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   901582篇
  免费   62664篇
  国内免费   2327篇
耳鼻咽喉   12492篇
儿科学   28728篇
妇产科学   26170篇
基础医学   126811篇
口腔科学   24738篇
临床医学   74954篇
内科学   183692篇
皮肤病学   19005篇
神经病学   71549篇
特种医学   36507篇
外国民族医学   336篇
外科学   142363篇
综合类   19078篇
一般理论   247篇
预防医学   64671篇
眼科学   20103篇
药学   64039篇
  11篇
中国医学   1799篇
肿瘤学   49280篇
  2018年   9082篇
  2017年   7193篇
  2016年   7713篇
  2015年   8764篇
  2014年   12405篇
  2013年   19253篇
  2012年   25720篇
  2011年   27315篇
  2010年   16603篇
  2009年   15805篇
  2008年   26172篇
  2007年   27786篇
  2006年   27974篇
  2005年   27503篇
  2004年   26343篇
  2003年   25510篇
  2002年   25107篇
  2001年   41394篇
  2000年   42602篇
  1999年   36311篇
  1998年   9979篇
  1997年   9169篇
  1996年   9098篇
  1995年   8456篇
  1994年   8094篇
  1993年   7598篇
  1992年   28236篇
  1991年   27008篇
  1990年   26442篇
  1989年   25375篇
  1988年   23577篇
  1987年   23191篇
  1986年   22283篇
  1985年   21173篇
  1984年   15826篇
  1983年   13496篇
  1982年   8101篇
  1979年   14605篇
  1978年   10233篇
  1977年   8637篇
  1976年   8167篇
  1975年   8966篇
  1974年   10716篇
  1973年   10192篇
  1972年   9677篇
  1971年   8932篇
  1970年   8598篇
  1969年   8034篇
  1968年   7692篇
  1967年   7096篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
73.
74.
Electrocardiographic symptoms were evaluated in 53 patients with an additional left-ventricular chorda (ALVC), detected by two-dimensional echocardiography. Signs of early ventricular repolarization (EVR) were identified in 45 (84.9%) patients. A transverse ALVC was more common in EVR-free patients (87.5%), as compared to patients with ALVC + EVR combinations (51.1%; p less than 0.05).  相似文献   
75.
76.
Noninvasive localized proton magnetic resonance spectroscopy (MRS) was used for differential diagnosis of a focal brain lesion in a 2.5-year-old girl. The clinical signs were a mild head tilt and neck pain. Magnetic resonance imaging (MRI) revealed a lesion in the right hemisphere of the cerebellum, but its nature remained obscure. In this lesion quantitative determinations of cerebral metabolites by fully relaxed, short-echo-time proton MRS revealed markedly lowered N-acetylaspartate (NAA) and pronounced elevations of choline-containing compounds (Cho) and myo-inositol (Ins), whereas metabolite concentrations in cortical gray matter and white matter were within normal ranges. The metabolite pattern of the lesion indicated loss of vital neuroaxonal tissue (low NAA) and enhanced glial proliferation (high Cho and Ins), which, together with the MRI morphology, suggested a brain tumor. The diagnosis was established by neurosurgical exploration and total extirpation of the tumor. Histology confirmed an astrocytoma (WHO II). After 2 weeks' recovery the child was discharged with no neurological signs.  相似文献   
77.
78.
79.
Background : Methimazole, an anti-thyroid drug, was recently found to be useful in the treatment of systemic lupus erythematosus and other autoimmune diseases. Moreover, decreased thyroid hormone production is associated with a variety of immunological manifestations, such as reduced activation of CD4+ cells, increased CD8+ cell activity and reduced soluble IL-2 receptors. In the present study we examined the effects of methimazole and propylthiouracil on a rat model of experimental colitis.
Methods : Colitis was induced by intracolonic administration of 30 mg trinitrobenzene sulphonic acid (TNB). Two weeks prior to induction of colitis, rats were treated by either methimaziole (0.04%) or propylthiouracil (0.01%) in drinking water after a week of free access to water. Rats were sacrificed 48 h or 7 days after induction of colitis. The colon was isolated, rinsed with ice-cold water and weighed. Damage was assessed both macroscopically and microscopically and myeloperoxidase (MPO) activity determined.
Results : All treated rats were hypothyroid as manifested by a significant elevation of thyroid stimulating hormone (TSH), by comparison with the control groups (mean -1.82±0.40 versus 0.11±0.02 mmol/L, respectively). The inflammatory response elicited by TNB resulted in severe mucosal damage 48 h after damage induction, which persisted for 7 days. Pre-treatment with either methimazole 0.04% or propylthiouracil 0.01% significantly decreased mucosal damage macroscopically (lesion area, lesion score and segmental weight) microscopically and also significantly decreased MPO level at both time points ( P <0.01).
Conclusions : Methimazole and propylthiouracil significantly reduce mucosal damage and colonic weight in a rat model of colitis. The mode by which they do so remains to be studied.  相似文献   
80.
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