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   3401篇
  免费   124篇
  国内免费   32篇
耳鼻咽喉   7篇
儿科学   161篇
妇产科学   12篇
基础医学   140篇
口腔科学   4篇
临床医学   723篇
内科学   1094篇
皮肤病学   5篇
神经病学   169篇
特种医学   178篇
外科学   443篇
综合类   373篇
预防医学   73篇
眼科学   3篇
药学   106篇
  1篇
中国医学   14篇
肿瘤学   51篇
  2024年   3篇
  2023年   76篇
  2022年   157篇
  2021年   174篇
  2020年   150篇
  2019年   148篇
  2018年   158篇
  2017年   90篇
  2016年   82篇
  2015年   86篇
  2014年   314篇
  2013年   229篇
  2012年   164篇
  2011年   173篇
  2010年   142篇
  2009年   156篇
  2008年   167篇
  2007年   156篇
  2006年   120篇
  2005年   100篇
  2004年   84篇
  2003年   63篇
  2002年   56篇
  2001年   58篇
  2000年   54篇
  1999年   29篇
  1998年   33篇
  1997年   35篇
  1996年   35篇
  1995年   28篇
  1994年   29篇
  1993年   25篇
  1992年   17篇
  1991年   22篇
  1990年   21篇
  1989年   11篇
  1988年   20篇
  1987年   17篇
  1986年   12篇
  1985年   8篇
  1984年   11篇
  1983年   6篇
  1982年   7篇
  1981年   3篇
  1980年   6篇
  1979年   7篇
  1978年   5篇
  1976年   2篇
  1975年   2篇
  1973年   3篇
排序方式: 共有3557条查询结果,搜索用时 15 毫秒
11.
IntroductionThe difference in outcome between right (RCD) and left colonic diverticulitis (LCD) is not well established. The aim of this study was to analyse the presentation and surgical outcome of RCD versus left-sided disease following emergency surgery.MethodWe conducted a retrospective review of patients presenting with acute diverticulitis over a 10-year period from 2004 to 2014 to a tertiary unit. Patient demographics, Hinchey classification, need for emergency surgery, perioperative outcome and recurrence were evaluated.ResultsIn total 360 patients presented with acute diverticulitis, 218 (61%) were right-sided and 142 (39%) were left-sided. The mean age (57 yrs vs 68 yrs) and median length of stay (4 days vs 5 days) were significantly less in RCD (p < 0.001). The need for emergency surgery was similar between RCD and LCD (30.7% vs 23.2%, p = 0.12). Sixty-seven (31%) patients with RCD required emergency surgery, 42 (62.7%) of these were based on a presumptive diagnosis of appendicitis and underwent laparoscopic appendicectomy only. Operative morbidity (10.4% vs 51.5%, p < 0.001) and mortality were significantly higher in LCD (1.5% v 15.2%, p = 0.007). Subgroup analysis of non-appendicectomy, RCD patients, showed LCD were more likely to require surgery (11.5% vs 23.2%, p = 0.003). There was no difference in recurrence (p = 0.6).ConclusionRight colonic diverticulitis patients are younger and disease course is more benign compared to LCD. Presentation can be confused with appendicitis without proper imaging. In the rare cases where emergency surgery is required, RCD is associated with a lower operative morbidity and mortality compared to left-sided disease.  相似文献   
12.
右前外胸部小切口行心脏不停跳心内直视手术   总被引:2,自引:0,他引:2  
目的 介绍27例右前外胸部小切口心脏不停跳体外循环心内直视手术的体会。方法:采用右前外胸部小切口27例中,男16例,女11例,年龄1.8-42岁,皮肤切口全长,儿童为8-10cm,成人10-15cm,第四肋间入胸,在全麻浅低温心脏不停跳体外循环下进行,其中房缺3例,原发孔房缺(P-ASD)1例,室缺(VSD)16例,室缺伴右室流出道狭窄(VSD+RVOT)1例,二尖瓣置换2例,主动脉瓣置换术3例。  相似文献   
13.
