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   862056篇
  免费   70575篇
  国内免费   1839篇
耳鼻咽喉   12799篇
儿科学   24625篇
妇产科学   25097篇
基础医学   124210篇
口腔科学   25488篇
临床医学   75316篇
内科学   164568篇
皮肤病学   16973篇
神经病学   70068篇
特种医学   35191篇
外国民族医学   171篇
外科学   136145篇
综合类   24603篇
现状与发展   2篇
一般理论   264篇
预防医学   66865篇
眼科学   20531篇
药学   64689篇
中国医学   1594篇
肿瘤学   45271篇
  2018年   7331篇
  2015年   7722篇
  2014年   11106篇
  2013年   16775篇
  2012年   22713篇
  2011年   23825篇
  2010年   13861篇
  2009年   13058篇
  2008年   22562篇
  2007年   24617篇
  2006年   24492篇
  2005年   24137篇
  2004年   23700篇
  2003年   22833篇
  2002年   21924篇
  2001年   35823篇
  2000年   36465篇
  1999年   30895篇
  1998年   9219篇
  1997年   8547篇
  1996年   8480篇
  1995年   8007篇
  1994年   7726篇
  1992年   26658篇
  1991年   26098篇
  1990年   25617篇
  1989年   24678篇
  1988年   23219篇
  1987年   22886篇
  1986年   21742篇
  1985年   21099篇
  1984年   16386篇
  1983年   13997篇
  1982年   8855篇
  1981年   8204篇
  1980年   7671篇
  1979年   16736篇
  1978年   12115篇
  1977年   10183篇
  1976年   9330篇
  1975年   10155篇
  1974年   12644篇
  1973年   12139篇
  1972年   11539篇
  1971年   10687篇
  1970年   10218篇
  1969年   9910篇
  1968年   8903篇
  1967年   8230篇
  1966年   7654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