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   219492篇
  免费   17435篇
  国内免费   7105篇
耳鼻咽喉   1281篇
儿科学   7744篇
妇产科学   1582篇
基础医学   19867篇
口腔科学   3618篇
临床医学   23169篇
内科学   55858篇
皮肤病学   2809篇
神经病学   26192篇
特种医学   6277篇
外国民族医学   4篇
外科学   16648篇
综合类   30106篇
现状与发展   31篇
一般理论   9篇
预防医学   17423篇
眼科学   2369篇
药学   15189篇
  185篇
中国医学   9963篇
肿瘤学   3708篇
  2024年   404篇
  2023年   4386篇
  2022年   6068篇
  2021年   11792篇
  2020年   11032篇
  2019年   8420篇
  2018年   8367篇
  2017年   8262篇
  2016年   8613篇
  2015年   8283篇
  2014年   15771篇
  2013年   17280篇
  2012年   12857篇
  2011年   13911篇
  2010年   10934篇
  2009年   10541篇
  2008年   10538篇
  2007年   10184篇
  2006年   9083篇
  2005年   7497篇
  2004年   6362篇
  2003年   5471篇
  2002年   4605篇
  2001年   3973篇
  2000年   3331篇
  1999年   2837篇
  1998年   2723篇
  1997年   2407篇
  1996年   2150篇
  1995年   1945篇
  1994年   1787篇
  1993年   1562篇
  1992年   1461篇
  1991年   1289篇
  1990年   1021篇
  1989年   869篇
  1988年   812篇
  1987年   741篇
  1986年   638篇
  1985年   739篇
  1984年   624篇
  1983年   381篇
  1982年   450篇
  1981年   378篇
  1980年   283篇
  1979年   249篇
  1978年   186篇
  1977年   167篇
  1976年   138篇
  1974年   50篇
排序方式: 共有10000条查询结果,搜索用时 28 毫秒
991.
Wilson disease (WD) is a hereditary disorder, with recessive transmission and genetic heterogeneity. Several mutations of ATP7B, the gene underlying WD, were reported in many ethnic groups. In this study, mutation screening in ATP7B of 56 Saudi Arabian WD patients was undertaken. The clinical data of all patients were recorded. The entire ATP7B coding sequence, including intron-exon boundaries were screened for mutation by the polymerase chain reaction (PCR)-based mutation detection technique and DNA sequencing. Thirty-nine patients were symptomatic at presentation and 17 subjects were pre-symptomatic siblings of affected patients. Fourteen patients had neurological, 11 patients had mixed (hepatic and neurological), and 14 patients had hepatic presentations. Family history suggestive of WD was present in 72% of cases and 68% had consanguineous parents. Genetic analysis showed disease-causing mutations in three exons (exons 8, 19 and 21) of the ATP7B gene in 28 patients (50%). Mutations in exons 21 (18 cases) and 19 (one case) were unique for Saudis. This large series of Saudi patients with WD has shown wide variability in the genomic substrate of WD. There is no correlation between genotype and clinical presentation.  相似文献   
992.
Myositis is a rare complication following renal transplantation and is most commonly the result of drug-mediated myotoxicity. Other causative disorders include viral infection, electrolyte imbalance and myositis of autoimmune origin. We describe a 60-year-old patient who developed acute polymyositis 4 weeks after a 000 human leukocyte antigen (HLA) mismatch cadaveric renal transplant. Following an uncomplicated transplant course with maintenance triple immunosuppression (prednisolone, mycophenolate mofetil and cyclosporine), the patient presented with severe symmetrical proximal muscle weakness associated with a rise in serum creatine kinase to 46800 U/L. Electromyography confirmed myopathic changes and muscle biopsy demonstrated extensive muscle-fiber necrosis with an inflammatory infiltrate. There were no obviously culpable drugs and viral studies were negative. Prompt initiation of high-dose steroid therapy led to clinical and biochemical recovery. Acute polymyositis may occur following renal transplantation. Potential mechanisms include viral antigen transmission or a localized form of graft vs. host disease.  相似文献   
993.
