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   159篇
  免费   36篇
  国内免费   1篇
耳鼻咽喉   1篇
妇产科学   2篇
基础医学   13篇
口腔科学   1篇
临床医学   12篇
内科学   36篇
皮肤病学   3篇
神经病学   13篇
特种医学   19篇
外科学   8篇
综合类   9篇
预防医学   51篇
眼科学   7篇
  1篇
中国医学   2篇
肿瘤学   18篇
  2024年   4篇
  2023年   19篇
  2022年   27篇
  2021年   32篇
  2020年   16篇
  2019年   15篇
  2018年   17篇
  2017年   6篇
  2016年   10篇
  2015年   9篇
  2014年   15篇
  2013年   5篇
  2012年   7篇
  2011年   2篇
  2010年   1篇
  2009年   3篇
  2008年   5篇
  2007年   1篇
  2006年   2篇
排序方式: 共有196条查询结果,搜索用时 15 毫秒
1.
Recent epidemiological studies suggested that proton pump inhibitor (PPI) use was associated with an increased risk of biliary tract cancer (BTC), however, confounders were not adequately controlled. Our study aimed to evaluate PPI use and subsequent risk of BTC and its subtypes in three well-established cohorts. We conducted a pooled analysis of the subjects free of cancers in UK Biobank (n = 463 643), Nurses' Health Study (NHS, n = 80 235) and NHS II (n = 95 869). Propensity score weighted Cox models were used to estimate marginal HRs of PPIs use on BTC risk, accounting for potential confounders. We documented 284 BTC cases in UK Biobank (median follow-up: 7.6 years), and 91 cases in NHS and NHS II cohorts (median follow-up: 15.8 years). In UK biobank, PPI users had a 96% higher risk of BTC compared to nonusers in crude model (HR 1.96, 95% CI 1.44-2.66), but the effect was attenuated to null after adjusting for potential confounders (HR 0.95, 95% CI 0.60-1.49). PPI use was not associated with risk of BTC in the pooled analysis of three cohorts (HR 0.93, 95% CI 0.60-1.43). We also observed no associations between PPI use with risk of intrahepatic (HR 1.00, 95% CI 0.49-2.04), extrahepatic bile duct (HR 1.09, 95% CI 0.52-2.27) and gallbladder cancers (HR 0.66, 95% CI 0.26-1.66) in UK Biobank. In summary, regular use of PPIs was not associated with the risk of BTC and its subtypes.  相似文献   
2.
Loss of function variants in NOTCH1 cause left ventricular outflow tract obstructive defects (LVOTO). However, the risk conferred by rare and noncoding variants in NOTCH1 for LVOTO remains largely uncharacterized. In a cohort of 49 families affected by hypoplastic left heart syndrome, a severe form of LVOTO, we discovered predicted loss of function NOTCH1 variants in 6% of individuals. Rare or low-frequency missense variants were found in 16% of families. To make a quantitative estimate of the genetic risk posed by variants in NOTCH1 for LVOTO, we studied associations of 400 coding and noncoding variants in NOTCH1 in 1,085 cases and 332,788 controls from the UK Biobank. Two rare intronic variants in strong linkage disequilibrium displayed significant association with risk for LVOTO amongst European-ancestry individuals. This result was replicated in an independent analysis of 210 cases and 68,762 controls of non-European and mixed ancestry. In conclusion, carrying rare predicted loss of function variants in NOTCH1 confer significant risk for LVOTO. In addition, the two intronic variants seem to be associated with an increased risk for these defects. Our approach demonstrates the utility of population-based data sets in quantifying the specific risk of individual variants for disease-related phenotypes.  相似文献   
3.