Electrocardiography results were used to assess diagnosis andevolution of arrhythmogenic right ventricular disease. The initialECG presentation and long-term changes were analysed in 74consecutivepatients with symptomatic ventricular tachycardia and arrhythmogenicright ventricular disease. On first available tracings, a left axis deviation of the QRSwas found in 18 patients. The QRS length in V1 was 110 ms in39 patients, an epsilon wave was present in 17, and a completenght bundle branch block in four patients. The T wave was negativein V1–V3 in 37 patients (50%). In 36 patients, long-term electrocardiographic follow-up of9.5 ± 3.2 years was available. During this period, ECGchanges were observed in 20 patients (56%):negative T wavesin 11 patients, a new left axis deviation in three, QRS enlargementin 13 (including eight right bundle branch block), right atrialhypertrophy in three, and paroxysmal or established atrial fibrillationin three. On studying all 110 ECG tracings (74 initial recordings +36follow-up ECGs), we found a strong correlation between QRS orT wave changes and the length of follow-up after the first symptom;mean time interval between first ventricular tachycardia andECG recording was significantly longer in patients with negativeT waves in the right precordial leads, QRS enlargement, or leftaxis deviation, than in patients without such abnormalities.ECG abnormalities were more frequent at 10 year and 5 year follow-upthan on initial tracings. A normal ECG was found in 40% of patientsduring the first year of follow-up, 8% at 5 years, and neverlater than the 6th year. In conclusion, electrocardiographic diagnosis of arrhythmogenicright ventricular disease may be difficult in the initial stageof the disease, since a normal ECG is found in up to 40% ofpatients. During the follow-up, progressive and characteristicECG changes will occur. Arrhythmogenic right ventricular diseasecan be excluded if the ECG is found to be normal 6 years orlater after a first ventricular tachycardia attack.  相似文献   
14.
Three cases with anomalous insertion of the superior or inferior vena cava into the right atrium are presented. One case was a 25-year-old healthy man with anomalous low insertion of the right superior vena cava into the right atrium. The remaining two cases were infants with complex cardiac anomalies showing anomalous high insertion of the inferior vena cava into the right atrium. The congenital anomalies of the connection between the superior and the inferior vena cava and the right atrium are rare. Angiographic and computed tomographic findings of these anomalies were reported.  相似文献   
15.
药品集中招标采购:公共政策分析与求解   总被引:1,自引:0,他引:1  
林光祺  周艳 《中国卫生事业管理》2004,20(11):692-693,701
针对我国药品集中招标采购实施过程中的现实困境,文章从利益主体各方力量严重失衡、中介代理机构外部力量失效等角度作出政策分析.在此基础上,作者考量和判断了药品集中招标采购政策的改革形势,并从制度本身的完善、相关制度改革的深化以及政府监管等方面提出对策建议.  相似文献   
16.
静脉药瘾者心内膜炎11例临床分析   总被引:1,自引:0,他引:1  
目的探讨静脉药瘾并发感染性心内膜炎(infective endocarditis IE)的特征。方法回顾分析11例静脉药瘾并发IE的临床资料。结果静脉药瘾并发IE者多为青年男性,男女比例10∶1,平均年龄26岁,无基础心脏病。临床特点起病为发热,体温38~40℃,为不规则发热,全身乏力,面色苍白,咳嗽气促,合并肺感染(91%);血细菌培养阳性以金黄色葡萄球菌多见(45.3%);超声心动图显示右心系统感染(三尖瓣受累)最为常见(81%),其次二尖瓣(18%)。结论静脉药瘾并发IE者临床特征为发热、咳嗽、气促,心脏杂音,血细菌培养阳性合并肺感染,超声心动图检查对右心感染有重要价值。  相似文献   
17.
【摘要】 目的 应用单心动周期实时三维超声心动图(sRT3DE)评价房间隔缺损 (ASD)患者治疗前后右心室收缩功能及其影响因素。方法 选取本院2017年1月~2018年6月收治的45例ASD患者为ASD组,45例健康志愿者为对照组。比较两组二维超声测量右心室舒张末内径(RVd)与右心室面积变化分数(RVFAC),sRT3DE测量右心室舒张末容积(RVEDV)、右心室收缩末容积(RVESV)、右心室每搏量(RVSV)、右心室射血分数(RVEF),比较ASD组封堵术前后及对照组右室收缩功能参数之间的差异,并分析RVEF与ASD大小、RVEDV、RVESV、RVSVASD的相关性,以及RVEF与RVFAC间相关性。结果 RVd、RVEDV、RVESV、RVSV测值比较,ASD术前>ASD术后>对照组,差异有统计学意义(P<001);RVFAC与RVEF测值比较,ASD术前<ASD术后<对照组,差异有统计学意义(P<001)。ASD治疗前RVEF与ASD大小、RVEDV、RVESV呈负相关(r= 0439、 0310、 0688,P<005),与RVSV无相关性(P>005)。RVEF与FAC呈良好正相关(r=0853,P<005)。结论 sRT3DE能准确评价ASD治疗前后右心室收缩功能,ASD右室收缩功能与RVESV具有良好相关性。  相似文献   
18.
