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   105篇
  免费   2篇
电工技术   2篇
化学工业   14篇
机械仪表   1篇
水利工程   2篇
石油天然气   1篇
无线电   7篇
一般工业技术   16篇
冶金工业   61篇
自动化技术   3篇
  2023年   2篇
  2021年   2篇
  2018年   1篇
  2015年   2篇
  2013年   1篇
  2012年   3篇
  2011年   1篇
  2010年   2篇
  2009年   1篇
  2008年   5篇
  2007年   2篇
  2006年   1篇
  2005年   1篇
  2004年   4篇
  2003年   1篇
  2002年   2篇
  2001年   1篇
  2000年   1篇
  1998年   22篇
  1997年   8篇
  1996年   4篇
  1995年   8篇
  1994年   3篇
  1993年   4篇
  1991年   2篇
  1988年   1篇
  1987年   1篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
  1980年   3篇
  1979年   1篇
  1977年   1篇
  1976年   4篇
  1965年   4篇
排序方式: 共有107条查询结果,搜索用时 15 毫秒
11.
It has been established that GABAA and GABAB receptors can exist separately and/or co-exist in the membrane of dorsal root ganglion neurons. In our previous investigation it has been shown that co-existence of these two kinds of receptors is about 80% of the neurons examined (20/25). The present study was aimed to explore whether the activation of these two kinds of receptors could interact with each other using intracellular and whole-cell patch-clamp recordings. Baclofen, a specific GABAB receptor agonist, was found to exert negative modulatory effects on the responses mediated by GABAA receptor. In experiments with intracellular recording, GABA (0.3-1000 microM)- and muscimol (100-1000 microM)-induced depolarization was attenuated markedly and reversibly by preapplication of baclofen (100 microM) (15/21 and 17/21, respectively). In whole-cell patch-clamp recordings GABA (100 microM) and two specific GABAA receptor agonists, muscimol (10 microM) and isoguvacine (50 microM), activated currents were inhibited markedly by preapplication of baclofen 30 s or more and the inhibition was concentration dependent (1-100 microM baclofen) and reversible. The possible mechanisms underlying the inhibition by baclofen of the responses mediated by GABAA receptor and the physiological significance implicated are discussed.  相似文献   
12.
PURPOSE: The 2 types of urethral injury that can occur during circumcision are urethrocutaneous fistula and urethral distortion secondary to partial glans amputation. We report the surgical repair of these rare injuries. MATERIALS AND METHODS: In 8 patients urethrocutaneous fistulas located on the distal penile shaft or at the coronal margin were managed by splitting the glans and using a Mathieu style skin flap in 4 or vascularized penile skin flap in 4 to bridge the urethral defect. Three patients underwent repair of a hypospadiac deviated urethra secondary to partial glans amputation by 1 cm. of urethral mobilization and repositioning the meatus into a terminal position within the remaining glans tissue. RESULTS: The 8 patients with urethrocutaneous fistulas voided via a terminal meatus without fistula recurrence at a mean followup of 3.2 years (range 1 to 6). The 3 patients with partial glans amputation and urethral deviation repaired by short urethral advancement had functionally acceptable results, defined as a normal urinary stream, although 1 required meatal dilation postoperatively. CONCLUSIONS: The 2 types of urethral injuries that can occur during circumcision are a subcoronal urethrocutaneous fistula and scarred abnormal urethra from partial glans amputation. The urethrocutaneous fistula can be successfully repaired by splitting the glans and forming a neourethra from a vascularized pedicle flap of penile skin. The abnormal urethra after partial glans amputation is more difficult to repair but repositioning the urethra in a more cosmetic location has restored function.  相似文献   
13.
14.
15.
16.
The subroutine call is one of the most fundamental of program control constructs. Despite this, it is rarely implemented at the job control or task level in existing commercially available software systems. When the feasibility of adding a general program calling mechanism to an existing system was investigated, it was apparent that there exist constraints on the amount of state information which could be saved on behalf of the calling program. A mechanism with low run-time overhead which saves a minimal amount of state information has proven to be easily integratable into a commercially available operating system. This mechanism has had a significant impact on the ease of development and support of large systems of programs. Examples of the use of the new calling mechanism include a program development system and a recursive directory manager for hierarchical directories.  相似文献   
17.
In the past six years, 35 patients with thermal injuries have died with a diagnosis of endocarditis. The cause of death in 21 of the 22 patients with acute bacterial endocarditis (ABE) was directly related to complications arising from the ongoing sepsis. In only three cases was the diagnosis considered pre-mortem. The endocarditis was located in the right heart in 18, left heart in 9, and both sides in 8 cases. Associated venous thrombi were present in 14 instances, and 10 of these were septic thrombi. Staphylococcus was the primary organism in the blood in 17 of 22 patients with ABE. Clinically audible murmurs were present in only two patients. In no instance was ABE superimposed upon previously existing valvular disease. ABE can serve as a silent source of sepsis in the burn patient. The diagnosis should be suspected with persistantly positive blood cultures, especially for Staphylococcus aureus, in any burn patient in whom no other foci of sepsis can be identified. Vigorous methods of diagnosis and specific treatment are recommended.  相似文献   
18.
19.
In an emergency, intravenous access may be difficult to obtain rapidly. Alternate routes of administration for drugs are, therefore, desirable. Our study was performed to determine if naloxone could be efficacious in reversing morphine-induced respiratory depression in rabbits when administered using the endotracheal route. Our results indicate that naloxone administered in this fashion is effective in reversing morphine-induced respiratory depression in the rabbit. Mean minute ventilation was depressed to greater than half of resting baseline levels using morphine sulfate. Endotracheally administered naloxone reversed this respiratory depression and resulted in a greater than five-fold increase in mean minute ventilation above baseline levels. We concluded that endotracheal naloxone is efficacious in reversing morphine-induced respiratory depression in the rabbit. The endotracheal route may be an effective alternative for naloxone administration in man when rapid intravenous access is not obtainable.  相似文献   
20.
Park HS  Baskin JS  Kwon OH  Zewail AH 《Nano letters》2007,7(9):2545-2551
In this contribution, we report the development of ultrafast electron microscopy (UEM) with atomic-scale real-, energy-, and Fourier-space resolutions. This second-generation UEM provides images, diffraction patterns, and electron energy spectra, and here we demonstrate its potential with applications for nanostructured materials and organometallic crystals. We clearly resolve the separation between atoms in the direct images and the Bragg spots/Debye-Scherrer rings in diffraction and obtain the electronic structure and elemental energies in the electron energy loss spectra (EELS) and energy filtered transmission electron microscopy (EFTEM).  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