全文获取类型
收费全文 | 60001篇 |
免费 | 5079篇 |
国内免费 | 119篇 |
专业分类
耳鼻咽喉 | 517篇 |
儿科学 | 2449篇 |
妇产科学 | 1696篇 |
基础医学 | 7979篇 |
口腔科学 | 777篇 |
临床医学 | 7219篇 |
内科学 | 11263篇 |
皮肤病学 | 970篇 |
神经病学 | 6279篇 |
特种医学 | 1592篇 |
外国民族医学 | 1篇 |
外科学 | 6537篇 |
综合类 | 871篇 |
现状与发展 | 1篇 |
一般理论 | 85篇 |
预防医学 | 7487篇 |
眼科学 | 1445篇 |
药学 | 3978篇 |
中国医学 | 54篇 |
肿瘤学 | 3999篇 |
出版年
2023年 | 726篇 |
2022年 | 1118篇 |
2021年 | 2307篇 |
2020年 | 1367篇 |
2019年 | 2043篇 |
2018年 | 2319篇 |
2017年 | 1593篇 |
2016年 | 1780篇 |
2015年 | 1920篇 |
2014年 | 2528篇 |
2013年 | 3247篇 |
2012年 | 4740篇 |
2011年 | 4642篇 |
2010年 | 2385篇 |
2009年 | 2137篇 |
2008年 | 3381篇 |
2007年 | 3526篇 |
2006年 | 3126篇 |
2005年 | 2868篇 |
2004年 | 2635篇 |
2003年 | 2290篇 |
2002年 | 2125篇 |
2001年 | 688篇 |
2000年 | 680篇 |
1999年 | 686篇 |
1998年 | 468篇 |
1997年 | 363篇 |
1996年 | 302篇 |
1995年 | 321篇 |
1994年 | 298篇 |
1993年 | 290篇 |
1992年 | 454篇 |
1991年 | 460篇 |
1990年 | 430篇 |
1989年 | 409篇 |
1988年 | 352篇 |
1987年 | 341篇 |
1986年 | 353篇 |
1985年 | 342篇 |
1984年 | 271篇 |
1983年 | 217篇 |
1982年 | 179篇 |
1981年 | 160篇 |
1980年 | 164篇 |
1979年 | 198篇 |
1978年 | 157篇 |
1977年 | 150篇 |
1974年 | 142篇 |
1973年 | 142篇 |
1971年 | 125篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
122.
Kevin O'Brien Jean Wright Frances Conboy YeWeng Sanjie Nicky Mandall Stephen Chadwick Ivan Connolly Paul Cook David Birnie Mark Hammond Nigel Harradine David Lewis Cathy McDade Laura Mitchell Alison Murray Julian O'Neill Mike Read Stephen Robinson Dai Roberts-Harry Jonathan Sandler Ian Shaw 《American journal of orthodontics and dentofacial orthopedics》2003,124(3):234-43; quiz 339
This study evaluated the effectiveness of early orthodontic treatment with the Twin-block appliance for the developing Class II Division 1 malocclusion. This multicenter trial was carried out in the United Kingdom. A total of 174 children, aged 8 to 10 years old, with Class II Division 1 malocclusion were randomly allocated to receive treatment with a Twin-block appliance or to an untreated, control group. Data were collected at the start of the study and 15 months later. Results showed that early treatment with Twin-block appliances resulted in reduction of overjet, correction of molar relationships, and reduction in severity of malocclusion. Most of this correction was due to dentoalveolar change, but some was due to favorable skeletal change. Early treatment with the Twin-block appliance is effective in reducing overjet and severity of malocclusion. The small change in the skeletal relationship might not be considered clinically significant. 相似文献
123.
Jean-Pierre Chanoine MD PhD Sarah Hampl MD FAAP Craig Jensen MD Mark Boldrin MS Jonathan Hauptman MD 李呈亿 《美国医学会杂志》2006,25(1):34-43
背景:儿童和青少年超重和肥胖正迅速增加。在该人群,单纯行为疗法减肥及维持体重下降的效果有限,但是对药物治疗尚未进行广泛的研究。
目的:确定奥利州他(Orlistat)在青少年体重治疗方面的效果及其安个性。
设计、地点和病例:于美国和加拿大32个中心、539例肥胖青少年(12—16岁;体重指数[body mass index,BMI]在第95百分化之上≥2单位)进行的多ln0、54剧(2000年8月至2002年10月)随机双盲研究。
干预:给予奥利司他(n=357)或安慰剂(n=182)120mg,每口3次,持续1年;加适度低热卡饮食(脂肪占30%)、运动和行为治疗。
主要观察指标:BMI变化;二级指标包括腰围和髋用、体重下降、脂质测量以及机体对口服葡萄糖的血糖和胰岛素反心。
结果:至12周时,两组BMI均有下降;此后,奥利司他组体重维持稳定而安慰剂组则超过基线。研究结束时,奥利司他组BMI下降0.55。而安慰剂组则增加0.31(P=0.001)。与安慰剂组的15.7%相比,奥利司他组26.5%的病例BMI下降≥5%(P=0.005);BMI下降≥10%者分别为4.5%和13.3%(P=0.002)。在研究结束时,奥利司他组体重增加0.53kg,安慰剂组增加3.14kg(P〈0.001)。双能X线吸收测量娃示,这种差异可用脂肪体再的变化解释。奥利司他组腰围下降,安慰剂组腰围上升(-1.33cm比+0.12cm;P〈0.05)。奥利司他组发生轻至中度胃肠道不良事件者为9%-50%,安慰剂组为1%~13%。
结论:与安慰剂比较,奥利司他与饮食、运动和行为改善联合可显著改善肥胖青少年体重的治疗。在这个青少年人群,连续使用奥利司他1年并无重要安全问题,尽管奥利司他组胃肠道不良事件较为常见。 相似文献
124.
