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   17725篇
  免费   1704篇
  国内免费   1280篇
耳鼻咽喉   93篇
儿科学   164篇
妇产科学   174篇
基础医学   1854篇
口腔科学   313篇
临床医学   2024篇
内科学   2439篇
皮肤病学   262篇
神经病学   780篇
特种医学   687篇
外国民族医学   1篇
外科学   2100篇
综合类   3789篇
现状与发展   4篇
一般理论   1篇
预防医学   1414篇
眼科学   369篇
药学   2000篇
  17篇
中国医学   992篇
肿瘤学   1232篇
  2024年   35篇
  2023年   171篇
  2022年   428篇
  2021年   639篇
  2020年   584篇
  2019年   465篇
  2018年   552篇
  2017年   526篇
  2016年   506篇
  2015年   732篇
  2014年   923篇
  2013年   905篇
  2012年   1316篇
  2011年   1369篇
  2010年   990篇
  2009年   953篇
  2008年   1034篇
  2007年   1104篇
  2006年   1010篇
  2005年   869篇
  2004年   968篇
  2003年   1062篇
  2002年   913篇
  2001年   669篇
  2000年   484篇
  1999年   303篇
  1998年   186篇
  1997年   177篇
  1996年   123篇
  1995年   103篇
  1994年   89篇
  1993年   69篇
  1992年   70篇
  1991年   60篇
  1990年   54篇
  1989年   40篇
  1988年   38篇
  1987年   27篇
  1986年   31篇
  1985年   15篇
  1984年   16篇
  1983年   14篇
  1982年   13篇
  1981年   9篇
  1979年   13篇
  1972年   5篇
  1971年   4篇
  1970年   8篇
  1969年   10篇
  1968年   4篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
1.
2.
INTRODUCTIONPsoriasis is a chronic inflammatory condition that affects the skin and joints, and is associated with cardiovascular risk factors, including metabolic syndrome (MetS). We aimed to assess the prevalence of MetS in patients with psoriasis and determine whether there was a correlation between psoriasis severity and MetS in a Singapore population.METHODSThis was a cross-sectional study of patients with psoriasis, aged 18–69 years, who attended a tertiary dermatology referral centre in Singapore from October 2007 to February 2009. Fasting glucose, lipids, blood pressure, Psoriasis Area and Severity Index, and body mass index were measured. MetS was diagnosed in the presence of three or more criteria of the modified National Cholesterol Education Program Adult Treatment Panel III.RESULTSAmong 338 patients with psoriasis, there were 238 (70.4%) men and 100 (29.6%) women, who were Chinese (n = 228; 67.5%), Malay (n = 52; 15.4%) and Indian (n = 58; 17.2%). The prevalence of MetS was 45.1%. MetS was 44% more prevalent in patients older than 50 years (p = 0.02). Malay patients with psoriasis were significantly more likely to have hypertriglyceridaemia, elevated fasting plasma glucose and abdominal obesity. There was no significant correlation between psoriasis severity and risk of MetS.CONCLUSIONThe prevalence of MetS in patients with psoriasis in Singapore was 45.1%, or nearly threefold higher than the Singapore general population. Patients with psoriasis should be screened yearly for MetS and any modifiable cardiovascular risk factors should be actively controlled.  相似文献   
3.
陈海  杨黎  王晓华 《医学综述》2016,(4):778-781
目的研究葛根素联合复方樟柳碱注射液对眼底病患者的治疗效果及对血液流变学指标的影响。方法选择2013年4月至2014年4月在绵阳市第三人民医院眼科进行眼底病治疗的患者100例,并按入院顺序抽签随机分为观察组和对照组,各50例。对照组进行葛根素常规治疗(葛根素注射液0.4 g加入生理盐水250 m L中静脉滴注,每日1次,1个疗程14 d,1个疗程后停药3 d,再进行下一疗程),观察组在此基础上联合复方樟柳碱注射液进行治疗(采用复方樟柳碱2 m L在患者颞浅动脉旁行皮下注射,每日1次,1个疗程14 d,完成1个疗程后停药3 d,再换肾俞穴进行注射,1个疗程后停药3 d,再进行第一个疗程的用药)。3个疗程后,比较两组患者治疗前后血液流变学的变化、术后复发率和不良反应情况及患者的治疗效果。结果治疗后,观察组全血黏度为(4.82±0.41)m Pa·s明显低于对照组的(5.56±0.39)m Pa·s,红细胞聚集指数(3.80±0.41)明显低于对照组(4.77±0.55),纤维蛋白原(4.20±0.24)g/L明显低于对照组(5.25±0.43)g/L,差异均有统计学意义(t=9.247,9.998,15.077,P<0.01);观察组患者治疗后复发率为2.0%(1/50),不良反应的总发生率为4.0%(2/50),分别低于对照组14.0%(7/50)和18.0%(9/50)(P<0.01);观察组患者的总有效率为98.0%(49/50),显著高于对照组的82.0%(41/50)(P<0.05)。结论葛根素和复方樟柳碱注射液联合治疗眼底病患者,可改善患者血液流变学,并提高临床治疗效果。  相似文献   
4.
