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   1403篇
  免费   120篇
  国内免费   10篇
耳鼻咽喉   22篇
儿科学   70篇
妇产科学   27篇
基础医学   151篇
口腔科学   46篇
临床医学   145篇
内科学   355篇
皮肤病学   28篇
神经病学   58篇
特种医学   129篇
外科学   189篇
综合类   28篇
预防医学   81篇
眼科学   26篇
药学   58篇
肿瘤学   120篇
  2021年   23篇
  2020年   16篇
  2018年   23篇
  2017年   21篇
  2016年   19篇
  2015年   24篇
  2014年   42篇
  2013年   60篇
  2012年   32篇
  2011年   48篇
  2010年   45篇
  2009年   38篇
  2008年   49篇
  2007年   55篇
  2006年   58篇
  2005年   48篇
  2004年   40篇
  2003年   27篇
  2002年   43篇
  2001年   26篇
  2000年   26篇
  1999年   42篇
  1998年   36篇
  1997年   42篇
  1996年   41篇
  1995年   29篇
  1994年   26篇
  1993年   21篇
  1992年   24篇
  1991年   15篇
  1990年   15篇
  1989年   17篇
  1988年   22篇
  1987年   22篇
  1986年   33篇
  1985年   24篇
  1984年   23篇
  1982年   21篇
  1980年   17篇
  1978年   15篇
  1977年   22篇
  1976年   14篇
  1975年   21篇
  1974年   27篇
  1973年   21篇
  1972年   24篇
  1971年   23篇
  1970年   19篇
  1968年   15篇
  1966年   14篇
排序方式: 共有1533条查询结果,搜索用时 85 毫秒
61.
62.
Objectives. We studied the duration and prognostic significance of atrial arrhythmias in the denervated transplanted heart, specifically the occurrence of atrial fibrillation in the absence of vagal modulation.

Background. Substantial animal data indicate that vagally induced dispersion of atrial refractoriness plays a central role in the induction and maintenance of atrial fibrillation.

Methods. We studied the occurrence of atrial arrhythmias in the denervated hearts of 88 consecutive orthotopic transplantations in 85 patients by means of continuous telemetry and all available electrocardiographic tracings.

Results. Fifty percent of recipients (44 of 88) developed at least one atrial arrhythmia. Atrial fibrillation occurred 23 times (21 recipients), atrial flutter 39 times (26 recipients), ectopic atrial tachycardia 3 times (3 recipients) and supraventricular tachycardia 18 times (11 recipients). The number of atrial fibrillation and atrial flutter episodes did not differ (23 vs. 39, p = 0.072), but the fibrillation (37.0 ± 10 vs. 6.6 ± 3.6 h, p = 0.014). Atrial fibrillation was associated with an increased risk of subsequent death (10 of 21 recipients with vs. 15 of 67 without atrial fibrillation, risk ratio 3.15 ± 0.18, p = 0.005 by Cox proportional hazards model). All 5 recipients who developed “late” atrial fibrillation (>2 weeks after transplantation) died versus 5 of 16 who developed atrial fibrillation within the first 2 weeks (p = 0.007). Causes of death included rejection (three recipients), allograft failure (two recipients), infection (three recipients) and multiorgan failure (two recipients). Atrial fibrillation was not associated with age, gender, ischemic time, reason for transplantation, echocardiographic variables, invasive hemodynamic variables or biopsy grade. Mean time from atrial arrhythmia to echocardiography was 2.7 ± 3.3 days; that to biopsy was 4.8 ± 6.3 days. Atrial flutter was not associated with subsequent death. Only 7 (15.9%) of 44 recipients demonstrated moderate or severe allograft rejection at the time of the arrhythmia.

Conclusions. Atrial arrhythmias occur frequently in the denervated transplanted heart, often in the absence of significant rejection. Late atrial fibrillation may be associated with an increased all-cause mortality.  相似文献   

