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   15129篇
  免费   1026篇
  国内免费   279篇
耳鼻咽喉   176篇
儿科学   287篇
妇产科学   592篇
基础医学   1781篇
口腔科学   740篇
临床医学   1422篇
内科学   2869篇
皮肤病学   160篇
神经病学   1501篇
特种医学   515篇
外科学   1996篇
综合类   987篇
一般理论   1篇
预防医学   985篇
眼科学   426篇
药学   1013篇
  4篇
中国医学   199篇
肿瘤学   780篇
  2023年   114篇
  2022年   204篇
  2021年   329篇
  2020年   232篇
  2019年   254篇
  2018年   300篇
  2017年   298篇
  2016年   295篇
  2015年   411篇
  2014年   416篇
  2013年   586篇
  2012年   715篇
  2011年   881篇
  2010年   655篇
  2009年   590篇
  2008年   750篇
  2007年   799篇
  2006年   729篇
  2005年   649篇
  2004年   624篇
  2003年   603篇
  2002年   582篇
  2001年   484篇
  2000年   452篇
  1999年   395篇
  1998年   195篇
  1997年   167篇
  1996年   135篇
  1995年   117篇
  1994年   138篇
  1993年   114篇
  1992年   236篇
  1991年   232篇
  1990年   201篇
  1989年   197篇
  1988年   194篇
  1987年   159篇
  1986年   163篇
  1985年   159篇
  1984年   109篇
  1983年   113篇
  1982年   71篇
  1980年   60篇
  1979年   87篇
  1978年   78篇
  1977年   69篇
  1975年   95篇
  1974年   71篇
  1973年   64篇
  1972年   68篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
目的观察急性冠状动脉综合征患者介入治疗后血小板活化指标CD62p、CD63及糖蛋白Ⅱb/Ⅲa受体复合物及内皮功能的改变。方法60例急性冠状动脉综合征患者在冠状动脉介入术前和术后即刻以及次日采用流式细胞仪检测血小板活化指标CD62p、CD63及糖蛋白Ⅱb/Ⅲa受体复合物;双抗体夹心固相酶联免疫吸附试验测定血浆假血友病因子的表达水平;放射免疫测定法测定血浆内皮素1表达水平;酶法测定血浆一氧化氮的含量;彩色多谱勒超声诊断仪测量内皮依赖性血管舒张功能。选择健康体检者和稳定型心绞痛患者各30例作对照,观察急性冠状动脉综合征患者冠状动脉介入前后指标的变化并与对照组比较。结果与健康对照组和稳定型心绞痛组比,急性冠状动脉综合征组CD62p、CD63及糖蛋白Ⅱb/Ⅲa受体复合物明显增高(P<0.05或0.01);急性冠状动脉综合征患者介入术后即刻CD62p、CD63和糖蛋白Ⅱb/Ⅲa受体复合物与术前相比明显增高(P<0.01),但术后24h较术前无明显变化(P>0.05)。与健康对照组和稳定型心绞痛组比,急性冠状动脉综合征组假血友病因子、内皮素1的表达水平明显增高(P<0.01),内皮依赖性血管舒张功能和一氧化氮降低(P<0.05或<0.01);急性冠状动脉综合征患者介入术后即刻血浆假血友病因子和内皮素1水平升高(P<0.05或P<0.01),内皮依赖性血管舒张功能和一氧化氮水平降低(P<0.05),且介入术后24h假血友病因子水平也较术前升高(P<0.05),内皮依赖性血管舒张功能降低(P<0.05),但内皮素1和一氧化氮水平与术前差异无显著性(P>0.05)。结论血小板活化和内皮功能的损伤在急性冠状动脉综合征发生和发展过程中起重要的作用,冠状动脉介入术后血管内皮受到一定损伤,血小板有一定程度的激活。  相似文献   
12.
OBJECTIVES: To present a single centers' 7-year experience in the endovascular treatment of acute traumatic lesions of the descending thoracic aorta (ATL of the DTA). MATERIALS & METHODS: Between March 1999 and December 2006, 34 consecutive acute traumatic lesions of the descending aorta (23 men, mean age 44 years) were treated endovascularly. Stentgrafts used were TAG Excluder, Zenith TX2 and Talent. In 23 patients the Left Subclavian Artery (LSA) was covered. Mean procedural duration was 20 to 75 minutes. RESULTS: Exclusion of the rupture site was achieved in all cases with no conversion to open surgery. Overall 30-day mortality was 8.8%. Two patients died on post operative day (pod) 1 and one on pod 22 from cranial injuries. No death or neurological deficit related to the endovascular treatment was reported. Four type I endoleaks required treatment either by balloon reexpansion (n=2) or by additional stentgraft implantation (n=2). In two patients the stentgraft collapsed totally several days postoperatively. Two patients required secondary surgical procedures (iliac access complication and revascularisation of the left subclavian artery n=1). The average follow-up was 43.8 months (1-93 months). No stentgraft related abnormality has been subsequently documented. CONCLUSIONS: The endovascular treatment of ATL of the DTA may offer the best means of therapy in a polytrauma patient.  相似文献   
13.
