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   6341篇
  免费   354篇
  国内免费   33篇
耳鼻咽喉   165篇
儿科学   193篇
妇产科学   218篇
基础医学   1115篇
口腔科学   71篇
临床医学   457篇
内科学   1338篇
皮肤病学   173篇
神经病学   650篇
特种医学   83篇
外科学   520篇
综合类   32篇
一般理论   1篇
预防医学   549篇
眼科学   113篇
药学   660篇
中国医学   18篇
肿瘤学   372篇
  2023年   47篇
  2022年   208篇
  2021年   384篇
  2020年   150篇
  2019年   208篇
  2018年   207篇
  2017年   193篇
  2016年   208篇
  2015年   229篇
  2014年   264篇
  2013年   365篇
  2012年   545篇
  2011年   579篇
  2010年   284篇
  2009年   217篇
  2008年   328篇
  2007年   346篇
  2006年   366篇
  2005年   311篇
  2004年   272篇
  2003年   261篇
  2002年   232篇
  2001年   47篇
  2000年   48篇
  1999年   36篇
  1998年   27篇
  1997年   17篇
  1996年   22篇
  1995年   12篇
  1994年   17篇
  1992年   14篇
  1991年   12篇
  1989年   10篇
  1988年   13篇
  1987年   10篇
  1986年   11篇
  1985年   9篇
  1983年   10篇
  1980年   7篇
  1979年   17篇
  1976年   8篇
  1975年   15篇
  1974年   17篇
  1973年   18篇
  1972年   19篇
  1971年   15篇
  1970年   14篇
  1969年   11篇
  1968年   9篇
  1966年   8篇
排序方式: 共有6728条查询结果,搜索用时 31 毫秒
1.
2.
3.
Pulmonary hypertension of the newborn (PHN) constitutes a critical condition with severe cardiovascular and neurological consequences. One of its main causes is hypoxia during gestation, and thus, it is a public health concern in populations living above 2500 m. Although some mechanisms are recognized, the pathophysiological facts that lead to PHN are not fully understood, which explains the lack of an effective treatment. Oxidative stress is one of the proposed mechanisms inducing pulmonary vascular dysfunction and PHN. Therefore, we assessed whether melatonin, a potent antioxidant, improves pulmonary vascular function. Twelve newborn sheep were gestated, born, and raised at 3600 meters. At 3 days old, lambs were catheterized and daily cardiovascular measurements were recorded. Lambs were divided into two groups, one received daily vehicle as control and another received daily melatonin (1 mg/kg/d), for 8 days. At 11 days old, lung tissue and small pulmonary arteries (SPA) were collected. Melatonin decreased pulmonary pressure and resistance for the first 3 days of treatment. Further, melatonin significantly improved the vasodilator function of SPA, enhancing the endothelial‐ and muscular‐dependent pathways. This was associated with an enhanced nitric oxide‐dependent and nitric oxide independent vasodilator components and with increased nitric oxide bioavailability in lung tissue. Further, melatonin reduced the pulmonary oxidative stress markers and increased enzymatic and nonenzymatic antioxidant capacity. Finally, these effects were associated with an increase of lumen diameter and a mild decrease in the wall of the pulmonary arteries. These outcomes support the use of melatonin as an adjuvant in the treatment for PHN.  相似文献   
4.
5.
6.
泪管-耳-牙-指(趾)(LADD)综合征是一种具有多种表现的常染色体显性遗传疾病。最初在1967年由Levy报道。1例双侧泪液系统缺失、杯状耳、干嘴,以及牙、手臂和指(趾)异常的单发病例。之后一些新发现的临床表现,如肾脏异常、唾液腺缺乏、先天性髋脱位、先天性裂孔疝和横膈疝、感觉性耳聋和传导性耳聋、牙发育不全、四肢异常、口腔干燥和眼干都被报道与此综合征有关。  相似文献   
7.
8.
To evaluate whether the interleukin-6 (IL-6) -174 G/C polymorphism might alter the effects of micronized fenofibrate or simvastatin therapy on inflammatory markers, we measured IL-6, C-reactive protein, CD40 ligand, adhesion molecules, P-selectin and monocyte chemoattractant protein-1 in hypercholesterolemic patients both before and after a 30-day treatment. Serum IL-6 levels were significantly higher in patients with the GC or CC genotypes (P=0.04). The presence of the C allele was associated with greater absolute reduction of IL-6 levels (P=0.04) following fenofibrate treatment. There was no significant association between the -174 G/C IL-6 polymorphism and the effects of simvastatin treatment. A relationship between the -174 G/C IL-6 polymorphism and the anti-inflammatory action of fenofibrate reported might be useful in the optimization of the treatment regimen in patients receiving this class of drugs.  相似文献   
9.
To obtain a new model of chronic portal hypertension in the rat, two classical methods to produce portal hypertension, partial portal vein ligation and the oral administration of thioacetamide (TAA), have been combined. Male Wistar rats were divided into four groups: 1 (control; n?=?10), 2 [triple partial portal vein ligation (TPVL); n?=?9], 3 (TAA; n?=?11), and 4 (TPVL plus TAA; n?=?9). After 3 months, portal pressure, types of portosystemic collateral circulation, laboratory hepatic function tests (aspartate aminotransferase, alanine aminotransferase, bilirubin, alkaline phosphatase, and gamma-glutamyl transpeptidase) and liver histology were studied. The animals belonging to group 2 (TPVL) developed extrahepatic portosystemic collateral circulation, associated with mesenteric venous vasculopathy without hepatic destructurization or portal hypertension. Animals from group 3 (TAA) developed cirrhosis and portal hypertension but not extrahepatic portosystemic collateral circulation, or mesenteric venous vasculopathy. Finally, the animals from group 4 (TPVL?+?TAA) developed cirrhosis, portal hypertension, portosystemic collateral circulation, and mesenteric venous vasculopathy. The association of TPVL and TAA can be used to obtain a model of chronic portal hypertension in the rat that includes all the alterations that patients with hepatic cirrhosis usually have. This could, therefore, prove to be a useful tool to study the pathophysiological mechanisms involved in these alterations.  相似文献   
10.
Extracts from Erodium cicutarium L. Herit were tested for antiviral and interferon inducing properties. Both water extract and methanol extract as well as its fractions were observed to exert antiviral effect in relation to myxoviruses, Herpes virus type 1, Vesicular stomatitis and vaccinia virus. None of these extracts did induce interferon in a suspension of human leukocytes.  相似文献   
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