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   2384086篇
  免费   172394篇
  国内免费   4396篇
耳鼻咽喉   35261篇
儿科学   77449篇
妇产科学   67348篇
基础医学   335953篇
口腔科学   67962篇
临床医学   205224篇
内科学   469484篇
皮肤病学   53096篇
神经病学   188181篇
特种医学   95389篇
外国民族医学   1056篇
外科学   368176篇
综合类   53662篇
现状与发展   7篇
一般理论   769篇
预防医学   172572篇
眼科学   55147篇
药学   178819篇
  6篇
中国医学   5009篇
肿瘤学   130306篇
  2018年   22706篇
  2016年   19388篇
  2015年   21943篇
  2014年   30688篇
  2013年   46914篇
  2012年   63169篇
  2011年   66926篇
  2010年   39985篇
  2009年   38390篇
  2008年   64131篇
  2007年   69402篇
  2006年   69893篇
  2005年   67968篇
  2004年   66431篇
  2003年   64402篇
  2002年   63328篇
  2001年   113927篇
  2000年   117733篇
  1999年   99937篇
  1998年   27009篇
  1997年   24456篇
  1996年   24282篇
  1995年   22985篇
  1994年   21601篇
  1993年   20168篇
  1992年   78400篇
  1991年   76327篇
  1990年   74527篇
  1989年   72057篇
  1988年   66779篇
  1987年   65808篇
  1986年   62202篇
  1985年   59294篇
  1984年   44495篇
  1983年   37622篇
  1982年   22165篇
  1981年   20195篇
  1979年   41404篇
  1978年   29130篇
  1977年   25056篇
  1976年   23017篇
  1975年   25690篇
  1974年   30244篇
  1973年   29248篇
  1972年   27636篇
  1971年   25514篇
  1970年   24168篇
  1969年   22749篇
  1968年   21079篇
  1967年   18919篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
92.
OBJECTIVE: Gelastic seizures are a frequent and well established manifestation of the epilepsy associated with hypothalamic hamartomas. The scalp EEG recordings very seldom demonstrate clear spike activity and the information about the ictal epilepsy dynamics is limited. In this work, we try to isolate epileptic rhythms in gelastic seizures and study their generators. METHODS: We extracted rhythmic activity from EEG scalp recordings of gelastic seizures using decomposition in independent components (ICA) in three patients, two with hypothalamic hamartomas and one with no hypothalamic lesion. Time analysis of these rhythms and inverse source analysis was done to recover their foci of origin and temporal dynamics. RESULTS: In the two patients with hypothalamic hamartomas consistent ictal delta (2-3 Hz) rhythms were present, with subcortical generators in both and a superficial one in a single patient. The latter pattern was observed in the patient with no hypothalamic hamartoma visible in MRI. The deep generators activated earlier than the superficial ones, suggesting a consistent sub-cortical origin of the rhythmical activity. CONCLUSIONS: Our data is compatible with early and brief epileptic generators in deep sub-cortical regions and more superficial ones activating later. SIGNIFICANCE: Gelastic seizures express rhythms on scalp EEG compatible with epileptic activity originating in sub-cortical generators and secondarily involving cortical ones.  相似文献   
93.
Aggressive behavior linked to corticotropin-reactive autoantibodies.   总被引:3,自引:0,他引:3  
BACKGROUND: Altered stress response is characteristic for subjects with abnormal aggressive and antisocial behavior, but the underlying biological mechanisms are unclear. We hypothesized that autoantibodies (autoAbs) directed against several stress-related neurohormones may exist in aggressive subjects. METHODS: Using enzyme-linked immunosorbent assay, we studied whether autoAbs directed against corticotropin (ACTH), alpha-melanocyte-stimulating hormone (alpha-MSH), oxytocin, and vasopressin are present in serum of male subjects with conduct disorder and prisoners with history of violence. Healthy blood donors served as control subjects. RESULTS: Both conduct disorder and prisoners groups displayed strongly increased levels of ACTH-reactive immunoglobulin G (IgG) and immunoglobulin M (IgM) autoAbs compared with control subjects. Levels of oxytocin-reactive IgM autoAbs were slightly increased in both groups of aggressive subjects, whereas levels of vasopressin-reactive IgG and IgM autoAbs were lower only in conduct disorder. No differences in the levels of alpha-MSH-reactive autoAbs were found between aggressive and control subjects. CONCLUSIONS: High levels of ACTH-reactive autoAbs as well as altered levels of oxytocin- and vasopressin-reactive autoAbs found in aggressive subjects may interfere with the neuroendocrine mechanisms of stress and motivated behavior. Our data suggest a new biological mechanism of human aggressive behavior that involves autoAbs directed against several stress-related neurohormones.  相似文献   
94.
AIM: The intention was to investigate cerebrospinal fluid pressure (CSFP) and volume of cerebrospinal fluid (CSF) drained during and after thoracic- and thoracoabdominal aneurysm repair. The findings were related to the occurrence of postoperative neurologic deficits. METHODS: Twenty-nine patients (12 with thoracic and 17 with thoracoabdominal aortic aneurysm) were operated without shunting or extracorporeal circulation. For monitoring of CSFP an intrathecal catheter was placed in all patients. The volume of CSF withdrawn intraoperatively, on the day of operation as well as on the 1st and 2nd postoperative day was recorded. RESULTS: Twenty-six patients had no postoperative neurologic sequelae. One patient had postoperative paraplegia while 2 had paraparesis. The three patients with neurologic sequelae had higher CSFP intraoperatively than those without neurologic symptoms (P=0.04). Median CSFP during aortic cross-clamping was 19 mmHg and 10 mmHg and the median volumes of CSF drained on the day of operation 210 and 85 mL in the two groups, respectively. There was a significant positive correlation between CSFP and central venous pressure. CONCLUSIONS: A higher intraoperative CSFP was observed in patients with neurologic sequelae following thoracic- and thoracoabdominal aneurysm repair. Further, there was a tendency of higher volumes of CSF drained in this group of patients. Although, the series is too small to allow firm conclusions, it supports the view that CSFP monitoring and drainage is beneficial during thoracic- and thoracoabdominal aneurysm repair.  相似文献   
95.
96.
97.
98.
Primary chemotherapy administered to breast cancer patientsis the best model to identify baseline features able to predictwhich patients may be most likely to benefit or not from a cytotoxicregimen. In the March issue of Annals of Oncology two papersevaluated the predictive role of immunohistochemical p53 expressionon  相似文献   
99.
100.
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