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   5290篇
  免费   184篇
  国内免费   38篇
耳鼻咽喉   154篇
儿科学   182篇
妇产科学   291篇
基础医学   311篇
口腔科学   323篇
临床医学   401篇
内科学   1263篇
皮肤病学   58篇
神经病学   369篇
特种医学   230篇
外科学   1143篇
综合类   67篇
预防医学   97篇
眼科学   222篇
药学   162篇
中国医学   3篇
肿瘤学   236篇
  2024年   2篇
  2023年   33篇
  2022年   53篇
  2021年   124篇
  2020年   78篇
  2019年   88篇
  2018年   107篇
  2017年   109篇
  2016年   179篇
  2015年   198篇
  2014年   233篇
  2013年   303篇
  2012年   408篇
  2011年   378篇
  2010年   236篇
  2009年   207篇
  2008年   374篇
  2007年   470篇
  2006年   420篇
  2005年   425篇
  2004年   382篇
  2003年   250篇
  2002年   279篇
  2001年   38篇
  2000年   11篇
  1999年   11篇
  1998年   16篇
  1997年   15篇
  1996年   14篇
  1995年   10篇
  1994年   10篇
  1993年   6篇
  1992年   6篇
  1991年   9篇
  1989年   4篇
  1988年   1篇
  1987年   6篇
  1985年   5篇
  1984年   3篇
  1983年   2篇
  1981年   1篇
  1980年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1973年   1篇
  1972年   1篇
  1971年   1篇
  1963年   1篇
排序方式: 共有5512条查询结果,搜索用时 15 毫秒
91.
ObjectiveAltered serum S100B protein levels have been shown in several psychiatric disorders. Our aim was to investigate whether plasma S100B is different in patients with panic disorder (PD) when compared with controls. Our second aim was to investigate whether treatment with SSRIs have an effect on S100B levels in patients with PD.MethodsThe sample included 32 patients diagnosed with PD (21 women, 11 men) per DSM-IV criteria and 21 healthy controls (11 women, 10 men). S100B levels were measured with BioVendor Human S100B ELISA (Enzyme Linked Immunosorbent Assay) kit.Results14 patients were not on drug treatment (43.8%) while 18 patients were taking various SSRIs. Median S100B value was 151.7 pg/mL (minimum-maximum: 120.4-164.7 pg/mL) in the control group, 147.4 pg/mL (minimum-maximum: 138.8-154.1 pg/mL) in the drug free group and 153.0 pg/mL (minimum-maximum: 137.9-164.7 pg/mL) in the treatment group. Kruskal-Wallis analysis showed a significant diffrerence among the three groups (z=9.9, df=2, p=0.007). Follow up Mann-Whitney-U tests indicated that while the control and the patients with treatment were not significantly different (z=-0.05, p=0.96), there were significant differences between the control group and untreated patients (z=-2.6, p=0.009) and treated and untreated patients (z=-3.0, p=0.003).ConclusionOur results suggested that, serum S100B protein level might be decreased in untreated PD patients and that patients who were treated with SSRIs had similar S100B level to healthy controls.  相似文献   
92.
Increased deposition of the extracellular matrix components, particularly collagen, is a central phenomenon in liver fibrosis. Stellate cells, the central mediators in the pathogenesis of fibrosis are activated by free radicals, and synthesize collagen. Melatonin is a potent physiological scavenger of hydroxyl radicals. Melatonin has also been shown to be involved in the inhibitory regulation of collagen content in tissues. At present, no effective treatment of liver fibrosis is available for clinical use. We aimed to test the effects of melatonin on dimethylnitrosamine (DMN)-induced liver damage in rats. Wistar albino rats were injected with DMN intraperitoneally. Following a single dose of 40 mg/kg DMN, either saline (DMN) or 100 mg/kg daily melatonin was administered for 14 days. In other rats, physiologic saline or melatonin were injected for 14 days, following a single injection of saline as control. Hepatic fibrotic changes were evaluated biochemically by measuring tissue hydroxyproline levels and histopathogical examination. Malondialdehyde (MDA), an end product of lipid peroxidation, and glutathione (GSH) and superoxide dismutase (SOD) levels were evaluated in blood and tissue homogenates. DMN caused hepatic fibrotic changes, whereas melatonin suppressed these changes in five of 14 rats (P < 0.05). DMN administration resulted in increased hydroxyproline and MDA levels, and decreased GSH and SOD levels, whereas melatonin reversed these effects. When melatonin was administered alone, no significant changes in biochemical parameters were noted. In conclusion, the present study suggests that melatonin functions as a potent fibrosuppressant and antioxidant, and may be a therapeutic choice.  相似文献   
93.
