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   862343篇
  免费   70631篇
  国内免费   1839篇
耳鼻咽喉   12802篇
儿科学   24651篇
妇产科学   25102篇
基础医学   124299篇
口腔科学   25487篇
临床医学   75319篇
内科学   164620篇
皮肤病学   16975篇
神经病学   70092篇
特种医学   35195篇
外国民族医学   171篇
外科学   136231篇
综合类   24613篇
现状与发展   2篇
一般理论   263篇
预防医学   66891篇
眼科学   20525篇
药学   64709篇
中国医学   1594篇
肿瘤学   45272篇
  2018年   7337篇
  2015年   7727篇
  2014年   11107篇
  2013年   16789篇
  2012年   22722篇
  2011年   23835篇
  2010年   13867篇
  2009年   13065篇
  2008年   22583篇
  2007年   24629篇
  2006年   24502篇
  2005年   24148篇
  2004年   23709篇
  2003年   22835篇
  2002年   21940篇
  2001年   35830篇
  2000年   36481篇
  1999年   30902篇
  1998年   9223篇
  1997年   8550篇
  1996年   8479篇
  1995年   8007篇
  1994年   7730篇
  1992年   26671篇
  1991年   26105篇
  1990年   25626篇
  1989年   24689篇
  1988年   23229篇
  1987年   22887篇
  1986年   21746篇
  1985年   21110篇
  1984年   16397篇
  1983年   14004篇
  1982年   8866篇
  1981年   8209篇
  1980年   7677篇
  1979年   16743篇
  1978年   12121篇
  1977年   10189篇
  1976年   9333篇
  1975年   10151篇
  1974年   12645篇
  1973年   12140篇
  1972年   11542篇
  1971年   10688篇
  1970年   10221篇
  1969年   9916篇
  1968年   8907篇
  1967年   8233篇
  1966年   7657篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
We studied the role of theophylline on outcome of status epilepticus (SE) in children. During a two-year-period, 16 of 114 episodes of SE occurred in children receiving theophylline. At the onset of SE, theophylline blood levels were elevated in 8 episodes, and were therapeutic or subtherapeutic in 8 episodes. In the 8 episodes of SE with elevated theophylline levels, one child died and three suffered permanent new neurologic deficits. In the 8 episodes of SE with normal or low theophylline levels, only one child had a transient deficit. The occurrence of death or disability in 4 of 8 episodes of SE with elevated theophylline was considerably higher than the 23% incidence of death or persistent CNS deficit in the overall series of 114 episodes of SE. We conclude that theophylline, at toxic levels, is a significant factor in increased morbidity. We suspect that the hypoxia from the respiratory disorder for which theophylline was used, and the reduced cerebral blood flow known to occur with theophylline led to a failure to compensate for the increased cerebral metabolic rate of SE, thus increasing the risk of a poor outcome.  相似文献   
993.
A 21-year-old woman is reported with aplastic anaemia, who presented with pain in the leg. Rapid loss of sciatic nerve function followed. MRI showed irregular streaks of low intensity in the muscles of the pelvic region. A diagnosis of sciatic neuritis as initial symptom of clostridial myonecrosis was made.  相似文献   
994.
Using the unique resources of the Rochester Epidemiology Project for population-based studies, we identified 629 Olmsted County, Minn., residents who fulfilled the 1988 International Headache Society criteria for newly diagnosed migraine over a 3-year period. Over 6,400 patient records from several diagnostic rubrics were screened; a substantial proportion of cases had been 'signed-out' to diagnoses other than 'migraine headache'. Medical records were reviewed by two trained nurses who abstracted supporting data for two neurologists. The neurologists determined whether each case met eligibility requirements and assigned a headache diagnosis by consensus. The diagnostic criteria offered some flexibility and were adapted to retrospective record-based research. Most records contained enough information to effectively classify the headache, although information on the frequency and duration of attacks proved to be problematic. A validation re-abstraction of a 10% sample of cases was undertaken with acceptable reproducibility of symptoms and diagnosis. Our study shows that migraine headache can be studied retrospectively through existing detailed medical records.  相似文献   
995.
The numb chin.     
An apparently innocuous complaint such as a numb chin may be associated with malignant disease, either as heralding symptom or as a manifestation of metastasis. A series of 15 patients with numbness of the chin is presented in which a malignancy was diagnosed prior to the numbness. The numbness diminished or disappeared in 66% of the patients following either systemic chemotherapy or radiotherapy.  相似文献   
996.
The cause of Alzheimer's disease is unknown. Several factors have been proposed including head trauma. At present, the link between head injury and a subsequent neurodegenerative process is largely circumstantial, except in the case of dementia pugilistica (punch drunk syndrome) found in boxers. Recent studies have shown that the brains of boxers with this syndrome contain large numbers of 'diffuse' beta-protein immunoreactive plaques. We supposed that this plaque type might be associated with trauma induced Alzheimer-like degeneration. In order to test this hypothesis we have re-investigated a previously reported case of post-traumatic premature Alzheimer's disease. Immunocytochemistry using antibodies to amyloid beta-protein revealed large numbers of 'diffuse' non-Congophilic plaques with little or no neuritic component. A similar preponderance of this plaque type is present in the brains of boxers with dementia pugilistica. Our observations support the idea of a trauma induced Alzheimer-like degenerative process and indicate that such a condition is associated with a marked preponderance of 'diffuse' plaques.  相似文献   
997.
998.
999.
Immunosuppression observed even in the earliest laryngeal cancers can be, in part, reversed with H2 histamine antagonists. In an effort to explain this, we tested whether histamine could evoke changes in endogenous antitumor lymphokine production using tonsil lymphocytes as test cells. We have observed that lymphocytes, treated in vitro with histamine, display a significant suppression of lymphokine production and mixed lymphocyte proliferation response following galactose oxidase treatment. Interferon gamma production was reduced to less than 2% of control value in the presence of histamine. In contrast, the lymphokine-activated killer cell activity induced by purified, natural interleukin-2 was not affected by similar concentrations of histamine. Histamine appears to exert its inhibitory effect by stimulating the production of a substance released by suppressor T cells. The suppressive effects observed could be reversed by concomitant or sequential treatment with cimetidine or ranitidine and not by H1 histamine antagonists, indicating that it occurs through an H2 histamine receptor. These experiments suggest that histamine may have a profound suppressive effect on the lymphocyte population studied.  相似文献   
1000.
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