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   807篇
  免费   53篇
  国内免费   7篇
耳鼻咽喉   1篇
儿科学   45篇
妇产科学   2篇
基础医学   82篇
口腔科学   18篇
临床医学   73篇
内科学   268篇
皮肤病学   8篇
神经病学   42篇
特种医学   83篇
外科学   90篇
综合类   64篇
预防医学   30篇
眼科学   8篇
药学   31篇
肿瘤学   22篇
  2024年   2篇
  2023年   2篇
  2022年   5篇
  2021年   10篇
  2020年   6篇
  2019年   9篇
  2018年   12篇
  2017年   7篇
  2016年   11篇
  2015年   21篇
  2014年   22篇
  2013年   28篇
  2012年   26篇
  2011年   26篇
  2010年   28篇
  2009年   44篇
  2008年   27篇
  2007年   47篇
  2006年   47篇
  2005年   25篇
  2004年   34篇
  2003年   19篇
  2002年   22篇
  2001年   21篇
  2000年   16篇
  1999年   18篇
  1998年   44篇
  1997年   32篇
  1996年   42篇
  1995年   19篇
  1994年   20篇
  1993年   24篇
  1992年   6篇
  1991年   10篇
  1990年   6篇
  1989年   16篇
  1988年   26篇
  1987年   11篇
  1986年   10篇
  1985年   23篇
  1984年   12篇
  1983年   4篇
  1982年   3篇
  1981年   3篇
  1980年   3篇
  1979年   2篇
  1978年   2篇
  1977年   3篇
  1976年   5篇
  1975年   3篇
排序方式: 共有867条查询结果,搜索用时 0 毫秒
51.
OBJECTIVE: We evaluated, in a randomized controlled trial, the safety and effectiveness of intraoperative cell salvage and autotransfusion of washed salvaged red blood cells after first-time coronary artery bypass grafting performed on the beating heart. METHODS: Sixty-one patients undergoing off-pump coronary artery bypass grafting surgery were prospectively randomized to autotransfusion (n = 30; receiving autotransfused washed blood from intraoperative cell salvage) or control (n = 31; receiving homologous blood only as blood-replacement therapy). Homologous blood was given according to unit protocols. RESULTS: The groups were well matched with respect to demographic and comorbid characteristics. Patients in the autotransfusion group had a significantly higher 24-hour postoperative hemoglobin concentration (11.9 g/dL; SD, 1.41 g/dL) than those in the control group (10.5 g/dL; SD, 1.37 g/dL) (mean difference, 1.02 g/dL; 95% confidence interval, 1.60-0.44 g/dL; P = .0007), as well as a 20% reduction in the frequency of homologous blood product use (11/31 vs 5/30; P = .095). Autotransfusion of washed red blood cells was not associated with any derangement of thromboelastograph values or laboratory measures of clotting pathway function (prothrombin time, activated partial thromboplastin time, and fibrinogen levels), increased postoperative bleeding, fluid requirements, or adverse clinical events. There was no statistical difference between groups in the total operation, hospitalization, and management costs per patient (median difference, USD 1015.90; 95% confidence interval, -USD 2260 to USD 206; P = .11). Conclusions Intraoperative cell salvage and autotransfusion was associated with higher postoperative hemoglobin concentrations, a modest reduction in transfusion requirements, no adverse clinical or coagulopathic effects, and no significant increase in cost compared with controls. This study supports its routine use in off-pump coronary artery bypass grafting surgery.  相似文献   
52.
53.
BACKGROUND: Tourette's syndrome (TS) is a neurodevelopmental disorder associated with fronto-striatal dysfunction. There is debate as to the extent to which TS is associated with cognitive impairment. Some authors argue that any impairments seen are attributable to comorbid psychiatric symptomatology, whilst others have suggested that uncomplicated TS is associated with mild deficits limited primarily to inhibitory processes. The present study was designed to examine this issue using carefully screened participants with TS and experimental measures thought to involve different areas of the frontal lobes. METHODS: Adolescents with TS who were screened for comorbid psychiatric disorder were compared with a healthy control group on a set of executive measures. Two tasks involving behavioural inhibition were used: a Sentence Completion task in which sentences had to be completed first with straightforward and then with nonsensical endings, and a Flanker task in which a central stimulus was surrounded by either compatible or incompatible flankers. Working memory was assessed using an N-back task, and reward learning was assessed using a Gambling task. Both accuracy and reaction times were measured for each task. RESULTS: The TS group differed significantly from the control group on both the Sentence Completion task and on the Flanker task. On the Sentence Completion task, they were slower to make both sensible and nonsensical completions, and they had higher error scores on the nonsensical completions. On the Flanker task, the TS participants were less accurate than the control group, since they were poorer on the incompatible but not the compatible trials. A similar interaction with trial type was found for speed, where the TS participants were slowed more by the incompatible versus compatible trials, although overall their performance tended to be faster than the controls. The TS group did not differ significantly from the control group on measures of working memory or reward learning. CONCLUSIONS: The findings provide further evidence that uncomplicated TS is not associated with widespread executive impairments. However, it was not clear that any differences between the groups could be attributed solely to selective inhibitory impairment.  相似文献   
54.
The hph-1 ENU-mutant mouse provides a model of tetrahydrobiopterin deficiency for studying hyperphenylalaninaemia, dopa-response dystonia, and vascular dysfunction. We have successively localized the hph-1 mutation to a congenic interval of 1.6-2.8 Mb, containing the GCH gene encoding GTP cyclohydrolase I (GTP-CH I). We used these data to establish a PCR method for genotyping wild type, hph-1 and heterozygote mice, and found that heterozygote animals have partial tetrahydrobiopterin deficiency. These new findings will extend the utility of the hph-1 mouse in studies of GTP-CH I deficiency.  相似文献   
55.
Executive function,memory, and learning in Tourette's syndrome   总被引:7,自引:0,他引:7  
Young people with Tourette's syndrome (TS) alone, TS plus attention-deficit/hyperactivity disorder (+ADHD), or TS plus obsessive-compulsive disorder (+OCD) were compared with a healthy control group on a set of measures of executive functioning, memory, and learning. The TS-alone group was impaired on one executive measure involving inhibition and strategy generation but did not differ significantly from the healthy control group on other measures. The TS+ADHD group showed impairment on several executive measures. There was no evidence of impairment in implicit aspects of memory and learning for any of the TS groups. The findings are discussed in terms of the frontostriatal hypothesis of TS and the contribution of comorbid symptomatology.  相似文献   
56.
57.
58.
59.
A group of 99 babies born in hospital and subsequently transferred to the special care unit were examined for the presence of candidas orally. The rate of isolation rose from 6% neonatally to 53% on day 14 of life. Among infants who did not harbour the organisms when discharged from hospital, colonization rapidly took place so that 79% did so at 4 weeks of age, after which the rate fell to 50% at one year of age. The low incidence of clinical candidosis suggests that in these babies as in other groups C. albicans is normally a harmless commensal.  相似文献   
60.
Eight cases of dermatomyositis in children admitted to Scottish hospitals between 1962 and 1972 have been reviewed. 6 of the 8 were currently in complete remission. In the other 2 cases the disease remained active in 1 and 1 had died of cardiac failure 6 years after the onset of disease. 5 had developed extensive soft tissue calcification for which 2 were treated with ethanehydroxydiphosphonate, one showing definite improvement and the other no change. All had been treated with corticosteroids and two in addition had had cytotoxic agents (methotrexate or cyclophosphamide). The overal prognosis had probably been improved by the use of corticosteroids but not by the cytotoxic drugs. Only one of the patients was incapacitated by residual contractures or calcinosis.  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