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   2447篇
  免费   228篇
  国内免费   8篇
耳鼻咽喉   33篇
儿科学   81篇
妇产科学   58篇
基础医学   367篇
口腔科学   83篇
临床医学   184篇
内科学   588篇
皮肤病学   68篇
神经病学   233篇
特种医学   61篇
外科学   430篇
综合类   12篇
一般理论   3篇
预防医学   169篇
眼科学   49篇
药学   156篇
中国医学   23篇
肿瘤学   85篇
  2023年   24篇
  2021年   71篇
  2020年   38篇
  2019年   73篇
  2018年   69篇
  2017年   69篇
  2016年   56篇
  2015年   59篇
  2014年   76篇
  2013年   82篇
  2012年   147篇
  2011年   156篇
  2010年   98篇
  2009年   77篇
  2008年   131篇
  2007年   149篇
  2006年   151篇
  2005年   123篇
  2004年   95篇
  2003年   107篇
  2002年   113篇
  2001年   77篇
  2000年   99篇
  1999年   62篇
  1998年   18篇
  1997年   13篇
  1996年   15篇
  1995年   20篇
  1994年   8篇
  1992年   41篇
  1991年   43篇
  1990年   30篇
  1989年   24篇
  1988年   20篇
  1987年   24篇
  1986年   21篇
  1985年   11篇
  1984年   11篇
  1981年   10篇
  1979年   18篇
  1978年   9篇
  1976年   9篇
  1975年   8篇
  1973年   7篇
  1972年   12篇
  1970年   14篇
  1969年   13篇
  1968年   14篇
  1967年   7篇
  1966年   9篇
排序方式: 共有2683条查询结果,搜索用时 257 毫秒
1.
Breast pseudoaneurysms after a core needle biopsy are a rare complication with a low incidence. However, it is important to be aware of the possibility of complications that require treatment.  相似文献   
2.
3.
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   
4.
Between 4/1986 to 1/1989, 74 orthotopic liver transplantation were performed in 62 patients (62 first liver transplants, 10 as second graft and two as a third graft); 57 in adults and 17 in children. The main indication for the operation was liver cirrhosis (61.4%) (the most frequent etiology was alcoholic cirrhosis, 28.5%). Six cirrhotic patients had a hepatocarcinoma (9.6%). Two received a liver and kidney transplant due to terminal renal insufficiency and hemodialysis. The most frequent indication in children was biliary atresia (33.3%). Six patients had a fulminal liver failure (9.6%). AB0 blood group compatibility was identical in 87.5%, compatible in six and incompatible in three patients. Total orthotopic liver transplantation was performed in 67 patients, and size-reduced liver was indicated in 7 patients. Extracorporeal veno-venous bypass was used in adults but never in children. In 93.1% of the transplants a single hepatic artery was anastomosed to the recipient and in 6.9% a double anastomosis was performed. In 62.5% of the patients a end-to-end choledocho-choledochostomy was performed and in 34.8% hepatico-jejunostomy was indicated. Three months postoperative mortality rate was 12.9%. Arterial stenosis and thrombosis were the most frequent complication.  相似文献   
5.
Percutaneous embolization of large portosystemic collaterals was performed in three patients following placement of a transjugular intrahepatic portosystemic shunt in order to improve hepatopetal portal flow. Improved hepatic portal perfusion was achieved in these cases, thereby theoretically reducing the risk of chronic hepatic encephalopathy.  相似文献   
6.
7.
8.
9.
10.
The ability of nicotine to induce a cytoprotective or neuroprotective action occurs through several down-stream mechanisms. One possibility is that the drug increases the expression of tyrosine kinase A (TrkA) nerve growth factor (NGF) receptors. Certain β-amyloid peptides (e.g., Aβ1–42) have been shown to bind with high affinity to α7 nicotinic receptors and thus interfere with a potentially neurotrophic influence. Treatment of differentiated PC-12 cells with nicotine produced a concentration-dependent increase in cell-surface TrkA receptors that occurred concomitantly with cytoprotection. The effect of nicotine was blocked by either of the α7 receptor antagonists α-bungarotoxin (α-BTX) or methyllycaconatine. The cytoprotective action of nicotine also was inhibited by pretreatment with 10–100 nM Aβ1–42. Nicotine also was administered (four injections of 30 μg, spaced evenly over 24 h) to rats by direct injection into a lateral cerebral ventricle. Brain TrkA expression was increased significantly in hippocampus and entorhinal cortex (up to 32% above control), with no changes found in cerebral cortex or hypothalamus. The nicotine-induced increases in TrKA expression in hippocampus and entorhinal cortex were significantly inhibited by 10 μg α-BTX or by 10 nmol Aβ1–42. Therefore, physiologically relevant concentrations of Aβ1–42 can prevent nicotine-induced TrkA receptor expression in brain regions containing cholinergic neurons susceptible to the neurotoxicity associated with Alzheimer’s disease.  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