全文获取类型
收费全文 | 3655篇 |
免费 | 439篇 |
国内免费 | 210篇 |
专业分类
电工技术 | 33篇 |
综合类 | 333篇 |
化学工业 | 1371篇 |
金属工艺 | 105篇 |
机械仪表 | 92篇 |
建筑科学 | 236篇 |
矿业工程 | 108篇 |
能源动力 | 31篇 |
轻工业 | 1040篇 |
水利工程 | 67篇 |
石油天然气 | 335篇 |
武器工业 | 20篇 |
无线电 | 18篇 |
一般工业技术 | 458篇 |
冶金工业 | 50篇 |
原子能技术 | 1篇 |
自动化技术 | 6篇 |
出版年
2024年 | 31篇 |
2023年 | 71篇 |
2022年 | 138篇 |
2021年 | 167篇 |
2020年 | 134篇 |
2019年 | 135篇 |
2018年 | 131篇 |
2017年 | 190篇 |
2016年 | 153篇 |
2015年 | 152篇 |
2014年 | 159篇 |
2013年 | 181篇 |
2012年 | 252篇 |
2011年 | 240篇 |
2010年 | 169篇 |
2009年 | 152篇 |
2008年 | 175篇 |
2007年 | 219篇 |
2006年 | 201篇 |
2005年 | 192篇 |
2004年 | 185篇 |
2003年 | 142篇 |
2002年 | 126篇 |
2001年 | 127篇 |
2000年 | 89篇 |
1999年 | 72篇 |
1998年 | 68篇 |
1997年 | 48篇 |
1996年 | 48篇 |
1995年 | 27篇 |
1994年 | 30篇 |
1993年 | 20篇 |
1992年 | 22篇 |
1991年 | 22篇 |
1990年 | 10篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 4篇 |
1979年 | 1篇 |
排序方式: 共有4304条查询结果,搜索用时 265 毫秒
101.
Abstract: This study describes how the rheological properties of colloidal dispersions formed by heteroaggregation of oppositely charged protein‐coated lipid droplets depend on total particle concentration. Mixed‐particle emulsions were formed by mixing single‐particle emulsions containing either β‐lactoglobulin‐coated lipid droplets (ζ≈?42 mV, d43≈ 0.35 μm) or lactoferrin (LF)‐coated lipid droplets (ζ≈+26 mV, d43≈ 0.32 μm). A series of single‐particle and mixed‐particle emulsions with different total fat contents (5% to 40%) were prepared, and their mean particle size, apparent viscosity, and shear modulus were measured. Mixed‐particle emulsions (40% LF: 60%β‐Lg) containing relatively high fat contents (>10%) had high viscosities and paste‐like properties. These rheological characteristics were attributed to extensive particle aggregation and network formation due to electrostatic attraction between oppositely charged droplets. The viscosities of mixed‐particle emulsions were much higher than those of single‐particle emulsions with equivalent fat contents. Measurements of the color coordinates (L*, a*, b*) of mixed‐particle emulsions with low fat contents showed that they had similar appearances as single‐particle emulsions with high fat contents. This study has important implications for the creation of reduced fat foods with similar sensory qualities as higher fat foods. Practical Application: This study describes how novel food materials can be created by mixing together negatively charged and positively charged lipid droplets. These mixed emulsions may be suitable for the creation of reduced fat products, since they have high viscosities and paste‐like properties at relatively low fat contents. 相似文献
102.
Characteristics and Rheological Properties of Polysaccharide Nanoparticles from Edible Mushrooms (Flammulina velutipes)
下载免费PDF全文
![点击此处可从《Journal of food science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Wenhang Wang Cong Li Guanhua Du Xiuling Zhang Hongjie Zhang 《Journal of food science》2017,82(3):687-693
Nanotechnology has become relevant in the food‐related industries, and edible mushrooms can be a potential raw material for providing satisfied edible nanomaterial. In this study, by following 3 different pretreatments (hot water or cold alkali or hot alkali) insoluble polysaccharide nanoparticles were prepared from Flammulina velutipes by wet milling and high pressure homogenization and their properties were investigated. The resultant nanoparticles were characterized by SEM, GC‐MS (for its main compositions), FTIR, XRD, and TG. The 1 wt% nanoparticle dispersions presented non‐Newtonian, shear‐thinning fluids with the viscosity in an increasing order for the hot water < cold alkali < hot alkali. Moreover, the dynamical rheological results showed differences of storage (G′) and loss (G″) moduli of these particle dispersions. It was concluded that the Flammulina velutipes‐derived polysaccharides nanoparticles have great potential applications in the food industry, for example, as emulsifiers, reinforcement agents, and bioactive carriers. 相似文献
103.
