全文获取类型
收费全文 | 640篇 |
免费 | 63篇 |
专业分类
电工技术 | 9篇 |
化学工业 | 197篇 |
金属工艺 | 6篇 |
机械仪表 | 3篇 |
建筑科学 | 17篇 |
矿业工程 | 1篇 |
能源动力 | 16篇 |
轻工业 | 208篇 |
水利工程 | 7篇 |
石油天然气 | 1篇 |
无线电 | 14篇 |
一般工业技术 | 55篇 |
冶金工业 | 102篇 |
原子能技术 | 1篇 |
自动化技术 | 66篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 16篇 |
2021年 | 40篇 |
2020年 | 20篇 |
2019年 | 20篇 |
2018年 | 20篇 |
2017年 | 29篇 |
2016年 | 20篇 |
2015年 | 27篇 |
2014年 | 32篇 |
2013年 | 43篇 |
2012年 | 44篇 |
2011年 | 36篇 |
2010年 | 36篇 |
2009年 | 27篇 |
2008年 | 23篇 |
2007年 | 28篇 |
2006年 | 31篇 |
2005年 | 25篇 |
2004年 | 8篇 |
2003年 | 10篇 |
2002年 | 11篇 |
2001年 | 3篇 |
2000年 | 12篇 |
1999年 | 4篇 |
1998年 | 38篇 |
1997年 | 22篇 |
1996年 | 17篇 |
1995年 | 15篇 |
1994年 | 12篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
排序方式: 共有703条查询结果,搜索用时 15 毫秒
111.
Development of engineered cementitious composites with limestone powder and blast furnace slag 总被引:1,自引:1,他引:0
Jian Zhou Shunzhi Qian M. Guadalupe Sierra Beltran Guang Ye Klaas van Breugel Victor C. Li 《Materials and Structures》2010,43(6):803-814
Nowadays limestone powder and blast furnace slag (BFS) are widely used in concrete as blended materials in cement. The replacement
of Portland cement by limestone powder and BFS can lower the cost and enhance the greenness of concrete, since the production
of these two materials needs less energy and causes less CO2 emission than Portland cement. Moreover, the use of limestone powder and BFS improves the properties of fresh and hardened
concrete, such as workability and durability. Engineered cementitious composites (ECC) is a class of ultra ductile fiber reinforced
cementitious composites, characterized by high ductility, tight crack width control and relatively low fiber content. The
limestone powder and BFS are used to produce ECC in this research. The mix proportion is designed experimentally by adjusting
the amount of limestone powder and BFS, accompanied by four-point bending test and uniaxial tensile test. This study results
in an ECC mix proportion with the Portland cement content as low as 15% of powder by weight. This mixture, at 28 days, exhibits
a high tensile strain capacity of 3.3%, a tight crack width of 57 μm and a moderate compressive strength of 38 MPa. In order
to promote a wide use of ECC, it was tried to simplify the mixing of ECC with only two matrix materials, i.e. BFS cement and
limestone powder, instead of three matrix materials. By replacing Portland cement and BFS in the aforementioned ECC mixture
with BFS cement, the ECC with BFS cement and limestone powder exhibits a tensile strain capacity of 3.1%, a crack width of
76 μm and a compressive strength of 40 MPa after 28 days of curing. 相似文献
112.
113.
114.
Physicochemical Changes of Connective Tissue Proteins in Jumbo Squid (Dosidicus gigas) Muscle During Ice Storage 下载免费PDF全文
115.
Effects of novel nitrite packaging film on the bacterial growth of bison strip‐loin steaks 下载免费PDF全文
116.
Combined Effect of Ultrasound and Mild Temperatures on the Inactivation of E. coli in Fresh Carrot Juice and Changes on its Physicochemical Characteristics 下载免费PDF全文
117.
