nm) of the solar spectrum. With poly-iodide liquid as an electrolyte, device exhibits photon to electric energy conversion efficiency (η) of 1.26% under AM 1.5G illumination at 100 mW/cm2. 相似文献
495.
Poly(N-methylaniline) (PNMA), a electrically conductive derivative of polyaniline was synthesized by chemical polymerization of N-methylaniline (NmANI) using ammoniumpersulfate (APS) as an oxidizing agent and studied by electrical conductivity measurement, UV–vis and FTIR spectroscopy. The observed electrical conductivity was found to have a dependence on some synthesis parameters. The oxidant/monomer molar ratio ∼1 and p-toluenesulfonic acid (PTSA)/monomer molar ratio ∼4 showed higher values of electrical conductivity for the polymer. The d.c. conductivities of PTSA doped poly(N-methylaniline) have been measured in the temperature range 298–373 K. The conductivity of the samples has been observed to show an increasing trend with increasing temperature. However, on increasing temperature from 298 K to 373 K, the conductivity rise was found to be more for the samples having lower dopant/monomer ratio. The observed d.c. conductivity data was described by Mott's three-dimensional variable range hopping (VRH) model. 相似文献
496.
Satwinder S. Marwaha Rajesh Grover Chand Prakash John F. Kennedy 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1998,73(3):292-296
Three different support materials have been screened for immobilization of Phanerochaete chrysosporium for biobleaching of anaerobically digested black liquor. Of these, jute rope-immobilized P. chrysosporium showed better performance than cotton and wheat carriers in terms of decolorization and COD reduction. Process parameters such as temperature, mycelial load, pH, glucose concentration and retention time were optimized using jute-immobilized fungus and the optimal values recorded were 40°C, 340 mg, 5·5, 1% (w/v) and 72 h, respectively. Continuous biobleaching of anaerobically digested black liquor using a packed bed reactor system carrying the jute-immobilized fungal biomass was successfully carried out over a period of 21 days. © 1998 Society of Chemical Industry 相似文献
497.
Kevlar fibers (DuPont) and glass fibers have been used to reinforce linear lowdensity polyethylene (LLDPE) by using an elastic melt extruder and the compression molding technique. The impact behavior of hybrid composites of different compositions is compared and has been explained on the basis of volume fraction of fibers. The addition of glass fibers decreases the Izod impact strength of LLDPE. The Izod impact strength of the composite increses when glass fibers are replaced by Kevlar fibers. Dynamic mechanical α‐relaxation is studied and the effect of variation of fiber composition on the relaxation is reported in the temperature range from −50°C to 150°C at 1 Hz frequency. The α‐relaxation shifts towards the higher temperature side on addition of fibers in LLDPE. The addition of fibers increases the storage modulus, E′, of LLDPE. The hybridization of Kevlar and glass fibers helps in desiging composites with a desirable combination of impact strength and modulus. At the low temperature region, E′ increases significantly with glass fibers as compared to that noted with the addition of Kevlar fibers. The α‐transition temperature of composites increases significantly with Kevlar fibers as compared to that observed with addition of glass fibers. 相似文献
498.
Review Carbon fibers for composites 总被引:8,自引:0,他引:8
S. Chand 《Journal of Materials Science》2000,35(6):1303-1313
An attempt has been made to review and analyze the developments made during last few decades in the field of high performance carbon fibers. The focus is primarily on high technology sector, which includes aerospace and nuclear engineering or other areas, where the large scale use of carbon fibers is driven by maximum performance and not by cost factors. We have identified and suggested some specific areas for future research in order to minimize the gap between theoretical and practically realized tensile strengths and other mechanical properties of carbon fibers. 相似文献
499.
Ultrahigh molecular weight polyethylene (UHMWPE) modified polyester-cotton composites were developed and studied for friction and sliding wear behaviour at different applied loads and UHMWPE concentrations. Sliding wear tests were conducted by using pin-on-disc apparatus. Composites in the form of the pin were tested against EN-24 steel disc. The specific wear rate of polyester reduced on reinforcement of cotton and on addition of UHMWPE. The coefficient of friction of polyester resin increased on cotton reinforcement and reduced significantly on addition of UHMWPE in cotton polyester composite. The composites exhibited reductions in specific wear rate against the normal load in the specimens those containing 7.41 or higher volume percent of UHMWPE. The significant reduction in wear rate of UHMWPE modified polyester-cotton composite has been discussed with the help of SEM observations of worn surfaces and coefficient of friction. The addition of 14.19 vol.% UHMWPE in polyester resin brought down the value of μ to nearly half to that of polyester resin and 1/3rd of cotton polyester composite. 相似文献
500.