5.
6.
目的 解析真实世界中乳腺恶性肿瘤患者的人群特征、诊断特征、中西医用药特征,为乳腺癌的临床防治提供参考。方法 采集2002年2月至2015年5月全国60家三级甲等医 院信息系统(Hospital Information System,HIS)中,出院诊断为“乳腺癌”的患者用药信息,采用SAS9.3统计软件,对人口学信息、诊断信息、医嘱用药信息等进行描述性分析。结果 39798例乳腺癌患者,平均年龄(50.93者,平均年龄)岁;多以门诊入院,入院病情以“一般”为主;合并疾病主要为高血压,骨肿瘤,联用西药以抑制肿瘤细胞增殖、治疗并发症、缓解放化疗不良反应为主;中医辨证以痰瘀互结证,气阴两虚证,肝气淤滞证,脾气亏虚证型最为常见,临床清热解毒剂、益气扶正剂,活血化瘀剂应用较多。结论 乳腺癌中西医结合治疗,联用药物广泛,临床治疗基本符合临床指南。  相似文献   
7.
线粒体脑肌病属于罕见性母系遗传病,本文回顾性分析了1家4例高乳酸血症-卒中样发作综合征(MELAS)型线粒体脑肌病患者,其主要表现为卒中样发作、头痛、癫痫、高乳酸血症、肌肉不耐受疲劳、高级智能下降、听力下降和身材矮小等,结合特征性影像学变化、基因检测及肌肉活检明确诊断,并结合文献对只有女儿能将其线粒体DNA(mt-DNA)传递给下一代的母系遗传MELAS型线粒体脑肌病临床特点进行了总结分析,旨在帮助临床认识此病,进一步提高MELAS型线粒体脑肌病的临床诊断率。  相似文献   
8.
Myostatin (MSTN) is a transforming growth factor-β (TGF-β) family member that normally acts to limit muscle growth. The function of MSTN is partially redundant with that of another TGF-β family member, activin A. MSTN and activin A are capable of signaling through a complex of type II and type I receptors. Here, we investigated the roles of two type II receptors (ACVR2 and ACVR2B) and two type I receptors (ALK4 and ALK5) in the regulation of muscle mass by these ligands by genetically targeting these receptors either alone or in combination specifically in myofibers in mice. We show that targeting signaling in myofibers is sufficient to cause significant increases in muscle mass, showing that myofibers are the direct target for signaling by these ligands in the regulation of muscle growth. Moreover, we show that there is functional redundancy between the two type II receptors as well as between the two type I receptors and that all four type II/type I receptor combinations are utilized in vivo. Targeting signaling specifically in myofibers also led to reductions in overall body fat content and improved glucose metabolism in mice fed either regular chow or a high-fat diet, demonstrating that these metabolic effects are the result of enhanced muscling. We observed no effect, however, on either bone density or muscle regeneration in mice in which signaling was targeted in myofibers. The latter finding implies that MSTN likely signals to other cells, such as satellite cells, in addition to myofibers to regulate muscle homeostasis.