J.L. Gautier J.P. Monrás I.O. Osorio-Román C.C. Vásquez D. Bravo T. Herranz J.F. Marco J.M. Pérez-Donoso 《Materials Chemistry and Physics》2013
The surface characterization of CdTe QDs synthesized by a novel procedure using glutathione (GSH), low temperatures (60–90 °C) and K2TeO3 as the –Te precursor is reported. Fluorescence of the produced QDs is stable in the pH range 6–13 and QDs inside eukaryotic cells are highly fluorescent. The surface composition of GSH-CdTe QDs with different spectroscopic properties and particle size distributions was determined by XPS. The XPS analysis indicated that the QDs are essentially CdTe, although all nanoparticles contain 12–24% of CdO (and in one case also TeO2). GSH decomposes with reaction time releasing small amounts of S−2 ions that react with Cd(Te) to yield Cd(Te)S in a smaller amount than that of CdTe. Finally, the use of QDs in fluorescence mediated immunodetection of bacterial pathogens has been evaluated. 相似文献
118.
Kharla A. Segovia‐Bravo Pedro García‐García Antonio López‐López Antonio Garrido‐Fernández 《Journal of food science》2012,77(5):S194-S201
Abstract: Subjecting bruised olives to a nitrogen atmosphere during the postharvest period prevented the oxidation of phenols and subsequent browning. However, a rapid phenol oxidation and browning occurred when fruits were re‐exposed to air. Based on models deduced from the effects of aqueous antioxidant solutions on changes in different color parameters in the fermented product, the treatments to prevent browning were optimized. The recommended procedure consists of placing the harvested olives in a cold (4 to 8 °C) solution of 3% sodium metabisulfite with the pH adjusted to 3.0 (by adding food grade HCl) and applying the lye treatment before 8 h from picking. The use of these conditions led to mechanically harvested Spanish style olives with hardly any visible browning. Practical Application: The procedure developed may be applicable to prevent browning on the bruised areas of manually or mechanically harvested olives. The system is simple, requires low investment, and may lead, in fermented olives, to undetectable differences between undamaged and bruised areas and better ratings in the visual observation of healthy fruits. 相似文献
119.
Diago MP Ayestarán B Guadalupe Z Garrido Á Tardaguila J 《Journal of the science of food and agriculture》2012,92(4):925-934
BACKGROUND: Early defoliation is a viticultural practice aimed at crop control. So far, the impact of early leaf removal on the monomeric phenolic composition of wines has not been explored. This study examines the effects of early defoliation on the phenolic profile and content in Tempranillo wines. The influence of the defoliation method (manual vs mechanical) and the timing of leaf removal (pre‐bloom vs fruit set) was investigated. RESULTS: Over two consecutive seasons, 2007 and 2008, the monomeric phenolic composition in Tempranillo wines was studied by high‐performance liquid chromatography with photodiode array detection, and 22 compounds were identified and quantified. Overall, early defoliation led to wines more intensely coloured, of higher alcohol content and with larger concentrations of hydroxycinnamic acids, flavonols and anthocyanins (in 2008 only for mechanical treatments). In the absence of fungal infection, resveratrol was found to increase in wines corresponding to early defoliation treatments. The method of leaf removal seemed to be more critical than the timing of intervention, and larger effects on wine phenolic composition were observed for mechanical treatments. CONCLUSION: Early defoliation proved to be an effective technique for improving the phenolic composition of Tempranillo wines, by favouring the accumulation of hydroxycinnamics, flavonols and anthocyanins. This is an important achievement, as wine quality is often described by its colour and phenolic attributes. Copyright © 2011 Society of Chemical Industry 相似文献
120.
Jesus Guardiola Jose M. Aragón Guadalupe Ramos Rosario Elvira Daniel Martín 《American Institute of Chemical Engineers》2012,58(12):3645-3652
The fine tuning of a sensor designed to locate interfaces using a two‐dimensional gas–solid fluidized bed (FB) as reference is described. The sensor works through computer vision and consists of a charge coupled device camera that is placed alongside the bed and, as the human eye would do, first establishes a straight segment of the bed's top surface to define the phase boundary and then through pattern recognition continuously scans the interface in search of a similar pattern. The field of view is 582 × 752 pixels2. The experimentally measured Pixel size is 216 × 208 μm2. The device allows for experimentally obtaining the position of the probe with a resolution of ± 0.01 pixels at 25 Hz. We also describe its use to measure the height of the FB and observe a linear relationship with fluidization velocity. © 2012 American Institute of Chemical Engineers AIChE J, 2012 相似文献