全文获取类型
收费全文 | 2307篇 |
免费 | 241篇 |
国内免费 | 22篇 |
专业分类
电工技术 | 19篇 |
综合类 | 116篇 |
化学工业 | 491篇 |
金属工艺 | 8篇 |
机械仪表 | 87篇 |
建筑科学 | 31篇 |
矿业工程 | 7篇 |
能源动力 | 62篇 |
轻工业 | 1537篇 |
水利工程 | 11篇 |
石油天然气 | 57篇 |
无线电 | 12篇 |
一般工业技术 | 90篇 |
冶金工业 | 13篇 |
自动化技术 | 29篇 |
出版年
2024年 | 17篇 |
2023年 | 61篇 |
2022年 | 80篇 |
2021年 | 98篇 |
2020年 | 106篇 |
2019年 | 85篇 |
2018年 | 87篇 |
2017年 | 96篇 |
2016年 | 70篇 |
2015年 | 85篇 |
2014年 | 109篇 |
2013年 | 113篇 |
2012年 | 142篇 |
2011年 | 133篇 |
2010年 | 80篇 |
2009年 | 82篇 |
2008年 | 68篇 |
2007年 | 130篇 |
2006年 | 137篇 |
2005年 | 122篇 |
2004年 | 94篇 |
2003年 | 91篇 |
2002年 | 70篇 |
2001年 | 61篇 |
2000年 | 68篇 |
1999年 | 44篇 |
1998年 | 43篇 |
1997年 | 33篇 |
1996年 | 29篇 |
1995年 | 25篇 |
1994年 | 27篇 |
1993年 | 21篇 |
1992年 | 19篇 |
1991年 | 13篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 9篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有2570条查询结果,搜索用时 218 毫秒
131.
植物油是一类经植物原料提取的富含多种微量营养成分的油脂。角鲨烯是植物油中营养伴随物之一,对人体生理健康?和疾病预防有着积极作用。通常,不同种类植物油中角鲨烯含量差距明显,甚至同种植物油中角鲨烯含量因地域、提取部位、加工工艺等因素而存在显著差异。因此,了解植物油角鲨烯含量并探究影响其角鲨烯含量的因素,可有效保存其角鲨烯成分,提升植物油营养品质和健康价值。本文介绍了多种植物油角鲨烯含量,并分析比较了植物油种类,原料品种、成熟度、产地、提取部位及油脂提取工艺、精炼工艺、储藏条件对其角鲨烯含量的影响,以期为优化植物油选择及改进加工工艺提供参考,并且为进一步提升植物油营养品质和健康价值提供理论基础。 相似文献
132.
儿童适宜型天然复合蔬菜澄清汁的研制 总被引:1,自引:0,他引:1
从天然蔬菜中精选出蕃茄、胡萝卜、蘑菇、苦瓜、芹菜、菠菜制取蔬菜单汁,根据一定的复制原则和复配工艺进行复配,并对复配后的复合蔬菜汁进行了澄清实验,最终得到一种儿童适宜型复合蔬菜汁。 相似文献
133.
134.
ABSTRACT: The development of a structural fat network in ice cream as influenced by the solid:liquid fat ratio at the time of freezing/whipping was investigated. The solid fat content was varied with blends of a hard fraction of palm kernel oil (PKO) and high-oleic sunflower oil ranging from 40% to 100% PKO. Fat globule size and adsorbed protein levels in mix and overrun, fat destabilization, meltdown resistance, and air bubble size in ice cream were measured. It was found that blends comprising 60% to 80% solid fat produced the highest rates of fat destabilization that could be described as partial coalescence (as opposed to coalescence), lowest rates of meltdown, and smallest air bubble sizes. Lower levels of solid fat produced fat destabilization that was better characterized as coalescence, leading to loss of structural integrity, whereas higher levels of solid fat led to lower levels of fat network formation and thus also to reduced structural integrity. Practical Application: Blends of highly saturated palm kernel oil and monounsaturated high-oleic sunflower oil were used to modify the solid:liquid ratio of fat blends used for ice cream manufacture. Blends that contained 60% to 80% solid fat at freezing/whipping temperatures produced optimal structures leading to low rates of meltdown. This provides a useful reference for manufacturers to help in the selection of appropriate fat blends for nondairy-fat ice cream. 相似文献
135.
