首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   532961篇
  免费   9356篇
  国内免费   3941篇
电工技术   11458篇
技术理论   8篇
综合类   3701篇
化学工业   79821篇
金属工艺   25652篇
机械仪表   20397篇
建筑科学   14993篇
矿业工程   4582篇
能源动力   12879篇
轻工业   39503篇
水利工程   6118篇
石油天然气   13308篇
武器工业   486篇
无线电   60314篇
一般工业技术   104812篇
冶金工业   85365篇
原子能技术   11959篇
自动化技术   50902篇
  2022年   3479篇
  2021年   5233篇
  2020年   3947篇
  2019年   4405篇
  2018年   13863篇
  2017年   14533篇
  2016年   11049篇
  2015年   6142篇
  2014年   8955篇
  2013年   21433篇
  2012年   15753篇
  2011年   25147篇
  2010年   21195篇
  2009年   21870篇
  2008年   22072篇
  2007年   23443篇
  2006年   14459篇
  2005年   16302篇
  2004年   13933篇
  2003年   13027篇
  2002年   11849篇
  2001年   11289篇
  2000年   10925篇
  1999年   11426篇
  1998年   25612篇
  1997年   18404篇
  1996年   14338篇
  1995年   11095篇
  1994年   9620篇
  1993年   9449篇
  1992年   6896篇
  1991年   6577篇
  1990年   6292篇
  1989年   6236篇
  1988年   5880篇
  1987年   5231篇
  1986年   5172篇
  1985年   5773篇
  1984年   5308篇
  1983年   4935篇
  1982年   4596篇
  1981年   4690篇
  1980年   4574篇
  1979年   4359篇
  1978年   4350篇
  1977年   4903篇
  1976年   6431篇
  1975年   3716篇
  1974年   3669篇
  1973年   3747篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
61.
62.
This study evaluated several physical and sensory parameters of different types of cheese available in the Polish market. The measurements of textural properties were conducted in an Instron universal testing machine, while the colour properties of cheeses were measured using a Minolta chromameter. The chemical composition was determined by means of the near‐infrared spectroscopy (NIRs). Moreover, a trained sensory panel was invited to assess the cheese texture‐related properties. Generally, cheeses with reduced fat content were characterised by higher hardness, adhesiveness, cohesiveness and elasticity. Texture‐related parameters of cheese with canola oil were comparable to that of most of full‐fat cheeses. The correlation analysis between physical and sensory attributes related to cheese textural properties indicated the potential applications of TPA, shear and penetration tests (= 0.766, = 0.75 and = 0.765, respectively) for the evaluation of sensory properties related to the hardness. Meanwhile, the elasticity of cheese obtained from sensory evaluation was strongly correlated with the elasticity determined from the shear test (= 0.722) and moderately correlated with the elasticity from penetration test (= 0.588), indicating a need to refine the method of penetration test. In addition, cheeses exhibited higher meltability during convection heating at 230 °C than microwave heating. The values of meltability for cheese with reduced fat content were lower than those of full‐fat cheese.  相似文献   
63.
64.
65.
66.
67.
68.
69.
Many e-commerce companies collect users’ personal data for marketing purposes despite privacy concerns. Information-collecting companies often offer a monetary reward to users to alleviate privacy concerns and ease the collection of personal information. This study focused on the negative effects of monetary rewards on both information privacy concerns (IPC) and information disclosure. A survey approach was used to collect data and 370 final responses were analysed using a two-way analysis of variance and a binomial logistic regression model. The results show that monetary rewards increase IPC when an information-collecting company requires sensitive information. Additional results indicate that building trust is a more effective way of collecting personal data. This study identifies how organisations can best execute information-collection activities and contributes additional insights for academia and practitioners.  相似文献   
70.
Enhancement of the dissolution rate of the poorly water-soluble hypoglycemic agent, gliclazide, by the aid of lyophilization was investigated. Mannitol, sodium lauryl sulfate (SLS) and polyvinyl pyrrolidone (PVP-k-30) were employed in different weight ratios (43%, 56% and 64% w/w, respectively) as water-soluble excipients in the formulation. Lyophilized systems were found to exhibit extremely higher in vitro dissolution rate compared to the unprocessed drug powder. Solid state characterization of the lyophilized systems using X-ray powder diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry techniques revealed that dissolution enhancement was attributable to transformation of gliclazide from the crystalline to an amorphous state in the solid dispersion formed during the lyophilization process. The gastrointestinal absorption and hypoglycemic effect of the lyophilized gliclazide/SLS system were investigated following oral administration to Albino rabbits. Cmax and area under the plasma concentration–time curve of gliclazide (AUC0–12) after administration of the lyophilized formulations were significantly higher than those obtained after administration of the unprocessed gliclazide.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号