125.
Endovascular treatment of cerebral aneuryms is now widely used and has important implications for the neuroanaesthetist. Significant issues include the decision to use general anaesthesia, factors associated with anaesthesia in the interventional radiology suite and treatment of complications. As endovascular treatment is now supported by evidence and established in practice, neuroanaesthetists should be involved in planning these procedures from a process, and individual patient, perspective. 相似文献
126.
S M Haffner K K Gruber P A Morales H P Hazuda R A Valdez B D Mitchell M P Stern 《American journal of epidemiology》1992,136(9):1060-1068
There is considerable evidence that lipoprotein(a) (Lp(a)) is a strong independent risk factor for coronary heart disease. Based on their risk factor profile, Mexican Americans have an increased risk of coronary heart disease, yet Mexican Americans have coronary heart disease mortality similar to or lower than that of non-Hispanic whites. The authors therefore attempted to determine whether Mexican Americans had decreased Lp(a) concentrations relative to non-Hispanic whites in the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. Lp(a) concentrations (mg/dl) were significantly lower in Mexican Americans (n = 316) than in non-Hispanic whites (n = 242) (men: 10.4 vs. 16.3; women: 11.5 vs. 16.4). In addition, the proportion of persons with Lp(a) concentrations of > or = 30 mg/dl (the threshold at which increased risk of coronary heart disease is believed to occur) was significantly higher in non-Hispanic whites than in Mexican Americans (18.6% vs. 7.6%; Mantel-Haenszel odds ratio (adjusted for sex) = 2.79). Age, obesity, body fat distribution, cigarette smoking, alcohol consumption, and glucose and insulin concentrations were not significantly related to Lp(a) levels. Decreased Lp(a) concentrations may account in part for Mexican Americans' relative protection from coronary heart disease mortality. 相似文献
127.
Controlled study of meso-2,3-dimercaptosuccinic acid for the management of childhood lead intoxication. 总被引:7,自引:0,他引:7
J H Graziano N J Lolacono T Moulton M E Mitchell V Slavkovich C Zarate 《The Journal of pediatrics》1992,120(1):133-139
We examined the efficacy and safety of meso-2,3-dimercaptosuccinic acid (DMSA) in children with markedly elevated blood lead (BPb) concentrations. Among 19 children with BPb concentrations of 50 to 69 micrograms/dl (2.41 to 3.33 mumol/L) who received a 5-day inpatient oral course of DMSA (1050 mg/m2 per day), the mean BPb concentration decreased by 61%; in four who received calcium disodium ethylenediaminetetraacetic acid (CaNa2EDTA) (1000 mg/m2 per day intravenously), it decreased by 45% (p less than 0.0007). Urinary lead excretion was comparable in both groups. Treatment with DMSA was more effective than treatment with CaNa2EDTA in restoring metabolic activity to the heme pathway and was well tolerated even among nine patients who received concomitant iron supplementation and two who had homozygous deficiency of glucose-6-phosphate dehydrogenase. On discharge, these 19 children received either no chelation therapy or DMSA, 350 or 700 mg/m2 per day for 14 days on an outpatient basis. After 14 days the mean BPb values for the no-chelation, low-DMSA, and high-DMSA groups were 73%, 66%, and 50% of the pretreatment values, respectively. We conclude that a 5-day oral course of DMSA is effective in the treatment of children with severe lead poisoning. In addition, on an outpatient basis the administration of DMSA, 700 mg/m2 per day, is capable of delaying the typical rebound in BPb values and should ultimately reduce the need for repeated hospitalizations. 相似文献
128.
129.
130.
Although cardiac arrhythmias remain a serious clinical problem in many patients with heart disease, the exact role of antiarrhythmic drug therapy is currently under intense evaluation. Within the last several years it has become clear that there are significant risks as well as potential benefits associated with existing agents. Ongoing studies in large patient populations should help determine the benefit/risk ratio of traditional therapy. Regardless of the outcome of these trials, current electrophysiological dogma will have to be re-evaluated and newer concepts evolve for drug development to make further progress. The goal of this symposium is to exchange information among basic and clinical investigators so as to facilitate the emergence of novel electrophysiological concepts that will form the basis for future generations of antiarrhythmic drugs. 相似文献