63.
64.
In a recent issue of Critical Care, Brandt and colleagues report the effects of a 'liberal' fluid loading protocol compared to a more 'restrictive' protocol on hemodynamics and mortality in pigs in which septic shock had been induced. It appears that the former protocol was associated with higher mortality in spite of improved hemodynamics compared to the latter. The results of the paper are discussed here in view of the scope and mechanisms of these findings. With regard to fluid resuscitation, they indicate that too much of an otherwise good thing is harmful, even if overhydration and edema formation seem to have been prevented. They also do not exclude a specific toxic effect of the larger volumes of hydroxyethyl starch in the 'liberal' strategy. The precise nature of a toxic effect remains obscure, however, but may involve the kidneys.  相似文献   
65.
Background Post‐inflammatory hyperpigmentation (PIH) is a common occurrence in patients with acne vulgaris, particularly in those with skin of colour. Aims A previous study has demonstrated the benefit of tretinoin (retinoic acid) in the treatment of PIH; however, there is currently no standard protocol to evaluate change in PIH following treatment. Based on these findings, we performed a pilot, exploratory, blinded, intraindividual‐controlled methodology study that consisted of a photographic assessment protocol with facial mapping. Materials and methods The study was based on a secondary analysis of a phase 4, community‐based trial of 544 acne patients who were treated with tretinoin gel microsphere 0.04% or 0.1%. Only patients with Fitzpatrick types III–V (skin of colour) were included in the study; subjects with Fitzpatrick skin type VI were excluded because the photographic assessment did not allow for proper evaluation. Results Despite the small number of subjects evaluated (n = 25), the results revealed consistent assessment of improvement in PIH between two independent graders (weighted κ = 0.84). Conclusion Further study with a larger population is recommended to validate the accuracy of this method.  相似文献   
66.
BACKGROUND: The use of adjuvant carboplatin in the management of stage I seminoma of the testis has been limited by the lack of long-term data. In this study, we address this issue for the first time. PATIENTS AND METHODS: Data on 199 patients treated with single-agent carboplatin for stage I seminoma of the testis were prospectively collected. Overall mortality, deaths from circulatory disease and the incidence of second cancers were compared with expected values derived from the UK general population. RESULTS: The median follow-up for the cohort was 9.0 years (range 0.1-20.1). There has been no excess in overall mortality [standardised mortality ratio (SMR) 0.89; 95% CI 0.36-1.83], death from circulatory diseases (SMR 1.44; 95% CI 0.39-3.69) or the incidence of second nontestis cancers (standardised incidence ratio 0.96; 95% CI 0.26-2.45) in this group of patients. These findings also applied to specific follow-up periods of >5 or 10 years. Specifically, neither haematological nor solid nontestis tumours occurred in excess. There was an increase in the long-term development of contralateral testis cancers. CONCLUSIONS: This study addresses some of the concerns surrounding the long-term safety of single-agent carboplatin. It also helps in planning long-term follow-up for patients receiving this form of treatment.  相似文献   
67.

Background  

In patients with type 2 diabetes, the risk for cardiovascular disease is substantial. To achieve a more favourable risk profile, lifestyle changes on diet, physical activity and smoking status are needed. This will involve changes in behaviour, which is difficult to achieve. Cognitive behavioural therapies focussing on self-management have been shown to be effective. We have developed an intervention combining techniques of Motivational Interviewing (MI) and Problem Solving Treatment (PST). The aim of our study is to investigate if adding a combined behavioural intervention to managed care, is effective in achieving changes in lifestyle and cardiovascular risk profile.  相似文献   
68.
69.
70.
Postoperative cognitive dysfunction in middle-aged patients   总被引:19,自引:0,他引:19  
BACKGROUND: Postoperative cognitive dysfunction (POCD) after noncardiac surgery is strongly associated with increasing age in elderly patients; middle-aged patients (aged 40-60 yr) may be expected to have a lower incidence, although subjective complaints are frequent. METHODS: The authors compared the changes in neuropsychological test results at 1 week and 3 months in patients aged 40-60 yr, using a battery of neuropsychological tests, with those of age-matched control subjects using Z-score analysis. They assessed risk factors and associations of POCD with measures of subjective cognitive function, depression, and activities of daily living. RESULTS: At 7 days, cognitive dysfunction as defined was present in 19.2% (confidence interval [CI], 15.7-23.1) of the patients and in 4.0% (CI, 1.6-8.0) of control subjects (P < 0.001). After 3 months, the incidence was 6.2% (CI, 4.1-8.9) in patients and 4.1% (CI, 1.7-8.4) in control subjects (not significant). POCD at 7 days was associated with supplementary epidural analgesia and reported avoidance of alcohol consumption. At 3 months, 29% of patients had subjective symptoms of POCD, and this finding was associated with depression. Early POCD was associated with reports of lower activity scores at 3 months. CONCLUSIONS: Postoperative cognitive dysfunction occurs frequently but resolves by 3 months after surgery. It may be associated with decreased activity during this period. Subjective report overestimates the incidence of POCD. Patients may be helped by recognition that the problem is genuine and reassured that it is likely to be transient.  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