Xuefeng Li Jingfang Zhang Xingping Zhou Chuan Lu Xiantao Tong Guoxing He Xiaqin Wang 《应用聚合物科学杂志》2012,126(1):110-115
Core‐shell fluoroacrylate copolymer latex was synthesized via semicontinuous seed emulsion polymerization, in which ethyl acrylate was utilized to prepare core, and methyl methacrylate, butyl acrylate, methacrylate acid, and hexafluorobutyl methacrylate were employed to constitute the shell. So the yielded latex particles had the soft core and hard shell. Multifunction and low viscosity of the latex had been applied as the binder of latex inks. The ζ potential showed that the latex particles had high thermodynamic stability. The latex and latex inks exhibited viscosity plateau of Newtonian fluid behaviors. Rheological tests revealed that viscous behaviors dominated in the latex and latex inks. However, there was some interaction among the latex and pigment particles. The hydrophobicity of the cast films of the latex increased with the amount of the fluoroacrylate monomer. Fluorine tended to migrate to the interface between the cast film and air. Therefore, the hydrophobicity was derived from the fluorine enrichment phenomena on the top side of the cast films. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
104.
Tatyana Aleksandrova Alexander Aleksandrov 《Mineral Processing and Extractive Metallurgy Review》2017,38(2):92-95
Experimental and theoretical studies of physical influence on the distribution of heavy metals and viscosity of heavy oils are given in the article. The oil of Yaregskoye (Timan-Pechora province) oil field was used as the test material. Microinclusions of metals (V, Ni, Ti, Fe, etc.) in the mineral parts were detected using scanning electron microscopy and electron microprobe analysis. In an attempt to extract these metals, effects of the extractant type, extractant concentration, and ultrasonic treatment on the extraction process were evaluated. 相似文献
105.
Yi Xiang Ruikun Wang Junhong Wu Junhu Zhou Kefa Cen 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2016,38(24):3687-3693
In this study, oilfield wastewater (OWW) was used to prepare coal–oilfield wastewater–slurry (COWS), and the apparent viscosity, solid concentration, and rheological curve were studied. Compared with original coal–water–slurry (CWS), the maximum solid concentration of COWS increased, and the viscosity decreased; therefore, the slurrying ability of the coal slurry was improved with the use of OWW. However, although the oil in OWW promoted the slurrying ability of the coal slurry, its effectiveness was insufficient, and a chemical additive was still needed to obtain a coal slurry with enhanced slurrying ability. Both COWS and CWS exhibited shear-thinning behavior, and the rheological index value of COWS was lower, which indicated that pseudoplasticity of COWS was more obvious, and OWW improved the rheological properties of coal slurry. 相似文献
106.
107.
108.
《中国有色金属学会会刊》2021,31(7):1868-1884
A new technique for preparing semisolid slurry, namely, distributary-confluence runner (DCR), was combined with die-casting (DC) to conduct rheological die-casting (R-DC) of A356 alloy. The mechanism of DCR for semisolid slurry preparation was determined via numerical simulations and experiments. The microstructure and mechanical properties of A356 alloys prepared via DC and R-DC were studied. High-quality slurry containing numerous primary α-Al (α1-Al) with an average size of 49 μm and a shape factor of 0.81 could be prepared via DCR. Simulation results indicated that the unique flow state and physical field changes during slurry preparation were conducive to accelerating the uniformity of melt temperature and composition fields, nucleation exfoliation, and spherical growth. Compared with the alloy prepared via DC, the tensile strength, yield strength, and elongation of A356 alloy prepared via R-DC increased by 19%, 15%, and 107%, respectively. 相似文献
109.
为了研究磁流变液在圆筒剪切模型中的流变特性,建立了以圆筒剪切模型为基础的实验装置。首先,通过理论分析得到了磁流变液在圆筒剪切模型中的层间传力模型,切应力和剪切速率测量方法。其次,通过ANSYS对圆筒剪切模型中磁流变液的磁场强度进行了仿真模拟,并以实验测量验证,得到了磁场强度分布。最后以理论分析为基础,通过实验测量得到了切应力与剪切速率和磁场强度之间的关系,并得到了拟合公式。实验表明,磁流变液流切应力与磁场强度的比值为0.162k Pa/m T,与剪切度率的比值为0.00026k Pa·s,磁场强度的增强能够较大地提升磁流变液的工作能力。 相似文献
110.
以羰基铁粉为磁性颗粒、甲基硅油和明胶/琼脂胶溶胶溶液的复合物为基体及各种添加剂制备了多组类液态磁流变复合胶样品。利用流变仪分别在旋转剪切模式和振荡剪切模式下对样品进行流变特性试验研究。结果表明,基体胶质物的含量对其流变特性影响较大。基体胶质物含量越高,剪切屈服强度越大且最大为92.1k Pa;胶质物含量对磁流变复合胶的线性粘弹性范围几乎没有影响;胶质物含量越高,磁流变复合胶的剪切储能模量越大,且绝对模量最大变化可达2.526MPa;添加纳米Si O2能提高磁流变复合胶的剪切屈服应力且能拓宽磁流变复合胶在磁场下的可调范围。 相似文献