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   21046篇
  免费   1504篇
  国内免费   79篇
耳鼻咽喉   309篇
儿科学   481篇
妇产科学   451篇
基础医学   3209篇
口腔科学   476篇
临床医学   2220篇
内科学   4181篇
皮肤病学   367篇
神经病学   2180篇
特种医学   947篇
外国民族医学   1篇
外科学   2927篇
综合类   209篇
一般理论   50篇
预防医学   1550篇
眼科学   450篇
药学   1360篇
中国医学   22篇
肿瘤学   1239篇
  2023年   109篇
  2022年   144篇
  2021年   526篇
  2020年   278篇
  2019年   480篇
  2018年   547篇
  2017年   406篇
  2016年   433篇
  2015年   510篇
  2014年   643篇
  2013年   1052篇
  2012年   1358篇
  2011年   1521篇
  2010年   816篇
  2009年   703篇
  2008年   1159篇
  2007年   1190篇
  2006年   1110篇
  2005年   1077篇
  2004年   1091篇
  2003年   960篇
  2002年   987篇
  2001年   189篇
  2000年   149篇
  1999年   189篇
  1998年   247篇
  1997年   204篇
  1996年   183篇
  1995年   173篇
  1994年   164篇
  1993年   141篇
  1992年   120篇
  1991年   109篇
  1990年   108篇
  1989年   121篇
  1988年   113篇
  1987年   113篇
  1986年   92篇
  1985年   110篇
  1984年   123篇
  1983年   103篇
  1982年   164篇
  1981年   136篇
  1980年   139篇
  1979年   85篇
  1978年   89篇
  1977年   87篇
  1976年   75篇
  1974年   88篇
  1973年   67篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Graefe's Archive for Clinical and Experimental Ophthalmology -  相似文献   
3.
4.
Hyperhidrosis can seriously impair patients’ quality of life. Medical history, including heredity and hyperhidrosis during youth, as well as current age and time elapsed since menopause, is important to consider when distinguishing between postmenopausal hyperhidrosis and vasomotor symptoms to enable adequate treatment. This report concerns a subgroup of eight postmenopausal patients participating in a randomized controlled trial regarding botulinum toxin (Btx) type B treatment in craniofacial hyperhidrosis. Even though the sample size is small and the enrolment is not yet completed, the promising data collected hitherto are interesting to present in advance because this subtype of craniofacial hyperhidrosis is often underrecognized and challenging to treat. Patients were randomized to receive Btx type B or placebo. Measurements were performed before treatment and 3 ± 1 weeks after. The Dermatology Life Quality Index (DLQI) score was improved for all patients after Btx type B treatment (n = 3) with a median decrease of 9 points (90% median improvement). The placebo group (n = 5) had a median increase of 2 points (–18% median decline). When the same group (n = 5) received Btx type B (open) the DLQI score decreased with a median of 7 points compared with baseline (91% median improvement). Treatment‐related adverse events were temporary and did not prevent improvement of life quality. Furthermore, background data evaluation uncovered interesting findings regarding vasomotor symptoms in relation to postmenopausal hyperhidrosis. In conclusion, the results indicated that Btx type B seems to be a safe and effective treatment in postmenopausal craniofacial hyperhidrosis. Further research is encouraged.  相似文献   
5.
6.

Background

Physicians treating nonvalvular atrial fibrillation (AF) assess stroke and bleeding risks when deciding on anticoagulation. The agreement between empirical and physician-estimated risks is unclear. Furthermore, the association between patient and physician sex and anticoagulation decision-making is uncertain.

Methods

We pooled data from 2 national primary care physician chart audit databases of patients with AF (Facilitating Review and Education to Optimize Stroke Prevention in Atrial Fibrillation and Coordinated National Network to Engage Physicians in the Care and Treatment of Patients with Atrial Fibrillation Chart Audit) with a combined 1035 physicians (133 female, 902 male) and 10,927 patients (4567 female and 6360 male).

Results

Male physicians underestimated stroke risk in female patients and overestimated risk in male patients. Female physicians estimated stroke risk well in female patients but underestimated the risk in male patients. Risk of bleeding was underestimated in all. Despite differences in risk assessment by physician and patient sex, > 90% of patients received anticoagulation across all subgroups. There was modest agreement between physician estimated and calculated (ie, CHADS2 score) stroke risk: Kappa scores were 0.41 (0.35-0.47) for female physicians and 0.34 (0.32-0.36) for male physicians.