The relationship between depression and vitamin D deficiency is complex, with evidence mostly from studies affected by confounding and reverse causality. We examined the causality and direction of the relationship between 25-hydroxyvitamin D (25(OH)D) and depression in bi-directional Mendelian randomization (MR) analyses using information from up to 307,618 white British participants from the UK Biobank and summary results from the SUNLIGHT (n = 79,366) and Psychiatric Genomics consortia (PGC 113,154 cases and 218,523 controls). In observational analysis, the odds of depression decreased with higher 25(OH)D concentrations (adjusted odds ratio (OR) per 50% increase 0.95, 95%CI 0.94–0.96). In MR inverse variance weighted (IVW) using the UK Biobank, there was no association between genetically determined serum 25(OH)D and depression (OR per 50% higher 0.97, 95%CI 0.90–1.05) with consistent null association across all MR approaches and in data from PGC consortium. In contrast, genetic liability to depression was associated with lower 25(OH)D concentrations (MR IVW −3.26%, −4.94%–−1.55%), with the estimates remaining generally consistent after meta-analysing with the consortia. In conclusion, we found genetic evidence for a causal effect of depression on lower 25(OH)D concentrations, however we could not confirm a beneficial effect of nutritional vitamin D status on depression risk.  相似文献   
4.
Background and aimThe present study was conducted to explore the stratified and joint effects of age at menopause and body mass index (BMI) with the risk of type 2 diabetes mellitus (T2DM) in Chinese rural adults.Methods and resultsA total of 15,406 postmenopausal Chinese women were included in this study. Multivariable logistic regression analysis was used to quantify the stratified and joint effects of age at menopause and BMI on T2DM. Overall, the mean age at menopause and BMI was 48.8 ± 4.7 years and 25.1 ± 3.6 kg/m2, respectively. In general, data suggest that: 1) women with BMI ≥ 24 had a higher risk of T2DM, irrespective of age at menopause; 2) in women with BMI < 24, later menopause had a higher risk of T2DM (OR, 1.52; 95% CI, 1.16–2.01); 3) the risk of T2DM was higher only in patients with early or normal age at menopause and BMI ≥ 24, with 0R (95% CI) of (1.58, 1.28–1.94) and (1.48, 1.31–1.67), respectively.ConclusionOur findings suggest that: 1) women with BMI ≥ 24 had a higher risk of T2DM, irrespective of age at menopause; 2) in women with BMI < 24, a higher risk of T2DM was found only in those with later menopause; 3) women with later menopause had a higher risk of T2DM, irrespective of BMI; 4) in patients with early or normal age at menopause, a higher risk of T2DM was found only in patients with BMI ≥ 24.The Chinese Clinical Trial RegistrationChiCTR–OOC–1500669(URL:http://www.chictr.org.cn/showproj.aspx?proj=11375)  相似文献   
5.
Genetic and hormonal factors have been suggested to influence human sexual orientation. Previous studied proposed brain differences related to sexual orientation and that these follow cross‐sex shifted patterns. However, the neurobiological correlates of sexual orientation and how genetic factors relate to brain structural variation remains largely unexplored. Using the largest neuroimaging‐genetics dataset available on same‐sex sexual behavior (SSB) (n = 18,645), we employed a data‐driven multivariate classification algorithm (PLS) on magnetic resonance imaging data from two imaging modalities to extract brain covariance patterns related to sex. Through analyses of latent variables, we tested for SSB‐related cross‐sex shifts in such patterns. Using genotype data, polygenic scores reflecting the genetic predisposition for SSB were computed and tested for associations with neuroimaging outcomes. Patterns important for classifying between males and females were less pronounced in non‐heterosexuals. Predominantly in non‐heterosexual females, multivariate brain patterns as represented by latent variables were shifted toward the opposite sex. Complementary univariate analyses revealed region specific SSB‐related differences in both males and females. Polygenic scores for SSB were associated with volume of lateral occipital and temporo‐occipital cortices. The present large‐scale study demonstrates multivariate neuroanatomical correlates of SSB, and tentatively suggests that genetic factors related to SSB may contribute to structural variation in certain brain structures. These findings support a neurobiological basis to the differences in human sexuality.  相似文献   
6.
