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   595篇
  免费   2篇
  国内免费   2篇
电工技术   3篇
综合类   8篇
化学工业   4篇
机械仪表   1篇
建筑科学   4篇
矿业工程   1篇
轻工业   1篇
武器工业   1篇
无线电   7篇
一般工业技术   1篇
冶金工业   566篇
自动化技术   2篇
  2018年   1篇
  2014年   1篇
  2008年   1篇
  2007年   1篇
  2004年   6篇
  2003年   3篇
  2002年   6篇
  2001年   4篇
  2000年   3篇
  1999年   20篇
  1998年   173篇
  1997年   72篇
  1996年   54篇
  1995年   39篇
  1994年   27篇
  1993年   36篇
  1992年   3篇
  1991年   7篇
  1990年   6篇
  1989年   8篇
  1988年   10篇
  1987年   15篇
  1986年   10篇
  1985年   7篇
  1983年   3篇
  1982年   3篇
  1981年   3篇
  1980年   5篇
  1979年   1篇
  1978年   2篇
  1977年   24篇
  1976年   41篇
  1975年   1篇
  1955年   3篇
排序方式: 共有599条查询结果,搜索用时 781 毫秒
591.
Indirect arterial blood pressure was determined on 33 horses prior to surgical intervention for the diagnosis and/or correction of acute abdominal disorders and a relationship between low systolic blood pressure and non-survival was established. It is suggested that blood pressure determination should be used to augment other methods of clinical and laboratory examination in cases of equine colic.  相似文献   
592.
A 49-year-old normotensive man died after a series of strokes, slowly evolving dementia and personality change occurring over a period of 23 years. CT scan showed large infarcts involving the cortex and white matter of the temporo-occipital areas, small subcortical infarcts and low attenuation in the white matter of the frontal and parietal lobes. Neuropathological examination revealed large cortical and small subcortical infarcts corresponding to the radiological findings as well as degeneration/demyelination of central white matter corresponding to the areas of low attenuation seen on CT. The basic underlying pathological process was hyaline arteriosclerosis and atheroma which diffusely affected the small intracerebral arteries and to a lesser extent the arteries of the circle of Willis. Though usual because of the absence of hypertension, the very early age at onset of the syndrome and the presence of large cortical infarcts this case illustrates the clinical, radiological and neuropathological features of subcortical arteriosclerotic encephalopathy (Binswanger's type).  相似文献   
593.
594.
We studied respiratory mechanics in young volunteers before and after 5-wk training programs limited to the ventilatory muscles. Four strength trainers (S) performed repeated static maximum inspiratory and expiratory maneuvers against obstructed airways. Four endurance trainers (E) performed voluntary normocarbic hyperpnea to exhaustion. Subjects spent 30-45 min each day in these exercises, 5 days a week. Four control subjects (C) did no training. We attempted to minimize the effect of learning. S increased pressure maximums by about 55%, but vital capacity and total lung capacity by only about 4%. Initially all subjects could sustain hyperpnea at about 81% of their control 15-s maximum voluntary ventilation (MVV) for 15 min; E increased this to about 96% and increased their MVV by 14% as well. No other statistically significant changes were recognized in any group. We conclude that ventilatory muscle strength or endurance can be specifically increased by appropriate ventilatory muscle training programs.  相似文献   
595.
596.
597.
The clinicopathologic findings in an eye from a 40-year-old man with essential iris atrophy are reported. Noteworthy is the proliferation of corneal endothelium and a laying down of a new Descemet (cuticular) membrane over the trabecular meshwork and in areas of anterior peripheral synechiae formation over the pseudoangle. The histologic characteristics favor a vascular cause for the condition, but the evidence is circumstantial.  相似文献   
598.
Fifty-nine children with pulmonary atresia and intact ventricular septum underwent various forms of surgical treatment at the Hospital for Sick Children, Toronto, during 1950 to mid 1975. Twenty-three patients had pulmonary valvotomy, 15 direct, 2 indirect, and 6 both direct valvotomy and infundibulectomy. All died, 19 early and 4 late. Of 13 patients who received a systemic-pulmonary artery shunt, 4 combined with surgical atrial septectomy, there are only 2 long-term survivors both of whom were children who had had a Waterston anastomosis. Recently we have been treating infants with small right ventricles with balloon atrial septostomy at cardiac catherterization followed by a Potts anastomosis and pulmonary valvotomy. If the Potts anastomosis appears satisfactory the persistent ductus arteriosus is ligated. This scheme was used in 23 infants, with 4 early deaths and 2 late deaths. Of 17 survivors, further shunts were required in 4 children. One child has had a formal repair, with insertion of valves in both tricuspid and pulmonary areas. We believe that this operative combination of Potts anastomosis and pulmonary valvotomy offers the infant with pulmonary atresia and a small right ventricle a relatively low initial mortality and the possibility of right ventricular enlargement and subsequent repair.  相似文献   
599.
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