Conclusions

Our study is the first to examine the association between patient and physician sex influences and stroke and bleeding risk estimation in AF. Although there were differences in agreement between physician estimated stroke risk and calculated CHADS2 scores, these differences were small and unlikely to affect clinical practice; further, despite any perceived differences in the accuracy of risk assessment by sex, most patients received anticoagulation.  相似文献   
7.
Marie Warrer Petersen  Tine Sylvest Meyhoff  Marie Helleberg  Maj-Brit Nørregaard Kjær  Anders Granholm  Carl Johan Steensen Hjortsø  Thomas Steen Jensen  Morten Hylander Møller  Peter Buhl Hjortrup  Mik Wetterslev  Gitte Kingo Vesterlund  Lene Russell  Vibeke Lind Jørgensen  Klaus Tjelle  Thomas Benfield  Charlotte Suppli Ulrik  Anne Sofie Andreasen  Thomas Mohr  Morten H. Bestle  Lone Musaeus Poulsen  Mette Friberg Hitz  Thomas Hildebrandt  Lene Surland Knudsen  Anders Møller  Christoffer Grant Sølling  Anne Craveiro Brøchner  Bodil Steen Rasmussen  Henrik Nielsen  Steffen Christensen  Thomas Strøm  Maria Cronhjort  Rebecka Rubenson Wahlin  Stephan Jakob  Luca Cioccari  Balasubramanian Venkatesh  Naomi Hammond  Vivekanand Jha  Sheila Nainan Myatra  Christian Gluud  Theis Lange  Anders Perner 《Acta anaesthesiologica Scandinavica》2020,64(9):1365-1375

Introduction

Severe acute respiratory syndrome coronavirus-2 has caused a pandemic of coronavirus disease (COVID-19) with many patients developing hypoxic respiratory failure. Corticosteroids reduce the time on mechanical ventilation, length of stay in the intensive care unit and potentially also mortality in similar patient populations. However, corticosteroids have undesirable effects, including longer time to viral clearance. Clinical equipoise on the use of corticosteroids for COVID-19 exists.

Methods

The COVID STEROID trial is an international, randomised, stratified, blinded clinical trial. We will allocate 1000 adult patients with COVID-19 receiving ≥10 L/min of oxygen or on mechanical ventilation to intravenous hydrocortisone 200 mg daily vs placebo (0.9% saline) for 7 days. The primary outcome is days alive without life support (ie mechanical ventilation, circulatory support, and renal replacement therapy) at day 28. Secondary outcomes are serious adverse reactions at day 14; days alive without life support at day 90; days alive and out of hospital at day 90; all-cause mortality at day 28, day 90, and 1 year; and health-related quality of life at 1 year. We will conduct the statistical analyses according to this protocol, including interim analyses for every 250 patients followed for 28 days. The primary outcome will be compared using the Kryger Jensen and Lange test in the intention to treat population and reported as differences in means and medians with 95% confidence intervals.

Discussion

The COVID STEROID trial will provide important evidence to guide the use of corticosteroids in COVID-19 and severe hypoxia.
  相似文献   
8.
OBJECTIVE: Neighborhood sociodemographic characteristics may be important to the mental health of older adults who have decreased mobility and fewer resources. Our objective was to examine the association between neighborhood context and level of depressive symptomatology in older adults in a diverse geographic region of central North Carolina. METHODS: The sample included 2,998 adults 65 or older residing in 91 census tracts. Depressive symptoms were measured using the Center for Epidemiologic Studies-Depression scale (CES-D). Neighborhoods were characterized by five census-based characteristics: socioeconomic disadvantage, socioeconomic advantage, racial/ethnic heterogeneity, residential stability, and age structure. RESULTS: In ecologic level analyses, level of census tract socioeconomic disadvantage was associated with increased depressive symptoms. To determine whether neighborhood context was associated with depressive symptoms independently of individual characteristics, the authors used multilevel modeling. The authors examined the ability of each of five neighborhood (level 2) characteristics to predict a level 1 outcome (CES-D symptoms) controlling for the effects of individual (level 1) characteristics. Younger age, being widowed, lower income, and having some functional limitations were associated with increased depression symptoms conditional on census tract random effects. However, none of the neighborhood characteristics was significantly associated with depression symptoms, conditional on census tract random effects, either unadjusted or adjusted for individual characteristics. CONCLUSION: Any observed association between neighborhood sociodemographic characteristics and individual depressive symptoms in our sample may reflect the characteristics of the individuals who reside in the neighborhood rather than the neighborhood characteristics themselves. The use of multilevel modeling is important to separate these effects.  相似文献   
9.
The aim of this pilot study was to examine the role of the striatum and cerebellum in the adaptation to a novel movement within a sequence of practiced movements using a motor learning paradigm. The performance of patients in the early or advanced stages of Parkinson's disease (PD) and of patients with damage to the cerebellum (CE) was compared, respectively to a group of aged and young matched controls on an adapted version of the Mirror-Tracing Test. In this task, subjects were required to trace a series of complex figures in two conditions: (1) a Practiced condition, in which the figures were composed of the juxtaposition of three simple designs that were extensively practiced before; and (2) a Mixed condition in which triads were created by replacing the last simple figure of the triads in the Practiced condition by a new simple figure that had never been traced individually before. Results showed that all clinical groups were slower than controls at tracing the Practiced triads. Most interestingly, however, only patients in the advanced stages of PD showed increased completion time to trace the triads in the Mixed condition. This suggests that a bilateral striatal dysfunction affects the ability to adapt to a novel motion within a sequence of practiced movements. Although exploratory, these results support a functional dissociation between the striatum and cerebellum in acquiring visuomotor skilled behaviors.  相似文献   
10.
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