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   1449篇
  免费   95篇
  国内免费   10篇
耳鼻咽喉   21篇
儿科学   51篇
妇产科学   34篇
基础医学   229篇
口腔科学   82篇
临床医学   161篇
内科学   279篇
皮肤病学   12篇
神经病学   187篇
特种医学   23篇
外科学   88篇
综合类   5篇
预防医学   120篇
眼科学   28篇
药学   76篇
中国医学   5篇
肿瘤学   153篇
  2024年   2篇
  2023年   24篇
  2022年   43篇
  2021年   74篇
  2020年   29篇
  2019年   41篇
  2018年   48篇
  2017年   37篇
  2016年   53篇
  2015年   47篇
  2014年   62篇
  2013年   87篇
  2012年   146篇
  2011年   137篇
  2010年   72篇
  2009年   50篇
  2008年   84篇
  2007年   78篇
  2006年   84篇
  2005年   88篇
  2004年   76篇
  2003年   69篇
  2002年   53篇
  2001年   6篇
  2000年   1篇
  1999年   7篇
  1998年   9篇
  1997年   2篇
  1996年   9篇
  1995年   5篇
  1994年   2篇
  1993年   1篇
  1992年   1篇
  1990年   2篇
  1989年   1篇
  1987年   1篇
  1986年   3篇
  1985年   1篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1977年   2篇
  1976年   3篇
  1975年   4篇
  1973年   1篇
  1971年   1篇
  1970年   1篇
  1944年   1篇
  1942年   1篇
排序方式: 共有1554条查询结果,搜索用时 15 毫秒
21.

BACKGROUND

Little is known about how providers communicate recommendations when scientific uncertainty exists.

OBJECTIVES

To compare provider recommendations to those in the scientific literature, with a focus on whether uncertainty was communicated.

DESIGN

Qualitative (inductive systematic content analysis) and quantitative analysis of previously collected audio-recorded provider–patient office visits.

PARTICIPANTS

Sixty-one providers and a socio-economically diverse convenience sample of 603 of their patients from outpatient community- and academic-based primary care, integrative medicine, and complementary and alternative medicine provider offices in Southern California.

MAIN MEASURES

Comparison of provider information-giving about vitamin D to professional guidelines and scientific information for which conflicting recommendations or insufficient scientific evidence exists; certainty with which information was conveyed.

RESULTS

Ninety-two (15.3 %) of 603 visit discussions touched upon issues related to vitamin D testing, management and benefits. Vitamin D deficiency screening was discussed with 23 (25 %) patients, the definition of vitamin D deficiency with 21 (22.8 %), the optimal range for vitamin D levels with 26 (28.3 %), vitamin D supplementation dosing with 50 (54.3 %), and benefits of supplementation with 46 (50 %). For each of the professional guidelines/scientific information examined, providers conveyed information that deviated from professional guidelines and the existing scientific evidence. Of 166 statements made about vitamin D in this study, providers conveyed 160 (96.4 %) with certainty, without mention of any equivocal or contradictory evidence in the scientific literature. No uncertainty was mentioned when vitamin D dosing was discussed, even when recommended dosing was higher than guideline recommendations.

CONCLUSIONS AND RELEVANCE

Providers convey the vast majority of information and recommendations about vitamin D with certainty, even though the scientific literature contains inconsistent recommendations and declarations of inadequate evidence. Not communicating uncertainty blurs the contrast between evidence-based recommendations and those without evidence. Providers should explore best practices for involving patients in decision-making by acknowledging the uncertainty behind their recommendations.
  相似文献   
22.
We present the nature of pathogenic SNP array findings in pregnancies without ultrasound (US) abnormalities and show the additional diagnostic value of SNP array as compared with rapid aneuploidy detection and karyotyping. 1,330 prenatal samples were investigated with a 0.5‐Mb SNP array after the exclusion of the most common aneuploidies. In 2.7% (36/1,330) of the cases, pathogenic chromosome aberrations were found; a microscopically detectable abnormality in 0.7% and a submicroscopic aberration in 2%. Our results show that in addition to the age‐ or screening‐related aneuploidy risk, in pregnancies without US abnormalities, there is a risk of 1:148 (9/1,330) for a (sub)microscopic abnormality associated with an early‐onset often severe disease, 1:222 (6/1,330) for a submicroscopic aberration causing an early‐onset disease, 1:74 (18/1,330) for carrying a susceptibility locus for a neurodevelopmental disorder, and 1:443 (3/1,330) for a late‐onset disorder (hereditary neuropathy with liability to pressure palsies in all three cases). These risk figures are important for adequate pretest counseling so that prospective parents can make informed individualized choices between targeted prenatal testing and broad testing with SNP array. Based on our results, we believe if invasive testing is performed, SNP array should be the preferred cytogenetic technique irrespective of the indication.  相似文献   
23.
24.
Limited data are available on the longitudinal occurrence of syndemic factors among women at risk for HIV infection in the USA and how these factors relate to sexual risk over time. HVTN 906 was a longitudinal study enrolling 799 HIV-uninfected women in three cities. Assessments were done at baseline, 6, 12, and 18 months to assess syndemic factors (low education, low income, unemployment, lack of health insurance, housing instability, substance use, heavy alcohol use, partner violence, incarceration) and sexual risk outcomes. For each sexual risk outcome, a GEE model was fit with syndemic factors or syndemic score (defined as sum of binary syndemics, ranging from 0 to 9), visit, study site, age and race/ethnicity as predictors to examine the multivariable association between syndemic factors and outcomes over time. Odds of unprotected sex while drunk or high were significantly higher when women reported lack of health insurance, substance and heavy alcohol use and partner violence. Housing instability, substance and heavy alcohol use, partner violence and recent incarceration were associated with higher odds of having multiple sexual partners. Odds of sex exchange were significantly higher in the presence of unemployment, housing instability, low education, lack of health insurance, substance and heavy alcohol use, partner violence and incarceration. Housing instability, substance and heavy alcohol use, and partner violence were significantly associated with higher odds of unprotected anal sex. Odds of having a recent STI were significantly higher when women reported housing instability and partner violence. There were significantly higher odds of the reporting of any risk outcomes during follow-up with higher syndemic score. This study highlights a group of women experiencing multiple poor social and health outcomes who need to be the focus of comprehensive interventions.  相似文献   
25.
26.
International Journal of Legal Medicine - A correct assessment on the position, path, and direction of fracture lines is crucial when the sequence of different injuries on the skull has to be...  相似文献   
27.
International Journal of Legal Medicine - Human decomposition in sea water poses several challenges to forensic practitioners tasked with the analysis of drowned bodies. Postmortem changes in the...  相似文献   
28.

