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   52848篇
  免费   3228篇
  国内免费   313篇
耳鼻咽喉   561篇
儿科学   1488篇
妇产科学   1331篇
基础医学   5570篇
口腔科学   1838篇
临床医学   4784篇
内科学   11404篇
皮肤病学   1018篇
神经病学   3190篇
特种医学   1676篇
外国民族医学   8篇
外科学   8857篇
综合类   1278篇
现状与发展   3篇
一般理论   41篇
预防医学   3791篇
眼科学   1902篇
药学   4330篇
  1篇
中国医学   443篇
肿瘤学   2875篇
  2024年   65篇
  2023年   622篇
  2022年   1609篇
  2021年   2526篇
  2020年   1586篇
  2019年   1982篇
  2018年   2421篇
  2017年   1749篇
  2016年   1870篇
  2015年   1987篇
  2014年   2542篇
  2013年   3050篇
  2012年   4469篇
  2011年   4407篇
  2010年   2501篇
  2009年   2096篇
  2008年   3151篇
  2007年   3114篇
  2006年   2725篇
  2005年   2403篇
  2004年   2116篇
  2003年   1771篇
  2002年   1542篇
  2001年   418篇
  2000年   366篇
  1999年   341篇
  1998年   248篇
  1997年   176篇
  1996年   185篇
  1995年   143篇
  1994年   113篇
  1993年   110篇
  1992年   172篇
  1991年   178篇
  1990年   152篇
  1989年   146篇
  1988年   127篇
  1987年   111篇
  1986年   107篇
  1985年   134篇
  1984年   109篇
  1983年   70篇
  1982年   69篇
  1981年   65篇
  1980年   53篇
  1979年   62篇
  1978年   50篇
  1976年   45篇
  1974年   47篇
  1973年   44篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Abdominal Radiology - Metastatic involvement of the ovaries is not rare. The most common tumor types metastasizing to the ovaries, from non-gynecological organs, are breast, colorectal, gastric,...  相似文献   
12.
ABSTRACT

Purpose

To investigate the expression of IL-11 and its receptor IL-11Rα and to quantify density of CD163+ M2 macrophages in proliferative diabetic retinopathy (PDR).  相似文献   
13.
14.

Objective

Arch obstruction after the Norwood procedure is common and contributes to mortality. We determined the prevalence, associated factors, and practice variability of arch reintervention and assessed whether arch reintervention is associated with mortality.

Methods

From 2005 to 2017, 593 neonates in the Congenital Heart Surgeons' Society Critical Left Heart Obstruction cohort underwent a Norwood procedure. Median follow-up was 3.7 years. Multivariable parametric models, including a modulated renewal analysis, were performed.

Results

Of the 593 neonates, 146 (25%) underwent 218 reinterventions for arch obstruction after the Norwood procedure: catheter-based (n = 168) or surgical (n = 50) at a median age of 4.3 months (quartile 1-quartile 3, 2.6-5.7). Interdigitation of the distal aortic anastomosis was protective against arch reintervention. Development of ≥ moderate tricuspid valve regurgitation and right ventricular dysfunction at any point was associated with arch reintervention. Nonsignificant variables for arch reintervention included shunt type and preoperative aortic measurements. Surgical arch reintervention was protective against arch reintervention, but transcatheter reintervention was associated with increased reintervention. Arch reintervention was not associated with increased mortality. There was wide institutional variation in incidence of arch reintervention (range, 0-40 reinterventions per 100 years patient follow-up) and in preintervention gradient (range, 0-64 mm Hg).

Conclusions

Interdigitation of the distal aortic anastomosis during the Norwood procedure decreased the risk of arch reintervention. Surgical arch reintervention is more definitive than transcatheter. Arch reintervention after the Norwood procedure is not associated with increased mortality. Serial surveillance for arch obstruction, integrated with changes in right ventricular function and tricuspid valve regurgitation, is recommended after the Norwood procedure to improve outcomes.  相似文献   
15.
16.
17.
The present investigation was aimed at studying the possible role of curcumin against N-nitrosodiethylamine (NDEA)-induced toxicity in albino rats. Administration of NDEA to rats at a concentration of 0.1 mg/ml in drinking water ad libitum for 21 days produced toxicity in them, which was evident from histopathological changes in the rat livers, and increased levels of blood serum enzyme markers, i.e. aspartate transaminase, alanine transaminase, alkaline phosphatase, and lactate dehydrogenase. In addition, the levels of oxidative stress markers like lipid peroxidation (LPO), protein carbonyl (PCC), and glutathione-S-transferase (GST) activity were elevated and the total glutathione (GSH) content was reduced in the livers. The administration of curcumin to rats at concentrations of 10, 20, and 40 mg/ml in drinking water along with 0.1 mg/ml of NDEA for 21 days effectively suppressed NDEA-induced toxicity and also resulted in a dose-dependent reduction in the levels of blood serum enzyme markers (AST, ALT, ALP, and LDH). Moreover, LPO, PCC, and GST activity were reduced and the GSH level was increased upon the administration of curcumin along with NDEA. The results obtained for the comet assay in rat hepatocytes and blood lymphocytes showed a significant dose-dependent decrease in the mean tail length. The micronucleus assay performed on rat hepatocytes also showed a dose-dependent reduction in the frequency of micronucleated cells along with curcumin administration. These results suggest that curcumin has a protective role against NDEA-induced toxicity in albino rats.  相似文献   
18.
19.
20.
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