目的观察-6°头低位卧床(HDT-6°)对肺循环血流的影响,并探讨其与肺弥散功能的关系。方法采用YK-10循环系统监测仪和HP2500超声诊断仪,对16名健康男性受试者90minHDT-6°卧床及21dHDT-6°卧床前、后及卧床不同时间肺循环血流、肺血容量、右心输出量等有关指标分别进行了测试。结果在90min卧床试验中,HDT-6°卧床肺血容量较卧床前坐位显著增加,随卧床时间延长,肺血容量渐减少,90min左右已显著少于平卧位水平。在21d卧床中,第3天最低,第7天测量仍显著低于卧床前平卧位对照值,以后保持相对稳定。起床后第3天平卧位测量仍低于卧床前。右心输出量在卧床第3天即显著下降,之后保持相对稳定,在起床第3天测量基本恢复;每搏量在卧床第7天显著降低,一直持续到起床第3天,而在这个阶段,心率则逐渐增加,卧床第20天和起床第1、3天均比卧床前有显著增加。结论头低位卧床使肺血流量增加的同时,增加了肺循环的灌注压,有肺间质水肿的潜在危害。同时肺动脉压升高,以及机体通过神经体液的自我调节,反过来减少了肺灌注,肺毛细血管血量的减少,有自我保护的作用。  相似文献   
19.
Fetal stroke is an important cause of cerebral palsy but is difficult to diagnose unless imaging is undertaken in pregnancies at risk because of known maternal or fetal disorders. Fetal ultrasound or magnetic resonance imaging may show haemorrhage or ischaemic lesions including multicystic encephalomalacia and focal porencephaly. Serial imaging has shown the development of malformations including schizencephaly and polymicrogyra after ischaemic and haemorrhagic stroke. Recognised causes of haemorrhagic fetal stroke include alloimmune and autoimmune thrombocytopaenia, maternal and fetal clotting disorders and trauma but these are relatively rare. It is likely that a significant proportion of periventricular and intraventricular haemorrhages are of venous origin. Recent evidence highlights the importance of arterial endothelial dysfunction, rather than thrombocytopaenia, in the intraparenchymal haemorrhage of alloimmune thrombocytopaenia. In the context of placental anastomoses, monochorionic diamniotic twins are at risk of twin twin transfusion syndrome (TTTS), or partial forms including Twin Oligohydramnios Polyhydramnios Sequence (TOPS), differences in estimated weight (selective Intrauterine growth Retardation; sIUGR), or in fetal haemoglobin (Twin Anaemia Polycythaemia Sequence; TAPS). There is a very wide range of ischaemic and haemorrhagic injury in a focal as well as a global distribution. Acute twin twin transfusion may account for intraventricular haemorrhage in recipients and periventricular leukomalacia in donors but there are additional risk factors for focal embolism and cerebrovascular disease. The recipient has circulatory overload, with effects on systemic and pulmonary circulations which probably lead to systemic and pulmonary hypertension and even right ventricular outflow tract obstruction as well as the polycythaemia which is a risk factor for thrombosis and vasculopathy. The donor is hypovolaemic and has a reticulocytosis in response to the anaemia while maternal hypertension and diabetes may influence stroke risk. Understanding of the mechanisms, including the role of vasculopathy, in well studied conditions such as alloimmune thrombocytopaenia and monochorionic diamniotic twinning may lead to reduction of the burden of antenatally sustained cerebral palsy.  相似文献   
20.
From January 1976 to October 1986, 107 cases of esophageal atresia (EA) were admitted to the Neonatal Surgical Unit of the Bambino Gesú Hospital of Rome; 86% of the children had a type III EA. Associated anomalies were present in 47%; they were multiple in 18%. Cardiological malformations were the most frequent followed by digestive, skeletal, urological, and chromosomal aberrations. Surgical treatment was attempted in all children except 3, who died before surgical correction, in an effort to perform an end-to-end anastomosis in a single layer through a transpleural approach. According to the results, children were divided into two groups of 50 patients each: group 1 (1976–1981); and group 2 (1981–1986). Anastomosis was possible in 69% of children (68.7% in group 1, 69.3% in group 2). After 1983, gastrostomy fell into gradual disrepute and a transanastomotic tube was used. Immediate complications were seen in 36.6% of cases; in no case did recurrence of the tracheoesophageal fistula occur. The overall mortality decreased from 50% (group 1) to 30% (group 2). In the two periods considered, the mortality according to Waterston's risk classes was 28.5% 5,8% (class A), 42.1% 11.7% (class B), 82.3% 68.7% (class C). Of a total of 41 deaths, 47% were due to severe associated malformations: bronchopneumopathy or prematurity seemed to have less importance in establishing the prognosis.Offprint requests to: P. Bagolan  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