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   1228篇
  免费   44篇
  国内免费   3篇
耳鼻咽喉   9篇
儿科学   33篇
妇产科学   34篇
基础医学   195篇
口腔科学   3篇
临床医学   110篇
内科学   307篇
皮肤病学   18篇
神经病学   122篇
特种医学   24篇
外科学   110篇
综合类   5篇
一般理论   3篇
预防医学   134篇
眼科学   13篇
药学   81篇
肿瘤学   74篇
  2024年   3篇
  2023年   9篇
  2022年   8篇
  2021年   33篇
  2020年   9篇
  2019年   11篇
  2018年   36篇
  2017年   12篇
  2016年   12篇
  2015年   16篇
  2014年   27篇
  2013年   46篇
  2012年   79篇
  2011年   91篇
  2010年   45篇
  2009年   50篇
  2008年   111篇
  2007年   118篇
  2006年   79篇
  2005年   102篇
  2004年   91篇
  2003年   78篇
  2002年   78篇
  2001年   12篇
  2000年   3篇
  1999年   10篇
  1998年   14篇
  1997年   13篇
  1996年   16篇
  1995年   12篇
  1994年   6篇
  1993年   7篇
  1992年   6篇
  1991年   1篇
  1990年   5篇
  1989年   1篇
  1988年   2篇
  1987年   3篇
  1986年   1篇
  1985年   1篇
  1984年   3篇
  1983年   2篇
  1982年   2篇
  1981年   3篇
  1980年   1篇
  1979年   3篇
  1977年   1篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
排序方式: 共有1275条查询结果,搜索用时 25 毫秒
41.
42.
43.
44.
45.
The aim of this exploratory study was to evaluate the gut microbial signatures of distinct trimethylamine N-oxide (TMAO) responses following raspberry consumption. Investigations were carried out in 24 subjects at risk of developing metabolic syndrome who received 280 g/day of frozen raspberries for 8 weeks. Blood and stool samples were collected at weeks 0 and 8. Inter-individual variability in plasma TMAO levels was analyzed, 7 subjects were excluded due to noninformative signals and 17 subjects were kept for analysis and further stratified according to their TMAO response. Whole-metagenome shotgun sequencing analysis was used to determine the impact of raspberry consumption on gut microbial composition. Before the intervention, the relative abundance of Actinobacteriota was significantly higher in participants whose TMAO levels increased after the intervention (p = 0.03). The delta TMAO (absolute differences of baseline and week 8 levels) was positively associated with the abundance of gut bacteria such as Bilophila wadsworthia (p = 0.02; r2 = 0.37), from the genus Granulicatella (p = 0.03; r2 = 0.48) or the Erysipelotrichia class (p = 0.03; r2 = 0.45). Changes in the gut microbial ecology induced by raspberry consumption over an 8-week period presumably impacted quaternary amines-utilizing activity and thus plasma TMAO levels.  相似文献   
46.
47.
Several studies have demonstrated that patients with schizophrenia show impairments in social cognition and current evidence indicate that this deficit is associated with abnormal activity in specific brain regions. In addition to functional imaging studies, we believe that the identification of structural correlates of social cognitive processes may help to better understand the neural underpinnings of these specific skills. The main objective of this study was to investigate the relationship between gray matter density and social cognitive deficits in first episode of schizophrenia spectrum psychosis, using a comprehensive assessment that we previously demonstrated to be a highly sensitive measure of social cognitive deficits in this population. Thirty-eight patients with a first episode of psychosis participated in this study, and the Four Factor Test of Social Intelligence was used as a measure of social cognition. Social cognitive impairments in first episode psychosis were significantly correlated with reduced gray-matter density in the left middle frontal gyrus other regions within the mirror neuron system network (MSN), namely the right supplementary motor cortex, the left superior temporal gyrus and the left inferior parietal lobule. We concluded that structural abnormalities within the MSN may account for the social cognitive deficits present in some psychiatric disorders, such as schizophrenia.  相似文献   
48.
49.
50.

Background

Differences in sexual behaviour are partly responsible for significant inequalities in human papillomavirus (HPV)-related diseases between sub-populations. Our aim was to illustrate how differential HPV vaccine uptake by sexual behaviour can impact population-level vaccination effectiveness and inequalities in HPV prevalence.

Methods

We used a multi-type individual-based transmission-dynamic model of HPV infection. The modelled population is stratified into 4 sexual activity levels (low = L0, high = L3). The model was calibrated to Canadian epidemiological data, including the proportion of sexually active individuals by gender and type-specific HPV prevalence by level of sexual activity. Vaccine uptake by sexual activity level was varied in one-way sensitivity analyses. Uncertainty in model predictions is presented using the median [10-90th percentiles] of simulations.

Results

In our pre-vaccination calibrated modelled population, the most sexually active risk groups (L2–L3) account for 43% of prevalent HPV-16/18 infections while only representing 20% of the population. Under base case assumptions (age at vaccination = 12 years, vaccine efficacy = 100%, average duration of protection = 20 years, overall coverage = 50%), vaccinating girls is predicted to reduce HPV-16/18 prevalence by 56% [46–69] at equilibrium (70 years post-vaccination) when uptake is uniform across sexual activity levels, and by 35% [28–40] when uptake is maldistributed (L0: 100%, L1: 55%, L2: 0%, L3: 0%). At uniform 50% vaccination coverage across risk groups, HPV-16/18 prevalence is predicted to be reduced by 62% [52–73], 74% [57–82], 40% [24–60], and 28% [7–54] at equilibrium among women in levels of sexual activity L0, L1, L2 and L3, respectively.

Conclusions

A low vaccine uptake in girls at highest risk of future HPV acquisition may substantially limit population effectiveness of vaccination. Vaccination effectiveness is lower in more sexually active groups due to smaller herd effects. Uniform vaccination coverage across sub-populations may not be able to decrease existing inequalities in HPV infection and disease unless coverage is high enough to produce herd effects in higher risk groups.  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