Background

The Temperament Evaluation of Memphis, Pisa, Paris and San Diego – Autoquestionnaire (TEMPS-A) is a widely used self-reported tool aimed at measuring the affective temperaments that define the bipolar spectrum, with cyclothymic, depressive, irritable, hyperthymic, and anxious subscales. Confirmatory factor analysis (CFA) was rarely used to confirm the expected five-factor model. Measurement invariance was never tested.

Methods

Cross-sectional, survey design involving 649 Italian college students (males: 47%). The short 39-item TEMPS-A and the 12-item General Health Questionnaire (GHQ-12) were used as measures of the affective temperaments and of psychological distress, respectively. CFA was applied to the TEMPS-A. Measurement invariance by gender, age and levels of psychological distress on the GHQ-12 was calculated with the establishment of subsequent equivalence constraints in the model parameters across groups.

Results

The expected five-factor model had the best fit for all CFA indexes. Configural, metric and scalar invariance of the five-factor model of the TEMPS-A was proved across gender, age and levels of psychological distress of the participants. The hyperthymic temperament subscale has low or no links with the other affective temperament subscales, which were interrelated with medium to large effect sizes.

Limitations

College students might be not representative of the general population. No information on the clinical status of the students was available beyond self-report data.

Conclusion

The study proved the measurement invariance of the (short) TEMPS-A, which is a pre-requisite to compare groups or individuals in cross-sectional and longitudinal surveys. Generalizability cannot be assumed without replication of the findings in clinical samples.  相似文献   
29.
30.
Ouarhache  Maryem  Marquet  Sandrine  Frade  Amanda Farage  Ferreira  Ariela Mota  Ianni  Barbara  Almeida  Rafael Ribeiro  Nunes  Joao Paulo Silva  Ferreira  Ludmila Rodrigues Pinto  Rigaud  Vagner Oliveira-Carvalho  Cândido  Darlan  Mady  Charles  Zaniratto  Ricardo Costa Fernandes  Buck  Paula  Torres  Magali  Gallardo  Frederic  Andrieux  Pauline  Bydlowsky  Sergio  Levy  Debora  Abel  Laurent  Cardoso  Clareci Silva  Santos-Junior  Omar Ribeiro  Oliveira  Lea Campos  Oliveira  Claudia Di Lorenzo  Nunes  Maria Do Carmo  Cobat  Aurelie  Kalil  Jorge  Ribeiro  Antonio Luiz  Sabino  Ester Cerdeira  Cunha-Neto  Edecio  Chevillard  Christophe 《Journal of clinical immunology》2021,41(5):1048-1063
Abstract

Cardiomyopathies are an important cause of heart failure and sudden cardiac death. Little is known about the role of rare genetic variants in inflammatory cardiomyopathy. Chronic Chagas disease cardiomyopathy (CCC) is an inflammatory cardiomyopathy prevalent in Latin America, developing in 30% of the 6 million patients chronically infected by the protozoan Trypanosoma cruzi, while 60% remain free of heart disease (asymptomatic (ASY)). The cytokine interferon-γ and mitochondrial dysfunction are known to play a major pathogenetic role. Chagas disease provides a unique model to probe for genetic variants involved in inflammatory cardiomyopathy.

Methods

We used whole exome sequencing to study nuclear families containing multiple cases of Chagas disease. We searched for rare pathogenic variants shared by all family members with CCC but absent in infected ASY siblings and in unrelated ASY.

Results

We identified heterozygous, pathogenic variants linked to CCC in all tested families on 22 distinct genes, from which 20 were mitochondrial or inflammation-related – most of the latter involved in proinflammatory cytokine production. Significantly, incubation with IFN-γ on a human cardiomyocyte line treated with an inhibitor of dihydroorotate dehydrogenase brequinar (enzyme showing a loss-of-function variant in one family) markedly reduced mitochondrial membrane potential (ΔψM), indicating mitochondrial dysfunction.

Conclusion

Mitochondrial dysfunction and inflammation may be genetically determined in CCC, driven by rare genetic variants. We hypothesize that CCC-linked genetic variants increase mitochondrial susceptibility to IFN-γ-induced damage in the myocardium, leading to the cardiomyopathy phenotype in Chagas disease. This mechanism may also be operative in other inflammatory cardiomyopathies.

  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