94.
Role of the coronary sinus in maintenance of atrial fibrillation   总被引:2,自引:0,他引:2  
INTRODUCTION: Bursts of tachycardia arising in the pulmonary veins may play an important role in perpetuating atrial fibrillation (AF). However, the role of the coronary sinus (CS) in the perpetuation of AF has been unclear. The aim of this study was to determine whether the CS plays a role in perpetuation of AF. METHODS AND RESULTS: Pulmonary vein isolation was performed by segmental ostial ablation with radiofrequency energy in 22 consecutive patients with paroxysmal AF. Bipolar and unipolar electrograms recorded in the left atrium and CS were analyzed during atrial pacing from the mitral annulus and during AF. There was a mean of 2.5 +/- 0.5 electrical connections between the CS and the left atrium. The electrical connections between the left atrium and CS were ablated with a mean of 6.2 +/- 2.7 minutes of radiofrequency energy applied along the atrial side of the inferior mitral annulus. During AF, episodes of intermittent tachycardia alternated between the left atrium and the CS. Among the 22 patients, sustained AF was still inducible in 9 after pulmonary vein isolation. After electrical disconnection of the CS from the left atrium, sustained AF was inducible in only 3 of these 9 patients. CONCLUSION: The CS may be a source of rapid repetitive electrical activity during AF. The lower probability of inducible sustained AF after electrical disconnection of the CS from the left atrium suggests that the CS may play a role in perpetuating AF.  相似文献   
95.
We present two patients who had high grade unilateral carotid artery stenosis and controlateral carotid artery occlusion secondary to active stage of Takayasu arteritis. The patients were presented with hemiplegia and history of transient ischemic attacks and visual disturbances. Despite the administration of high dose systemic corticosteroids, both patients deteriorated clinically and surgery was not preferred. Angiogram of the first patient revealed the occlusion of the right common carotid, right subclavian and left subclavian artery and high grade stenosis (>95%) of the left common carotid and right vertebral artery. These two stenotic arteries were stented. Angiogram of the second patient revealed the occlusion of the left common carotid and subclavian artery and high grade stenosis (>90%) of the right common carotid artery. PTA + stenting of the right carotid artery was performed. There were no complications during a follow-up period of 10.5±7 months and control angiograms revealed that all stented vessels were free of restenosis. In conclusion, stent-supported PTA to carotid arteries provides immediate symptomatic relief for patients in the active phase of the disease. Its efficacy in the long term should be investigated.  相似文献   
96.
97.
98.
New files (ProTaper Next/HyFlex/OneShape) are made from novel nickel‐titanium (NiTi) alloys/treatments. The purpose of this study was to compare the cyclic fatigue resistance of these new instruments with that of Revo‐S instruments. Four groups of 20 NiTi endodontic instruments were tested in steel canals with a 3 mm radius and a 60° angle of curvature. The cyclic fatigue of the following NiTi instruments with a tip size 25 and 0.06 taper that were manufactured with different alloys was tested: ProTaper Next X2 (M‐Wire), OneShape (conventional NiTi), Revo‐S Shaping Universal (conventional NiTi) and HyFlex 25/0.6 (controlled memory NiTi wire). A one‐way anova and post‐hoc Tukey's test (α = 0.05) revealed that the HyFlex files had the highest fatigue resistance and the Revo‐S had the least fatigue resistance among the groups (P < 0.001).  相似文献   
99.
100.
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