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   317篇
  免费   28篇
  国内免费   1篇
电工技术   6篇
综合类   3篇
化学工业   84篇
金属工艺   3篇
机械仪表   20篇
建筑科学   7篇
能源动力   12篇
轻工业   61篇
水利工程   2篇
石油天然气   3篇
无线电   43篇
一般工业技术   57篇
冶金工业   14篇
自动化技术   31篇
  2024年   1篇
  2023年   3篇
  2022年   14篇
  2021年   19篇
  2020年   14篇
  2019年   13篇
  2018年   22篇
  2017年   11篇
  2016年   21篇
  2015年   9篇
  2014年   10篇
  2013年   36篇
  2012年   14篇
  2011年   22篇
  2010年   14篇
  2009年   13篇
  2008年   14篇
  2007年   13篇
  2006年   14篇
  2005年   8篇
  2004年   6篇
  2003年   6篇
  2002年   3篇
  2001年   2篇
  2000年   7篇
  1999年   3篇
  1998年   2篇
  1997年   4篇
  1996年   5篇
  1995年   1篇
  1994年   4篇
  1993年   1篇
  1992年   3篇
  1991年   1篇
  1990年   1篇
  1985年   2篇
  1984年   1篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   3篇
  1978年   1篇
  1975年   1篇
  1971年   1篇
排序方式: 共有346条查询结果,搜索用时 15 毫秒
251.
The generalised Reynolds' equation for Newtonian and non-Newtonian fluids, as applied to the wire-drawing process, together with the plasticity and energy equations have been adopted in solving the elasto-plastohydrodynamic lubrication problem in the wire-drawing process. The equations have been solved numerically using a finite difference technique with Gauss-Siedel iterative scheme to predict hydrodynamic behaviour and to correlate the forming parameters to the lubrication behaviour in an endeavour to find the optimum operating conditions for maximum precision and productivity. The effect of using either Newtonian or non-Newtonian lubricants on the process parameters has been also studied, to predict the most suitable lubricant type. The results indicate that the increase in the flow behaviour index increases the pressure gradient in the work zone, with a consequential reduction in oil film thickness. Also the minimum film thickness is highly influenced by the drawing speed. It can be concluded that the isothermal solution renders lower drawing stress than the adiabatic solution. The maximum shear stress, and hence the power loss, increases with the increase in die convergence angle.  相似文献   
252.
253.
The chemical composition of virgin olive oil may be influenced by genotype and different agronomic (i.e. fruit ripeness degree, water supply) and technological factors. This article reports the evaluation of the influence of the olive ripening stage on the quality indices, the major and the minor components and the oxidative stability of the two main monovarietal Tunisian cultivars (cvv. Chétoui and Chemlali) virgin olive oils. Moreover, the olives cv. Chétoui were tested in a rain-fed control and an irrigation regime. The oils sampled at five different ripeness stages were submitted to liquid chromatographic determination (HPLC-DAD/MSD) of their quali-quantitative phenolic and tocopherolic profiles. Moreover, the triacylglycerol and fatty acid compositions, and minor components such as squalene, pigments and their relation with the oil oxidative stability were evaluated. The tested oils showed very good correlation between the oxidative stability and the concentrations of total phenols, practically secoiridoids and α-tocopherol.  相似文献   
254.
An identification method of lard in chocolates using real-time polymerase chain reaction was developed to address Halal authentication. However, polymerase chain reaction detection of lard in chocolate has been in vain. In order to investigate the inhibitory effect exerted by each of the chocolate components, four basic chocolate components, sugar, milk powder, cocoa butter, and cocoa powder, were adulterated with lard and examined using porcine-specific real-time polymerase chain reaction assay. The results discovered cocoa powder, as the only component that prevents DNA extraction of lard in chocolate. No substantial polymerase chain reaction inhibition was detected, and thus confirms the cocoa powder’s inhibition on DNA extraction of lard from lard-adulterated chocolate. This finding will expedite new research to develop a method to dissociate the lard from the lard-cocoa powder complex, which will have high potential to be applied as a pre-treatment of the chocolate prior to the DNA extraction and polymerase chain reaction.  相似文献   
255.
The amphibious teleost Giant mudskipper (Periophthalmodon schlosseri, Pallas 1770) inhabit muddy plains and Asian mangrove forests. It spends more than 90% of its life outside of the water, using its skin, gills, and buccal-pharyngeal cavity mucosa to breathe in oxygen from the surrounding air. All vertebrates have been found to have mast cells (MCs), which are part of the innate immune system. These cells are mostly found in the mucous membranes of the organs that come in contact with the outside environment. According to their morphology, MCs have distinctive cytoplasmic granules that are released during the degranulation process. Additionally, these cells have antimicrobial peptides (AMPs) that fight a variety of infections. Piscidins, hepcidins, defensins, cathelicidins, and histonic peptides are examples of fish AMPs. Confocal microscopy was used in this study to assess Piscidin1 expression in Giant Mudskipper branchial MCs. Our results demonstrated the presence of MCs in the gills is highly positive for Piscidin1. Additionally, colocalized MCs labeled with TLR2/5-HT and Piscidin1/5-HT supported our data. The expression of Piscidin1 in giant mudskipper MCs highlights the involvement of this peptide in the orchestration of teleost immunity, advancing the knowledge of the defense system of this fish.  相似文献   
256.
Reproductive and metabolic anomalies in polycystic ovary syndrome (PCOS) have been associated with the dysregulation of sex steroid receptors. Kelulut honey (KH) has been shown to be beneficial in PCOS-induced rats by regulating folliculogenesis and the oestrus cycle. However, no study has been conducted to evaluate KH’s effect on sex steroid receptors in PCOS. Therefore, the current study examined the effects of KH, metformin, or clomiphene alone and in combination on the mRNA expression and protein distribution of androgen receptor (AR), oestrogen receptor α (ERα), oestrogen receptor β (ERβ), and progesterone receptor (PR) in PCOS-induced rats. The study used female Sprague-Dawley rats, which were treated orally with 1 mg/kg/day of letrozole for 21 days to develop PCOS. PCOS-induced rats were then divided and treated orally for 35 days with KH, metformin, clomiphene, KH + metformin, KH+ clomiphene and distilled water. In this study, we observed aberrant AR, ERα, ERβ and PR expression in PCOS-induced rats compared with the normal control rats. The effects of KH treatment were comparable with clomiphene and metformin in normalizing the expression of AR, ERα, and ERβ mRNA. However, KH, clomiphene and metformin did not affect PR mRNA expression and protein distribution. Hence, this study confirms the aberrant expression of sex steroid receptors in PCOS and demonstrates that KH treatment could normalise the sex steroid receptors profile. The findings provide a basis for future clinical trials to utilize KH as a regulator of sex steroid receptors in patients with PCOS.  相似文献   
257.
Wireless Personal Communications - Some channel coding schemes for 5G mobile communication system is facing difficulty in satisfying the user requirements in machine-type communication. This paper...  相似文献   
258.
Journal of Superconductivity and Novel Magnetism - CoNi films were elaborated by electrodeposition onto FTO substrates using a chloride bath with a metallic ion molar ratio [Co2+]/[Ni2+] equals...  相似文献   
259.
International Journal of Control, Automation and Systems - In this paper, a sliding mode control (SMC) using a novel dynamic sliding surface is proposed for multi-input multi-output (MIMO)...  相似文献   
260.
Telecommunication Systems - Orthogonal frequency division multiplexing based cooperative system using Alamouti space–time block coding at relay node represents an alternative solution to...  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