目的 克隆人野生型parkin基因并构建真核表达载体pCDNA3.1—parkin,将重组质粒转染PC12细胞获得高表达人野生型parkin基因的PC12细胞克隆。方法 从胎脑组织中提取总RNA,用RT—PCR方法获得人野生型parkin基因的全长cDNA,插入pCR2.1—TA克隆载体中进行序列测定,测序正确后将其亚克隆至表达载体pCD—NA3.1,利用脂质体将重组质粒转染PC12细胞,经G418筛选获得抗性细胞克隆,采用RT—PCR和Western Blot方法鉴定人野生型parkin基因在PC12细胞中的过表达。结果 经限制性内切酶酶切图谱分析和DNA序列测定证实目的基因已插入重组质粒,RT—PCR和Western Blot证明经G418筛选得到的转基因PC12细胞克隆中存在人野生型parkin基因的表达。结论 成功构建了人野生型parkin基因的真核表达载体,获得了稳定表达人野生型parkin基因的PC12细胞克隆,为进一步研究parkin的生物学功能以及parkin在帕金森病发病机制中的作用奠定了良好的基础。  相似文献   
994.
目的 研究急性泛植物神经神经病的临床表现、诊断和治疗。方法 总结 2例患者病史、植物神经受损表现、神经电生理学及脑脊液等实验室检查特点和治疗 ,并结合文献进行分析。结果  2例患者均急性起病 ,有明显的体位性低血压、固定心率及其他广泛的植物神经功能损害症状。结论 了解急性泛植物神经神经病的临床特点有助于正确诊断与治疗。  相似文献   
995.
肾上腺脑白质营养不良MRI表现(附3例报告及文献复习)   总被引:1,自引:0,他引:1  
目的 探讨肾上腺脑白质营养不良的MRI特征,提高对本病的认识。方法 回顾性分析3例经临床和生化证实的。肾上腺脑白质营养不良患者的MRI表现。结果 3例患者均表现为双侧对称性侧脑室三角区白质病变,T1WI呈低信号,T2WI呈高信号,经胼胝体压部相连,呈蝶翼状分布。结论肾上腺脑白质营养不良的MRI表现具有典型特征,MR检查能准确反映病变的病理变化、范围及进展情况。MRI作为一种无创性并且敏感的检查方法,在对肾上腺脑白质营养不良的诊断和治疗方面具有重要的指导意义。  相似文献   
996.
Richard H. Myers 《NeuroRx》2004,1(2):255-262
Summary:Huntington’s disease (HD) is a dominantly transmitted neurodegenerative disorder with wide variation in onset age but with an average age at onset of 40 years. Children of HD gene carriers have a 50% chance of inheriting the disease. The characteristic symptoms of HD are involuntary choreiform movements, cognitive impairment, mood disorders, and behavioral changes which are chronic and progressive over the course of the illness. HD is a “trinucleotide repeat” disorder, which is caused by an increase in the number of CAG repeats in the HD gene. Repeats of 40 or larger are associated with disease expression, whereas repeats of 26 and smaller are normal. Intermediate numbers of repeats, between 27 and 35, are not associated with disease expression but may expand in paternal transmission, resulting in the disease in descendents. Repeats of 36–39 are associated with reduced penetrance whereby some develop HD and others do not. The identification of the genetic defect in HD permits direct genetic testing for the presence of the gene alteration responsible for the disease. Tests may be performed in three circumstances: (1) confirmation of diagnosis, (2) predictive testing of persons at genetic risk for inheriting HD, and (3) prenatal testing. Testing is widely available and much experience has been gained with protocols that assist the individual in making an informed choice about test options, and minimize the occurrence of adverse emotional outcomes.  相似文献   
997.
