全文获取类型
收费全文 | 392篇 |
免费 | 22篇 |
专业分类
化学工业 | 115篇 |
金属工艺 | 1篇 |
机械仪表 | 7篇 |
建筑科学 | 30篇 |
能源动力 | 3篇 |
轻工业 | 111篇 |
水利工程 | 3篇 |
石油天然气 | 3篇 |
无线电 | 16篇 |
一般工业技术 | 45篇 |
冶金工业 | 43篇 |
原子能技术 | 1篇 |
自动化技术 | 36篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 17篇 |
2021年 | 20篇 |
2020年 | 10篇 |
2019年 | 8篇 |
2018年 | 11篇 |
2017年 | 15篇 |
2016年 | 16篇 |
2015年 | 9篇 |
2014年 | 13篇 |
2013年 | 29篇 |
2012年 | 32篇 |
2011年 | 28篇 |
2010年 | 23篇 |
2009年 | 29篇 |
2008年 | 25篇 |
2007年 | 20篇 |
2006年 | 26篇 |
2005年 | 15篇 |
2004年 | 13篇 |
2003年 | 11篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1984年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有414条查询结果,搜索用时 31 毫秒
11.
12.
13.
Improved pretreatments applied to the sugarcane bagasse and release of lignin and hemicellulose from the cellulose‐enriched fractions by sulfuric acid hydrolysis
下载免费PDF全文
![点击此处可从《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
14.
Dmytro Savytskii Marisa Sanders Roman Golovchak Brian Knorr Volkmar Dierolf Himanshu Jain 《Journal of the American Ceramic Society》2014,97(1):198-205
Congruent crystallization of antimony sulphoiodide (SbSI) glass of stoichiometric composition, which is prepared successfully for the first time using rapid melt‐quenching, has been investigated using differential scanning calorimetry (DSC). The results for glass powder show a glass transition at 127°C and two separate exothermal peaks with maxima around 140°C and 190°C. The ratio of the intensities of the exothermal peak at ~190°C to the peak at ~140°C increases as the particle size and heating rate are increased, but their total enthalpy remains constant at 62 ± 2 J/g for all DSC runs. Surface heating of the glass induced by a 520 nm CW laser shows two contracted regions: needle‐like crystalline formations at low temperature and bulk crystallization at high temperature. The observed phenomena and DSC results suggest two different kinds of crystallization of the SbSI phase: one‐dimensional crystallization at low temperature which starts from the sample surface and three‐dimensional bulk crystallization that continues the transformation to crystalline state at higher temperatures. The origin of the two different crystallizations can be traced to the strong anisotropy of the SbSI crystal structure due to the weak van der Waals interaction between covalent‐ionic chains (Sb2S2I2)n. 相似文献
15.
16.
Catanozi S Rocha JC Passarelli M Mesquita CH Suguiama VY Guzzo ML dos Santos Filho A Quintão EC Nakandakare ER 《Lipids》2006,41(7):663-668
Dyslipoproteinemia of the Nagase analbuminemic rat (NAR) is characterized by elevated concentrations of VLDL and LDL attributed
to increased rates of liver lipoprotein synthesis. Increased lysophosphatidylcholine (LPC) in NAR HDL has been attributed
to high plasma LCAT activity. We show here that, as compared with Sprague-Dawley rats (SDR), NAR plasma triacylglycerol (TAG),
total cholesterol (TC), HDL TAG, protein, total phospholipids (PL), LPC, and PS are increased. These alterations rendered
the NAR HDL particle more susceptible to the activity of the enzyme hepatic lipoprotein lipase (HL), which otherwise was unaltered
in our study. Fractional catabolic rates in blood of the autologous 125I-apoHDL (median and lower quartile values), were, respectively, 0.231 and 1.645 (n=10) in NAR as compared with 0.140 and 0.109 (n=10) in SDR (P=0.012), corresponding to synthesis rates of HDL protein of 89.8±33.7 mg/d in NAR and 17.4±6.5 mg/d in SDR (P=0.0122). Furthermore, Swiss mouse macrophage free-cholesterol (FC) efflux rates, measured as the percent [14C]-cholesterol efflux/6 h, were 8.2±2.3 (n=9) in NAR HDL and 11.2±3.2 (n=10) in SDR HDL (P=0.03). Therefore, in NAR the modification of the HDL composition slows down the cell FC efflux rate, and together with the
increased rate of plasma HDL metabolism influences the reverse cholesterol transport system. 相似文献
17.
