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   561篇
  免费   35篇
  国内免费   1篇
耳鼻咽喉   6篇
儿科学   18篇
妇产科学   11篇
基础医学   52篇
口腔科学   5篇
临床医学   43篇
内科学   124篇
皮肤病学   19篇
神经病学   62篇
特种医学   16篇
外科学   79篇
综合类   1篇
预防医学   85篇
眼科学   9篇
药学   42篇
中国医学   1篇
肿瘤学   24篇
  2024年   2篇
  2023年   5篇
  2022年   12篇
  2021年   33篇
  2020年   11篇
  2019年   25篇
  2018年   21篇
  2017年   18篇
  2016年   19篇
  2015年   20篇
  2014年   26篇
  2013年   27篇
  2012年   37篇
  2011年   44篇
  2010年   23篇
  2009年   28篇
  2008年   49篇
  2007年   37篇
  2006年   28篇
  2005年   20篇
  2004年   14篇
  2003年   13篇
  2002年   14篇
  2001年   9篇
  2000年   9篇
  1999年   7篇
  1998年   3篇
  1996年   4篇
  1995年   4篇
  1994年   7篇
  1993年   2篇
  1992年   4篇
  1991年   3篇
  1990年   2篇
  1989年   1篇
  1988年   2篇
  1987年   2篇
  1985年   4篇
  1984年   2篇
  1983年   2篇
  1974年   1篇
  1973年   1篇
  1968年   1篇
  1967年   1篇
排序方式: 共有597条查询结果,搜索用时 31 毫秒
71.
Progressive myoclonus epilepsy of the Lafora type (Lafora'sdisease) is an autosomal recessive disease characterized byepilepsy, myoclonus, dementia, and periodic acid-Schiff-positiveintracellular inclusion bodies. The inclusion deposits consistof branched polysaccharides (polyglucosans) but the responsiblebiochemical defect has not been identified. Onset is duringlate childhood or adolescence and the disease leads to a fataloutcome within a decade of first symptoms. We studied nine familiesin which Lafora’s disease had been proven by biopsy inat least one member. In order to locate the responsible gene,we screened the human genome with microsatellite markers spacedan average of 13 cM. We used linkage analysis in all nine familiesand homozygosity mapping in four consanguineous families todefine the Lafora‘s disease gene region. Two point linkageanalysis resulted in a total peak lod score of 10.54 for markerD6S311. Six additional chromosome 6q23–25 microsatellitesyielded lod scores ranging from 5.92 to 9.60 at  相似文献   
72.
Expressed Emotion (EE) proved to be the best single predictor of relapse in schizophrenia in 1972. Since then, studies on EE were oriented in three directions: Replication of the original study in different countries, improvement of the methodology and clinical applications. The analysis of different key studies shows that EE is a powerful predictor factor, although it is influenced by other variables such as culture.  相似文献   
73.
74.
Advances in determining the mechanisms that underlie the control of energy balance in mammals have recently been provided by the discovery and characterization of aquaporin-7 (AQP7), a water-glycerol transporter that is present in the plasma membrane of fat-storing cells (adipocytes). Recent studies have shown that the absence of AQP7 expression in fat cells increases glycerol kinase activity, boosting triacylglycerol synthesis and ultimately leading to obesity. Thus, AQP7 operates as a glycerol channel in vivo, whereby adipocyte glycerol permeability has a key role in the regulation of fat accumulation.  相似文献   
75.