OBJECTIVE: To examine the effect of short-term improvements in glycaemic control on brachial artery endothelial function as a marker of cardiovascular health. METHODS: Persons with Type 2 diabetes who were poorly controlled on oral therapy were randomly assigned to monotherapy with repaglinide or combination therapy with repaglinide plus metformin. Brachial artery flow-mediated vasodilation was assessed by ultrasonography at randomization and following 16 weeks of therapy. The primary outcome was change in brachial artery endothelial function from baseline. Comparison of randomized groups was a secondary aim. RESULTS: Eighty-six participants were randomized, and 83 were followed to study completion. Post occlusion brachial artery vasodilation was 3.74% at baseline and 3.82% following 16 weeks of therapy (P = 0.77). The treatment effect was 0.08% (95% CI: -0.48%, 0.64%). No difference was seen between treatment groups (P = 0.69). Overall, A1C was reduced from 8.3% to 7.0%, with a greater reduction in the combination therapy group (from 8.4% to 6.7%) than in the monotherapy group (from 8.3% to 7.3%, p for difference between groups = 0.01). Statistically significant reductions were observed in fasting glucose, and plasminogen activator inhibitor-1. Statistically significant increases were observed for fasting insulin, uric acid, weight and BMI. CONCLUSIONS: Brachial artery endothelial function was not influenced by short-term improvements in glycaemic control. The CONTROL DM group was successful in lowering A1C. Future research should explore more intensive and longer-lasting improvements in glycaemic control on endothelial function. Some data previously published in abstract form (Diabetes 2001; 50 (Suppl. 2): A217).  相似文献   
998.
目的:评价盐酸帕罗西汀治疗躯体疾病伴发焦虑的疗效。方法:对我院2002年1月-2003年.3月内外科躯体疾患伴发焦虑患者进行开放性平行对照研究,对照组用多虑平治疗,为期六周,采用HAMA、CGI量表评定临床效果,以TESS评定不良反应。结果:共65例(帕罗西汀31例,多虑平组34例),临床判断帕罗西汀与多虑平的显效率分别为66.7%和69.4%,无显著差异,治疗后一周,多虑平组HAMA减分率优于帕罗西汀组,治疗二周后无显著差异。副反应的发生率,帕罗西汀组为17.6%,远低于多虑平组的34.6%。结论:帕罗西汀是一种疗效好,安全性高的治疗躯体疾病伴发焦虑的首选药物。  相似文献   
999.
Background: Gastrointestinal strictures are the most often and serious complication in Crohn's disease. Because of the frequent postoperative recurrence in Crohn's disease, endoscopic therapy of gastrointestinal stricture is one of the best therapeutic options. Method: The present study sets out the results from a prospective study of endoscopic dilation therapy on 48 Crohn's disease patients with severe gastrointestinal stenoses. All patients who could not undergo endoscopic balloon dilation therapy (EBD) were operated on. Results: Long‐term success was attained in 32 of the 48 patients; cumulative avoidance of surgery after EBD was 86% at one year and 71% at three. Second, the most hazardous factor was recurrent inflammation causing restenosis. Patients who had strictures with oral luminal dilatation and patients with frequent recurrence had a tendency to be operated on. As a complication, perforation occurred in two cases (3.3%). Conclusions: EBD therapy for Crohn's stricture in the gastrointestinal tract is recommended before surgical intervention.  相似文献   
1000.
目的应用间期荧光原位杂交技术(I-FISH)检测初诊急性白血病患者中核心结合因子(CBF)受累的染色体异常情况并对治疗后患者的微小残留病(MRD)进行监测,同时对I-FISH与常规染色体G显带的灵敏度进行比较。方法在骨髓形态学初筛的基础上,应用常规染色体G显带技术对15例急性髓系白血病(AML)进行核型分析,应用I-FISH对患者可能受累的CBF相关靶基因进行检测,其中7例患者治疗后进行了MRD监测。结果(1)正常对照组中,CYTOCELL公司提供的3种探针(AML1/ETO易位探针、MYH11基因断裂点双色探针和ETV6/AML1易位探针)的正常分界值分别为4.13%、1.95%和2.12%。(2)常规染色体G显带分析,15例患者中有6例伴有潜在累及CBF基因的染色体异常,其中8例AML-M2中5例伴t(8;21),2例AML-M4EO中1例伴inv(16),5例儿童B系急性淋巴细胞白血病(B-ALL)未检出相应的异常。I-FISH检测15例患者发现有12例累及CBF基因,其中8例AML-M2患者均为AML1/ETO融合基因(+),2例AML-M4EO病人CBFβ/MYH11融合基因均为(+),5例儿童B-ALL中2例ETV6/AML融合基因(+)。(3)3例AML-M2患者中2例MRD阳性;2例M4E0患者治疗后MRD监测结果均阴性;2例B-ALL患者1例阴性,1例阳性。结论I-FISH较常规染色体G显带技术能够更灵敏地检测出累及CBF的急性白血病,在初诊时联合应用这两种  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