Myostatin (MSTN) is a secreted signaling molecule that normally acts to limit skeletal muscle growth (for review, see ref. 1). Mice lacking MSTN exhibit dramatic increases in muscle mass throughout the body, with individual muscles growing to about twice the normal size (2). MSTN appears to play two distinct roles in regulating muscle size, one to regulate the number of muscle fibers that are formed during development and a second to regulate the growth of those fibers postnatally. The sequence of MSTN has been highly conserved through evolution, with the mature MSTN peptide being identical in species as divergent as humans and turkeys (3). The function of MSTN has also been conserved, and targeted or naturally occurring mutations in MSTN have been shown to cause increased muscling in numerous species, including cattle (35), sheep (6), dogs (7), rabbits (8), rats (9), swine (10), goats (11), and humans (12). Numerous pharmaceutical and biotechnology companies have developed biologic agents capable of blocking MSTN activity, and these have been tested in clinical trials for a wide range of indications, including Duchenne and facioscapulohumeral muscular dystrophy, inclusion body myositis, muscle atrophy following falls and hip fracture surgery, age-related sarcopenia, Charcot–Marie–Tooth disease, and cachexia due to chronic obstructive pulmonary disease, end-stage kidney disease, and cancer.The finding that certain inhibitors of MSTN signaling can increase muscle mass even in Mstn−/− mice revealed that the function of MSTN as a negative regulator of muscle mass is partially redundant with at least one other TGF-β family member (13, 14), and subsequent studies have identified activin A as one of these cooperating ligands (15, 16). MSTN and activin A share many key regulatory and signaling components. For example, the activities of both MSTN and activin A can be modulated extracellularly by naturally occurring inhibitory binding proteins, including follistatin (17, 18) and the follistatin-related protein, FSTL-3 or FLRG (19, 20). Moreover, MSTN and activin A also appear to share receptor components. Based on in vitro studies, MSTN is capable of binding initially to the activin type II receptors, ACVR2 and ACVR2B (also called ActRIIA and ActRIIB) (18) followed by engagement of the type I receptors, ALK4 and ALK5 (21). In previous studies, we presented genetic evidence supporting a role for both ACVR2 and ACVR2B in mediating MSTN signaling and regulating muscle mass in vivo. Specifically, we showed that mice expressing a truncated, dominant-negative form of ACVR2B in skeletal muscle (18) or carrying deletion mutations in Acvr2 and/or Acvr2b (13) have significantly increased muscle mass. One limitation of the latter study, however, was that we could not examine the consequence of complete loss of both receptors using the deletion alleles, as double homozygous mutants die early during embryogenesis (22). Moreover, the roles that the two type I receptors, ALK4 and ALK5, play in regulating MSTN and activin A signaling in muscle in vivo have not yet been documented using genetic approaches. Here, we present the results of studies in which we used floxed alleles for each of the type II and type I receptor genes in order to target these receptors alone and in combination in muscle fibers. We show that these receptors are functionally redundant and that signaling through each of these receptors contributes to the overall control of muscle mass.  相似文献   
9.
目的探讨胼胝体梗死的临床表现、病因及鉴别诊断特点。方法对2005年7月收治的1例53岁男性胼胝体梗死患者的临床表现、影像学特点、病因机制及其治疗过程进行回顾分析。结果临床主要表现为发作性黑蒙、言语不利,既往有高血压、糖尿病、脑梗死、吸烟、饮酒史,体格检查以失用为主要表现。头部MRI检查可见左侧脑室旁、胼胝体梗死,右侧基底节、脑桥陈旧性腔隙性梗死;脑血管造影检查显示为多发性血管狭窄,其中以左侧大脑中动脉、右侧颈内动脉及基底动脉最为严重。经颈内动脉内膜剥离术及颈内动脉支架植入术治疗,临床症状缓解。结论失用可以是胼胝体梗死的主要表现,其病因是在脑动脉粥样硬化基础上的血流动力学改变,患者预后良好。  相似文献   
10.
64层CT下肢动脉成像技术研究   总被引:6,自引:0,他引:6  
目的探讨64层CT下肢动脉成像强化质量的对比剂注射方式。方法前瞻性地选择60例疑诊下肢动脉病变的病人,利用64层螺旋CT行下肢动脉CT血管成像。采用不同的扫描和重建参数,应用370mgI/100ml浓度的对比剂100ml团注或采用先70ml的对比剂后50ml的0.9%生理盐水用双筒高压注射器分别以4.0ml/s的注射速度团注入肘静脉,应用对比剂追踪触发扫描方式待腹主动脉CT阈值达120HU时延迟7s开始扫描;利用MIP和VR方式重建CTA图像;对比不同参数和不同对比剂应用方式的CT血管成像图像质量。结果最佳的扫描与重建参数为准直64×0.6mm,螺距1.5,层厚1.0,重建间隔50%;最佳的对比剂应用方式为(浓度为370mgI/100ml)对比剂70ml、生理盐水50ml以4.0ml/s注射速度按先后顺序团注。结论选择合适的准直、螺距以保证适当的扫描速度,选择合适的对比剂浓度、用量和注射速度以保证血管内足够的对比剂峰值浓度及峰值持续时间,此二者是64层CT下肢动脉成像成功的关键。  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