Renan C. Chisté Marisa Freitas Adriana Z. Mercadante Eduarda Fernandes 《Journal of food science》2014,79(9):H1841-H1847
β‐Carotene, zeaxanthin, lutein, β‐cryptoxanthin, and lycopene are liposoluble pigments widely distributed in vegetables and fruits and, after ingestion, these compounds are usually detected in human blood plasma. In this study, we evaluated their potential to inhibit hemolysis of human erythrocytes, as mediated by the toxicity of peroxyl radicals (ROO?). Thus, 2,2′‐azobis (2‐methylpropionamidine) dihydrochloride (AAPH) was used as ROO? generator and the hemolysis assay was carried out in experimental conditions optimized by response surface methodology, and successfully adapted to microplate assay. The optimized conditions were verified at 30 × 106 cells/mL, 17 mM of AAPH for 3 h, at which 48 ± 5% of hemolysis was achieved in freshly isolated erythrocytes. Among the tested carotenoids, lycopene (IC50 = 0.24 ± 0.05 μM) was the most efficient to prevent the hemolysis, followed by β‐carotene (0.32 ± 0.02 μM), lutein (0.38 ± 0.02 μM), and zeaxanthin (0.43 ± 0.02 μM). These carotenoids were at least 5 times more effective than quercetin, trolox, and ascorbic acid (positive controls). β‐Cryptoxanthin did not present any erythroprotective effect, but rather induced a hemolytic effect at the highest tested concentration (3 μM). These results suggest that selected carotenoids may have potential to act as important erythroprotective agents by preventing ROO?‐induced toxicity in human erythrocytes. 相似文献
18.
Marisa Falco Jaime Retuert Alexis Hidrobo Cristian Covarrubias Paulo Araya Ulises Sedran 《Applied Catalysis A: General》2009,366(2):269-274
Mesoporous amorphous silica-aluminas were synthesised with standard aluminium and silicon sources by means of the formation of inorganic–organic composites with the addition of chitosan biopolymer, and compared to analogous catalysts synthesised conventionally. Some catalysts were subjected to hydrothermal treatment. The resulting specific surface areas were from 480 to 573 m2/g in the untreated samples and 300–430 m2/g in the hydrotreated catalysts, average pore sizes ranging from 32 to 100 Å with sharp, unimodal distributions. The chitosan materials showed higher specific surface areas and larger pore sizes than those of their non-chitosan counterparts. The most important differences in the acidic properties were in the relationships between tetrahedral and octahedral aluminium atoms, the chitosan materials having higher relative amounts of tetrahedral aluminium than the conventional silica-aluminas. Evidences of stabilization in the physical and chemical properties were observed in the chitosan-containing catalysts. The catalytic performance was evaluated with the conversion of tri-isopropylbenzene at 400 °C, to assess activity and accessibility, and cyclohexene at 300 °C, to assess hydrogen transfer properties. The highest activity and accessibility was observed in the hydrotreated, chitosan-containing catalyst, while hydrogen transfer capabilities were similar to those of medium unit cell sizes, equilibrium commercial FCC catalysts. 相似文献
19.
Marisa Di Sabatino Mari Juel Lars Arnberg Martin Syvertsen Gabriella Tranell 《Transactions of the Indian Institute of Metals》2009,62(4-5):511-513
Two different cooling rates have been imposed during the early solidification of two multi-crystalline silicon ingots with 250mm diameter and 100mm height in a pilot scale directional solidification furnace. This has been done by opening a variable heat leak system below the crucible in order to achieve a high initial cooling rate in one of the ingots. The grain-structure and -orientation of these two ingots have been investigated by light microscopy (LM) and electron backscattered diffraction (EBSD), and their electrical properties by quasi-steady state photo-conductance (QSSPC) and surface photovoltage (SPV) method. The ingot with the high initial cooling rate shows predominantly grains which are significantly larger than what is usually found in mc-Si. The minority carrier diffusion lengths measured on the large grains in the ingot with high cooling rate show higher values than those measured on the ingot with smaller grains. These results indicate that principles of grain size and -orientation control in mc-Si ingots can be applied to a pilot scale furnace, and the potential for up-scaling to industrial ingots with improved electrical properties and, thus, higher solar cell conversion efficiency. 相似文献
20.
Beeble Marisa L.; Bybee Deborah; Sullivan Cris M.; Adams Adrienne E. 《Canadian Metallurgical Quarterly》2009,77(4):718
Intimate partner violence is a serious and pervasive social problem with deleterious consequences for survivors’ well-being. The current study involved interviewing 160 survivors 6 times over 2 years to examine the role of social support in explaining or buffering these negative psychological consequences. The authors examined both between- and within-persons variability to explore women’s trajectories regarding their experiences of abuse, social support, depression, and quality of life (QOL). Findings revealed the complex role of social support on women’s well-being. Evidence was found for main, mediating, and moderating effects of social support on women’s well-being. First, social support was positively related to QOL and negatively related to depression. Social support also partially explained the effect of baseline level and subsequent change in physical abuse on QOL and depression over time, partially mediated the effects of change in psychological abuse, and moderated the impact of abuse on QOL. The buffering effects of social support were strongest at lower levels of abuse. Implications for future research and intervention are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献