14.
15.
OBJECTIVES: The aim of this study was to investigate if radiation therapy (RT) favorably modulates wound healing at vein graft anastomoses. MATERIALS AND METHODS: Jugular vein grafts were sewn into carotid arteries in 32 rats which were randomly divided into two groups: RT (gamma source, 14 Gray, n=16) and control (C, sham irradiation, n=16). Grafts and adjacent arteries were analyzed at 2 (n=8) and 8 weeks (n=8) by histology, immunohistochemistry, and morphometry. RESULTS: Although, RT did not reduce the overall occurrence of intimal hyperplasia, the distribution differed. RT led to a reduction of intimal hyperplasia in arterial segments (median: C: 41.873 microm2; RT: 6.452 microm2, p < 0.0007). In contrast, RT augmented intimal hyperplasia in vein grafts (median: C: 30.287 microm2; RT: 90.455 microm2, p < 0.014). Vein graft diameters after RT were enlarged (median: C: 2.098 microm; RT: 3.381, p < 0.031). Over 80% of the cells were of mesenchymal origin in both groups. CONCLUSIONS: RT reduced intimal hyperplasia in arterial segments. However, RT led to graft dilatation and increased intimal hyperplasia in vein grafts. RT did not favorably modulate the vascular wound healing response in this model.  相似文献   
16.
Irritability is often a problem for patients with Post-Traumatic Stress Disorder (PTSD). We describe two cases that illustrate the use of lithium in the treatment of veterans with PTSD who complained of serious problems with irritability or angry outbursts. These cases are discussed in the context of evidence that lithium may be useful in other patients with disorders of impulse control. The evidence linking disorders of anger and impulse control to a dysregulation in neurotransmitter regulation, particularly in serotonergic pathways, supports a psychopharmacologic approach to treatment. These findings should lead to further study of the role of lithium in the treatment of this symptom complex in patients with PTSD.  相似文献   
17.
The renal and hemodynamic effects of dopamine were measured during the immediate postoperative period in six infants following repair of congenital cardiac defects. Dopamine was infused at rates of 5, 10, and 15 micrograms/kg/min. Cardiac index (CI) increased significantly at a dopamine infusion rate of 15 micrograms/kg/min. The glomerular filtration rate (GFR) and urine output increased at dopamine infusion rates of 5 and 10 micrograms/kg/min and returned to baseline at 15 micrograms/kg/min. No significant changes occurred in right atrial pressure (RAP), left atrial pressure (LAP), systemic artery pressure, systemic vascular resistance (SVR), or pulmonary vascular resistance (PVR). Heart rate (HR) increased slightly at a dopamine infusion rate of 15 micrograms/kg/min. Pulmonary artery pressure (PAP) increased significantly in only one patient. These data demonstrate that infants require high doses of dopamine to produce the hemodynamic effects seen in adults and that these higher doses may be used without adverse renal effects.  相似文献   
18.
19.
BACKGROUND: Dyslipidaemia, inflammation and oxidative stress are prominent risk factors that potentially cause vascular disease in haemodialysis patients. Dialysis modalities affect uraemic dyslipidaemia, possibly by modifying oxidative stress, but the effects of dialyser flux and membrane material on atherogenic remnant particles and oxidized low-density lipoproteins (LDL) are unknown. METHODS: We performed a randomized crossover study in 36 patients on haemodialysis to analyse the effect of dialyser flux and membrane material on plasma lipids, apolipoproteins and markers of inflammation and oxidative stress. Stable patients on low-flux dialysis with polysulphone for >/=6 weeks were assigned to high-flux polysulphone or high-flux modified cellulose with similar dialyser surface area and permeability characteristics and crossed over twice every 6 weeks. RESULTS: Thirty patients completed the study per protocol. Treatments with high-flux polysulphone and modified cellulose lowered serum triglyceride (by 20% and 10%, respectively; P<0.05) and remnant-like particle cholesterol by 32% (P<0.001) and 11% (NS) after the first 6 weeks of treatment. Oxidized LDL decreased significantly with high-flux polysulphone, but not with modified cellulose. Apolipoproteins CII and CIII were reduced, whereas the ratio CII/CIII was increased (all P<0.05). Acute-phase proteins and LDL and high-density lipoprotein cholesterol remained unaffected. CONCLUSIONS: This randomized crossover study demonstrates a potent effect of high-flux haemodialysis on uraemic dyslipidaemia. Polysulphone membrane material showed superiority on oxidatively modified LDL, an indicator of oxidative stress in haemodialysis patients.  相似文献   
20.
Cardiac insufficiency, coronary heart disease, and arrhythmia are not only more frequent in elderly patients, they are very often combined. By reason of cardiac morbidity and general morbidity as well as changed physiological and pathophysiological conditions, diagnosis of cardiac disease in elderly patients is more difficult. These conditions also apply to modifications in the therapy of cardiac diseases in advanced age. Especially pharmacodynamic and pharmacokinetic effects in advanced age combined with multimorbidity also account for the risk of interactions because of the simultaneous application of different pharmacological groups.  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