BackgroundLow fat-free mass (FFM) is a risk factor for morbidity and mortality in elderly and patient populations. Therefore, measurement of FFM is important in nutritional assessment. Bioelectrical impedance analysis (BIA) is a convenient method to assess FFM and FFM index (FFMI; FFM/height2). Although reference values have been established for individuals with normal body weight, no specific cutoff values are available for overweight and obese populations. Also, limited studies accounted for the age-related decline in FFM.ObjectiveTo determine BMI- and age-specific reference values for abnormal low FFM(I) in white-ethnic men and women free of self-reported disease from the general population.DesignThe UK Biobank is a prospective epidemiological study of the general population from the United Kingdom. Individuals in the age category 45 to 69 years were analyzed. In addition to body weight, FFM and FFMI were measured using a Tanita BC-418MA. Also, self-reported chronic conditions and ethnic background were registered, and lung function was assessed using spirometry.ResultsAfter exclusion of all individuals with missing data, nonwhite ethnicity, self-reported disease, body mass index (BMI) less than 14 or 36 kg/m2 or higher, and/or an obstructive lung function, reference values for FFM and FFMI were derived from 186,975 individuals (45.9% men; age: 56.9 ± 6.8 years; BMI: 26.5 ± 3.6 kg/m2; FFMI 18.3 ± 2.4 kg/m2). FFM and FFMI were significantly associated with BMI and decreased with age. Percentiles 5, 10, 25, 50, 75, 90, and 95 were calculated for FFM, FFMI, and fat mass (index), after stratification for gender, age, and BMI.ConclusionsUsing the UK Biobank dataset, new reference values for body composition assessed with BIA were determined in white-ethnic men and women aged 45 to 69 years. Because these reference values are BMI specific, they are of broad interest for overweight and obese populations.  相似文献   
7.
生物样本库作为临床治疗和医学科学研究的基础设施,是推动临床医学学科创新与诊疗技术创新的关键。目前我国生物样本库行业处于加速发展阶段,但存在缺乏统一的标准化流程,生物样本学科尚未建成、缺乏专业的人才队伍、各个样本库之间相互独立缺乏资源共享机制、样本库的成本效益低,样本使用率低等问题。针对上述问题,应加强生物样本库标准化建设,建立生物样本学,培养高素质专业人才,整合样本资源,实现信息共享,提高样本使用率,促进可持续发展。  相似文献   
8.
目的 探讨在非溶血和溶血状态下,低温保藏时间对结直肠癌患者血浆miRNA标志物质量的影响。方法 随机抽取中山大学附属第三医院生物样本资源库2014年至2021年间在-80℃低温环境下保藏不同时间的结直肠癌血浆标本,采用分光光度计检测评估血浆溶血程度,并分为溶血组和非溶血组。miRNA提取后采用实时荧光定量PCR对潜在的结直肠癌miRNA标志物miR-92a-3p和miR-378a-5p进行丰度分析和比较。结果 在-80℃低温储存环境下,非溶血组保藏8年以及溶血组保藏3年的血浆中miR-92a-3p和miR-378a-5p丰度无明显变化,溶血组保藏1、3年的血浆中miR-92a-3p的丰度显著高于同期非溶血组(均P<0.01),而两组同期保藏1、3年miR-378a-5p的丰度差异无统计学意义(P=0.931、0.339)。结论 血浆初始溶血状态会影响循环miRNA的丰度,但低温保藏时间不影响血浆中miRNA的丰度,能较好地保持血浆样本中miRNA的稳定,用于后续研究。  相似文献   
9.
随着精准医疗和转化医学的发展进步,生物样本库作为链接临床工作和实验室研究的重要环节,在国内外医学研究领域越来越受到重视。本文从生物样本库的国内外发展现状、特勤人员生物样本库建设要点、建设特勤人员生物样本库的意义这三个方面进行阐述,分析探讨建设特勤人员生物样本库的重要性,加强未来对特勤人员的精准化、个性化医疗保障工作。  相似文献   
10.
目的 开发适合我国脑血管病精准医学研究的生物样本库建设及管理标准,为建设可开发共享的脑血管病生物样本库提供技术保障.方法 参考国际大型生物样本库建设经验,基于国际标准化组织等机构的标准化思路,形成我国脑血管病生物样本库建设标准框架,从场地设施、设备、操作规程、数据标准、信息化等多个维度,对样本库的建设提出技术要求.结果...  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