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   203篇
  免费   11篇
  国内免费   5篇
电工技术   3篇
综合类   1篇
化学工业   53篇
金属工艺   10篇
机械仪表   4篇
建筑科学   6篇
能源动力   10篇
轻工业   26篇
水利工程   4篇
石油天然气   16篇
无线电   16篇
一般工业技术   32篇
冶金工业   7篇
原子能技术   3篇
自动化技术   28篇
  2023年   2篇
  2022年   9篇
  2021年   15篇
  2020年   6篇
  2019年   18篇
  2018年   17篇
  2017年   10篇
  2016年   9篇
  2015年   11篇
  2014年   16篇
  2013年   19篇
  2012年   10篇
  2011年   18篇
  2010年   8篇
  2009年   9篇
  2008年   5篇
  2007年   9篇
  2006年   3篇
  2005年   2篇
  2004年   3篇
  2001年   2篇
  2000年   4篇
  1999年   2篇
  1998年   2篇
  1997年   1篇
  1989年   1篇
  1987年   1篇
  1984年   1篇
  1983年   1篇
  1980年   2篇
  1979年   1篇
  1977年   1篇
  1976年   1篇
排序方式: 共有219条查询结果,搜索用时 310 毫秒
21.
22.
23.
24.
25.
Opopanax gum/gelatin nanofibre was produced by the electrospinning method, and the efficiency of this new technique for encapsulation of garlic essential oil was investigated. Fourier-transform infrared spectroscopy results showed the physical and weak interactions between opopanax gum and gelatin, as well as the improvement of their thermal stability in the nanofibres structure. Incorporating 10% garlic essential oil based on biopolymer weight in nanofibres was considered the best percentage. The results confirmed the presence of garlic essential oil in the nanofibres and the improvement of its thermal stability by entrapment to the nanofibre structure. The data of analysis of the stability of garlic essential oil in the forms of free and encapsulated conditions showed that its stability increased at 25 °C from 20 days to more than 60 days. It indicated the efficiency of opopanax gum/gelatin nanofibres as an applicable coating material for stability enhancement of essential oils.  相似文献   
26.
27.
Water Resources Management - Sustainable utilization of water resources requires preventive measures that must be taken to promote optimal use of water resources together with consideration of...  相似文献   
28.
Advanced forms of hydrogels have many inherently desirable properties and can be designed with different structures and functions. In particular, bioresponsive multifunctional hydrogels can carry out sophisticated biological functions. These include in situ single-cell approaches, capturing, analysis, and release of living cells, biomimetics of cell, tissue, and tumor-specific niches. They can allow in vivo cell manipulation and act as novel drug delivery systems, allowing diagnostic, therapeutic, vaccination, and immunotherapy methods. In the present review of multitasking hydrogels, new approaches and devices classified into point-of-care testing (POCT), microarrays, single-cell/rare cell approaches, artificial membranes, biomimetic modeling systems, nanodoctors, and microneedle patches are summarized. The potentials and application of each format are critically discussed, and some limitations are highlighted. Finally, how hydrogels can enable an “all-in-one platform” to play a key role in cancer therapy, regenerative medicine, and the treatment of inflammatory, degenerative, genetic, and metabolic diseases is being looked forward to.  相似文献   
29.
In this paper, a novel recessed gate metal–semiconductor field-effect transistor (RG-MESFET) is presented by modifying the depletion region and the electric field. The proposed structure improves the breakdown voltage, drain current and high frequency characteristics by embedding a lateral insulator region between drain and gate while is placed laterally into the metal gate and a silicon well exactly under the insulator region. We called this new structure as modified recess gate MESFET (MRG-MESFET). The radio frequency and direct current (DC) characteristics of the proposed structure is studied using numerical simulations and compared with a conventional MESFET (C-MESFET). The breakdown voltage, drain current DC transconductance and maximum power density of the proposed structure increase by 27%, 16.5%, 15% and 48%, respectively, relative to the C-MESFET. Also, the gate-source capacitance and the minimum noise figure of the proposed structure improve relative to the C-MESFET. The proposed structure can be used for high breakdown voltage, high saturation drain current, high DC transconductance, high power, high frequency, and low noise applications.  相似文献   
30.
A generalized cubic equation of state which can represent all the cubic equations is introduced and thermodynamic property relations for it are presented. Five cubic equations of states with respective mixing rules are used to predict molar volumes and vapor pressures of pure alkanes (from methane till n-tritriacontane) and solubilities of solid wax components (high molecular weight alkanes) in supercritical solvents. They are the RK (Redlich-Kwong), MMM (Mohsennia-Modarress-Mansoori), RM (Riazi-Mansoori), PR (Peng-Robinson), and SRK (Soave-Redlich-Kwon) equations of state. The experimental data necessary to compare the equations of state are taken from the literature. It is demonstrated that the SRK equation of state is more accurate for predicting vapor pressures of alkanes. The RM equation of state is shown to be more accurate for predicting molar volumes of saturated and sub-cooled liquid alkanes as well as molar volumes of alkanes in their supercritical condition. For the solubility of wax components in supercritical solvents it is shown that the MMM equation of state gives the least AAD% for the 270 data points of 10 binary systems studied consisting of a high molecular weight alkane and supercritical ethane and carbon dioxide.  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