M. Acaroglu A. Demirbas 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2013,35(8):705-712
Abstract The viscosity values of vegetable oils vary between 27.2 and 53.6 mm2/s, whereas those of vegetable oil methyl esters between 3.59 and 4.63 mm2/s. The viscosity values of vegetable oil methyl esters highly decreases after transesterification process. Compared to no. 2 diesel fuel, all of the vegetable oil methyl esters were slightly viscous. The flash point values of vegetable oil methyl esters are highly lower than those of vegetable oils. The flash point values of vegetable oil methyl esters are highly lower than those of vegetable oils. An increase in density from 860 to 885 kg/m3 for vegetable oil methyl esters or biodiesels increases the viscosity from 3.59 to 4.63 mm2/s, and the increases are highly regular. There is high regression between density and viscosity values vegetable oil methyl esters. The relationships between viscosity and flash point for vegetable oil methyl esters are irregular. An increase in density from 860 to 885 kg/m3 for vegetable oil methyl esters increases the flash point from 401 to 453 K, and the increases are slightly regular. 相似文献
136.
Nasirullah Rizwan Shariff Umesha Shankara Shetty Reddy Sunki Yella 《International Journal of Food Science & Technology》2010,45(7):1395-1402
Edible vegetable oil blends, such as coconut:linseed; coconut:safflower; coconut:sunflower; coconut:rice‐bran oils; in the ratio of 70:30 and 60:40 v/v and pure coconut oil (CNO) were interesterified using sodium methoxide 0.5% and subsequently refined to prepare nutritionally superior flowable CNO blends which remained liquid even at sub‐zero temperatures. The slip melting point of chemically interesterified fats could not be determined as they are liquified just after removing from freezing chamber in comparison with the slip melting point of 21.5–26.5 °C for their uninteresterified counterparts. These interesterified fats were liquid and flowable at 6 °C for more than 4 h in a cooling chamber and their solidification temperature ranged between ?2.0 and ?5.5 °C. Free fatty acids showed an increasing trend from 0.35% to 2.0% resulting in decrease in triglycerides After refining these oil blends showed values similar to their controls. However, iodine value of interesterified and uninteresterified oils were close to each other. Differential scanning calorimetry showed the onset of crystallisation at lower temperatures and lower solid fat content for interesterified fats. A nutritionally superior combination of CNO blend which is flowable at low temperature could be prepared. 相似文献
137.
Choo Wee Sim Kharidah Muhammad Salmah Yusof Jamilah Bakar & Dzulkifly Mat Hashim 《International Journal of Food Science & Technology》2004,39(9):947-958
Response Surface Methodology (RSM) was used to establish the optimum time and temperature for production of acid‐hydrolysed winged bean protein (aHWBP) and acid‐hydrolysed soybean protein (aHSBP). Seven hours of hydrolysis at 125 °C was the optimum condition for producing aHWBP, whereas it was 5 h of hydrolysis at 125 °C for production of aHSBP. Although aHWBP and aHSBP produced using these conditions had favourable sensory qualities, they were found to have up to 25 mg kg?1 of 3‐monochloropropane‐1,2‐diol (3‐MCPD). This exceeds the maximum level permissible in Commission Regulation (EC) No 466/2001. However, additional alkaline thermal treatment at pH 8.5 for 2 h at 100 °C effectively reduced the 3‐MCPD contents of aHWBP and aHSBP to undetectable levels. aHWBP has a distinctive flavour, which is different from that of aHSBP. The former has higher mean scores for meaty and vegetable attributes but lower mean scores for soy, umami and beany attributes than the latter. 相似文献
138.
139.
140.
Application of principal-component analysis on near-infrared spectroscopic data of vegetable oils for their classification 总被引:3,自引:0,他引:3
Tetsuo Sato 《Journal of the American Oil Chemists' Society》1994,71(3):293-298
In the near-infrared (NIR) spectra of oil, information about fatty acid composition is concentrated in the range of 1600–2200
nm. Principal-component analysis (PCA) was applied on the standardized full NIR spectral data of this region for vegetable
oils to totally capture the NIR spectral pattern. Nine varieties of vegetable oils (soybean, corn, cottonseed, olive, rice
bran, peanut, rapeseed, sesame and coconut oil) could be successfully classified from their PCA scores. Examining the contribution
of wavelengths to PCA scores showed that wavelengths with a high loading weight were assigned to characteristic absorption
regions that correspond to specific fatty acid moieties. This classification is related to the fatty acid composition of an
oil, and it can be carried out rapidly and easily after eigenvectors were obtained. 相似文献