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   1743257篇
  免费   127072篇
  国内免费   3949篇
耳鼻咽喉   22306篇
儿科学   56864篇
妇产科学   47037篇
基础医学   247331篇
口腔科学   49529篇
临床医学   156069篇
内科学   343243篇
皮肤病学   39279篇
神经病学   135834篇
特种医学   65412篇
外国民族医学   246篇
外科学   265259篇
综合类   39654篇
现状与发展   5篇
一般理论   593篇
预防医学   128688篇
眼科学   41222篇
药学   126635篇
  7篇
中国医学   4530篇
肿瘤学   104535篇
  2021年   13592篇
  2019年   14268篇
  2018年   20875篇
  2017年   15877篇
  2016年   17351篇
  2015年   19771篇
  2014年   27521篇
  2013年   39975篇
  2012年   55646篇
  2011年   58572篇
  2010年   34559篇
  2009年   32396篇
  2008年   54413篇
  2007年   57815篇
  2006年   58248篇
  2005年   55666篇
  2004年   53801篇
  2003年   50924篇
  2002年   49148篇
  2001年   92169篇
  2000年   93903篇
  1999年   77435篇
  1998年   20353篇
  1997年   17797篇
  1996年   17887篇
  1995年   17194篇
  1994年   15699篇
  1993年   14437篇
  1992年   57689篇
  1991年   55580篇
  1990年   53213篇
  1989年   51008篇
  1988年   46363篇
  1987年   45157篇
  1986年   42436篇
  1985年   40238篇
  1984年   29754篇
  1983年   25239篇
  1982年   14349篇
  1981年   12818篇
  1979年   25745篇
  1978年   17827篇
  1977年   15145篇
  1976年   14074篇
  1975年   14749篇
  1974年   17834篇
  1973年   17103篇
  1972年   15815篇
  1971年   14573篇
  1970年   13527篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
992.
Soluflazine, a specific adenosine transport inhibitor, was intracerebroventricularly administered to rats in a dose range of 10, 25, and 50 nmoles. At a dose of 50 nmoles, soluflazine decreased waking and increased sleep during the first hour of EEG recording. Our previous work has shown that chronic intracerebroventricular administration of soluflazine to rats decreased radioligand binding to adenosine A1 and A2 receptors in specific brain regions. The present data show that administration of an adenosine transport inhibitor to rats produces a transient hypnotic effect presumably through increases in synaptic adenosine levels.  相似文献   
993.
Despite current intensive research, the pathophysiology of tardive dyskinesia (TD), a serious neurological side effect of neuroleptic treatment, is poorly understood. Prompted by the observation of an increased incidence and severity of abnormal perioral movements in neuroleptic-treated pinealectomized, as compared to intact rats, we suggested that the pineal gland exerts a protective effect which mitigates against the development of TD and, by inference, that reduced melatonin secretion may be related to the pathophysiology of TD. To investigate this proposition further, we studied the association of TD with pineal calcification (PC) on CT scan in chronic schizophrenic patients. Our findings revealed a significant association between TD and PC and suggest, furthermore, that PC may be a neuroradiological marker of TD. Since PC may reflect diminished secretory activity of the gland, these findings support the hypothesis that the pathophysiology of TD is linked to disturbances of melatonin secretion. The clinical and therapeutic implications of these novel findings are discussed. In the following communication, in which we introduce the hypothesis that disturbances of 5-HT and melatonin secretion are related to the pathophysiology of TD. Subsequently, we present a series of studies which relate to the association of TD with PC. We conclude by presenting the hypothesis that disturbances in melatonin secretion may also be relevant to the pathophysiology of Tourette's syndrome.  相似文献   
994.
995.
The purpose of this study was to evaluate three subcutaneous injection sites for low-dose heparin therapy (5,000 units). One hundred and one subjects were randomly placed in one of three groups. Group A received injections in the abdomen, Group B, in the thigh, and Group C in the arm. Each subject received three injections at the one site. Activated partial thromboplastin time (APTT) was measured prior to initiation of heparin and again four hours after the first injection. Bruising was measured at 48, 60, and 72 hours postinjection. There were no statistically significant differences among groups for either changes in APTT or bruising at 60 and 72 hours postinjection. Thus the clinical practice of utilizing the abdomen as the only or preferred site for subcutaneous heparin injections was not supported.  相似文献   
996.
997.
Computed tomography (CT) was performed in 14 cases of tuberculous meningitis (TBM), 12 of which were examined during the acute phase of the disease. CT findings in these cases included internal hydrocephalus (6/12), internal combined with external hydrocephalus (2/12), focal lesions consistent with localized encephalitis (3/12), diffuse brain edema (1/12), and middle cerebral artery infarction (1/12). In comparison to 32 cases of nonspecific bacterial meningitis, internal hydrocephalus was found significantly more often in TBM than in nonspecific meningitis (p less than 0.01) making CT an additional tool for the differentiation of these conditions in doubtful cases. In addition, CT features of 2 cases of cerebral tuberculoma are presented.  相似文献   
998.

Background  

The telomeric region of mouse chromosome 12 has previously shown frequent allelic loss in murine lymphoma. The Bcl11b gene has been identified and suggested as a candidate tumor suppressor gene within this region. In this study, we aimed to elucidate whether Bcl11b is mutated in lymphomas with allelic loss, and whether the mutations we detected conferred any effect on cell proliferation and apoptosis.  相似文献   
999.
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