Background: Obesity is considered a state of low-grade chronic inflammation, which may favor the development of cardiovascular diseases. Serum amyloid A (SAA) is an acute phase protein synthesized in response to infection, inflammation, injury, and stress. The aim of the present study was to compare the circulating concentrations of SAA and the mRNA expression in omental adipose tissue between lean and obese individuals and to analyze the effect of weight loss after gastric bypass. Methods: 16 lean volunteers (BMI 20.5 ± 0.6 kg/m2) and 24 obese patients (BMI 47.0 ± 1.2 kg/m2) were included in the study. Serum concentrations of SAA were measured by ELISA. In addition, the concentrations of SAA in 18 morbidly obese patients (7 male/11 female; BMI 44.6 ± 1.9 kg/m2) were measured before and after weight loss following Roux-en-Y gastric bypass (RYGBP). SAA expression in omental adipose tissue was quantified by RT-PCR in biopsies from obese patients undergoing RYGBP and from age-matched lean individuals subjected to Nissen fundoplication. Results: Obese patients exhibited significantly increased circulating SAA concentrations (6.6 ± 0.5 vs 39.3 ± 9.1 μg/ml; P<0.01) compared to lean subjects. A significant positive correlation was found between logSAA and body fat (r=0.631, P<0.0001). Obese patients showed significantly increased (P<0.05) mRNA expression of SAA in omental adipose tissue compared to lean subjects. Weight loss significantly decreased SAA concentrations after RYGBP (final BMI 28.5 ± 0.9 kg/m2, P<0.0001 vs initial) from 47.5 ± 14.5 to 15.7 ± 2.9 μg/ml (P<0.05). Conclusion: It can be concluded that serum SAA and mRNA expression of SAA in omental adipose tissue are increased in obese patients contributing to the obesity-associated cardiovascular disease risk. Moreover, weight loss reduces SAA concentrations, which may contribute to the beneficial effects accompanying weight reduction.  相似文献   
76.
77.
78.
Altered neural mechanisms implying autonomic functioning have been described related to anxiety. Pre-competitive stress may be considered as an anxiety-state associated with disorders (i.e. somatic and cognitive alterations, and self-confidence worsening) that severely impair sport performance, conditioning short-lasting strength-related disciplines like BMX. From the psychological perspective, coaches use questionnaires like CSAI-2R to identify these alterations. However, with the emergence of psycho-physiological and non-linear approaches, recent studies suggest that HRV analysis provides a non-invasive tool to assess them. Hence, our purpose was to analyze how BMX competition affects subjective perception of anxiety, and if this emotional alteration is reflected in HR dynamics, analyzed both linear and nonlinearly, exploring the evolution of this relationship in a 2-day competition. Eleven male athletes from the BMX Spanish National Team were assessed from baseline HRV the morning of a training session (rT) and on two successive days of competition (rC1 and rC2), repeating HRV recording with CSAI-2R 20 min prior to training (aT) and competition (pre-competitive: aC1 and aC2). Repeated measures MANOVA showed significant vagal slow-down responses in aC1 and aC2 comparing not only with aT, but also comparing with rT, rC1 and rC2, coinciding with significant greater scores for the somatic and cognitive anxiety (SA and CA) in aC1 and aC2 versus aT. Pearson analysis showed a large and positive correlation between α1 and SA in C1, and close to it between SampEn and CA in aC2; both were confirmed by Bland–Altman chart analysis. Our results confirm that HRV analysis provide a complementary tool to assess competitive pressure.  相似文献   
79.
80.
RATIONALE: Objective strategies are needed to improve the diagnosis of severe community-acquired pneumonia in the emergency department setting. OBJECTIVES: To develop and validate a clinical prediction rule for identifying patients with severe community-acquired pneumonia, comparing it with other prognostic rules. METHODS: Data collected from clinical information and physical examination of 1,057 patients visiting the emergency department of a hospital were used to derive a clinical prediction rule, which was then validated in two different populations: 719 patients from the same center and 1,121 patients from four other hospitals. MEASUREMENTS AND MAIN RESULTS: In the multivariate analyses, eight independent predictive factors were correlated with severe community-acquired pneumonia: arterial pH < 7.30, systolic blood pressure < 90 mm Hg, respiratory rate > 30 breaths/min, altered mental status, blood urea nitrogen > 30 mg/dl, oxygen arterial pressure < 54 mm Hg or ratio of arterial oxygen tension to fraction of inspired oxygen < 250 mm Hg, age > or = 80 yr, and multilobar/bilateral lung affectation. From the beta parameter obtained in the multivariate model, a score was assigned to each predictive variable. The model shows an area under the curve of 0.92. This rule proved better at identifying patients evolving toward severe community-acquired pneumonia than either the modified American Thoracic Society rule, the British Thoracic Society's CURB-65, or the Pneumonia Severity Index. CONCLUSIONS: A simple score using clinical data available at the time of the emergency department visit provides a practical diagnostic decision aid, and predicts the development of severe community-acquired pneumonia.  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