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   146篇
  免费   7篇
电工技术   1篇
化学工业   40篇
金属工艺   5篇
机械仪表   4篇
能源动力   14篇
轻工业   20篇
无线电   11篇
一般工业技术   14篇
冶金工业   21篇
自动化技术   23篇
  2023年   4篇
  2022年   4篇
  2021年   11篇
  2020年   4篇
  2019年   3篇
  2018年   7篇
  2017年   8篇
  2016年   8篇
  2015年   4篇
  2014年   6篇
  2013年   5篇
  2012年   2篇
  2011年   6篇
  2010年   7篇
  2009年   8篇
  2008年   11篇
  2007年   13篇
  2006年   1篇
  2005年   6篇
  2004年   5篇
  2003年   3篇
  2002年   4篇
  2001年   1篇
  2000年   1篇
  1998年   8篇
  1997年   2篇
  1996年   4篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1991年   1篇
  1986年   1篇
  1985年   2篇
排序方式: 共有153条查询结果,搜索用时 15 毫秒
41.
A 24-year-old woman was admitted to our hospital due to moderate asthmatic attacks. Dyspnea and hypoxemia progressed gradually despite medication. A chest roentgenogram revealed left unilateraly hyperlucency with pneumomediastiumn and subcutaneous emphysema. Swyer-James syndrome was diagnosed. Several cases of Swyer-James syndrome with bronchial asthma airway hyperresponsiveness have been reported, but we know of no reports of Swyer-James syndrome with pneumomediastinum and subcutaneous emphysema due to prolonged asthmatic attacks. Pneumomediastinum and subcutaneous emphysema may be caused by abnormally high pressures in the bronchial lumen and alveolar space during asthmatic attacks, because the emphysematous lesion may be structurally weak.  相似文献   
42.
43.
The effects of extracellular magnesium concentration ([Mg2+]ex) on thyrotropin-releasing hormone (TRH)-stimulated intracellular free calcium mobilization and prolactin secretion were investigated concomitantly with measurement of the intracellular free magnesium concentration ([Mg2+]i). TRH-stimulated intracellular free calcium mobilization was significantly inhibited when the medium was replaced by high Mg2+ medium ([Mg2+]ex = 10 mM) in normal Ca2+ medium. The inhibitory effects of high Mg2+ became apparent concomitantly with an increase in [Mg2+]i from 0.7 to 1.3 mM. High Mg2+ significantly inhibited TRH-induced PRL secretion in a dose-dependent manner in normal Ca2+ medium. TRH-stimulated inositol triphosphate (IP3) production was rather augmented by the replacement with high Mg2+ medium. In summary, high Mg2+ inhibits Ca2+ influx stimulated by TRH in the rat pituitary lactotropes, possibly with the involvement of [Mg2+]i increase. These results have general importance in relation to high Mg(2+)-induced suppression of the biological functions of cells.  相似文献   
44.
A control method that makes the head of a snake robot follow an arbitrary trajectory on two non-parallel planes, including coexisting sloped and flat planes, is presented. We clarify an appropriate condition of contact between the robot and planes and design a controller for the part of the robot connecting the two planes that satisfies the contact condition. Assuming that the contact condition is satisfied, we derive a simplified model of the robot and design a controller for trajectory tracking of the robot’s head. The controller uses kinematic redundancy to avoid violating the limit of the joint angle and a collision between the robot and the edge of a plane. The effectiveness of the proposed method is demonstrated in experiments using an actual robot.  相似文献   
45.
An in situ experimental technique was developed for detecting structure changes at the electrode/electrolyte interface of lithium cell using synchrotron X-ray reflectometry and two-dimensional model electrodes with a restricted lattice plane. The electrode was constructed with an epitaxial film of LiNi0.8Co0.2O2 synthesized by the pulsed laser deposition method. The orientation of the epitaxial film depends on the substrate plane; the 2D layer of LiNi0.8Co0.2O2 is parallel to the SrTiO3 (1 1 1) substrate ((003)LiCo0.2Ni0.8O2//(111)SrTiO3), while the 2D layer is perpendicular to the SrTiO3 (1 1 0) substrate ((110)LiCo0.2Ni0.8O2//(110)SrTiO3). These films provided an ideal reaction field suitable for detecting structure changes at the electrode/electrolyte interface during the electrochemical reaction. The X-ray reflectometry indicated a formation of a thin-film layer at the LiNi0.8Co0.2O2 (1 1 0)/electrolyte interface during the first charge-discharge cycle, while the LiNi0.8Co0.2O2 (0 0 3) surface showed an increase in the surface roughness without forming the surface thin-film layer. The reaction mechanism at the electrode/electrolyte interface is discussed based on our new experimental technique for lithium batteries.  相似文献   
46.
Superhydrophobic materials that prevent unwanted liquid adhesion can easily lose this property because of limited mechanical durability despite topological/chemical control and/or robust material selection. Here, long‐lasting superhydrophobic coatings with a system to effectively detect and repair damaged areas with “liquid marble,” a droplet covered with hydrophobic nanoparticles, are reported. The particles prevent direct contact between the droplet and the substrate (Cassie state). However, they can adhere to the non‐superhydrophobic damaged area in response to the substrate wettability via an external force or an increase in liquid volume via penetration of the outer nanoparticle layer (Wenzel state). This Cassie–Wenzel transition thus induces self‐assembly of the nanoparticles onto the non‐superhydrophobic area in response to the wettability, restoring superhydrophobicity.  相似文献   
47.
48.
A novel adsorbent, Zr(IV)-immobilized resin, was prepared by surface template polymerization. This adsorbent, prepared by adding polystyrene (PS) to resin, has a high adsorption capacity for the removal of fluoride ion from aqueous solutions. The adsorption capacity increased with rising PS concentration, since the specific surface area can be effectively increased by adding polystyrene as a porogen. The adsorption isotherm has been modeled by the Langmuir and Freundlich equations. The adsorption isotherms were well described by the Langmuir equation. The removal of fluoride was also carried out using a column method. The presence of PS in the resin exerted a remarkable influence on the uptake of fluoride ion. The fluoride adsorbed on the resin was quantitatively eluted with 0.1 M NaOH.  相似文献   
49.
The transformation protocol can allow two players to share an unconditionally secure secret key using a random deal of cards. A sufficient condition on the number of cards for the transformation protocol to succeed was known. However, it has been an open problem to obtain a necessary and sufficient condition. This paper improves the transformation protocol and gives a necessary and sufficient condition for the resulting protocol to succeed. An early version of the paper was presented in Lecture Notes in Computer Science, vol. 3106.  相似文献   
50.
Electrification and levitation of particles in a continuous particle feed and dispersion system have been studied both theoretically and experimentally. This system consisted of a vibrator and inclined parallel electrodes. A mesh and a vibrating plate were used for the upper and lower electrodes, respectively. A dc voltage was applied to one of the electrodes and the other electrode was grounded. Particles fed to the lower electrode were charged by induction and levitated upward by the Coulomb forces. When the applied voltage was high enough, the particles passed through the mesh electrode. The charge of the particles was measured with a Faraday cup, and the particle behavior was observed with a high-speed microscope camera. The particle charges were also analyzed from experimentally obtained particle trajectories and numerically calculated electric fields. Finally, the conditions for the effective levitation and dispersion of the charged particles and their mechanisms were studied and have been described in detail.  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