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   1879篇
  免费   126篇
  国内免费   16篇
耳鼻咽喉   25篇
儿科学   51篇
妇产科学   51篇
基础医学   230篇
口腔科学   51篇
临床医学   117篇
内科学   491篇
皮肤病学   36篇
神经病学   182篇
特种医学   16篇
外科学   333篇
综合类   12篇
预防医学   134篇
眼科学   27篇
药学   121篇
中国医学   22篇
肿瘤学   122篇
  2023年   10篇
  2022年   15篇
  2021年   39篇
  2020年   32篇
  2019年   39篇
  2018年   61篇
  2017年   34篇
  2016年   48篇
  2015年   64篇
  2014年   82篇
  2013年   85篇
  2012年   131篇
  2011年   154篇
  2010年   98篇
  2009年   83篇
  2008年   122篇
  2007年   157篇
  2006年   118篇
  2005年   114篇
  2004年   134篇
  2003年   105篇
  2002年   99篇
  2001年   11篇
  2000年   9篇
  1999年   16篇
  1998年   17篇
  1997年   9篇
  1996年   6篇
  1995年   17篇
  1994年   8篇
  1993年   4篇
  1991年   5篇
  1989年   4篇
  1988年   3篇
  1986年   5篇
  1985年   3篇
  1984年   5篇
  1983年   5篇
  1982年   3篇
  1981年   5篇
  1979年   7篇
  1978年   6篇
  1977年   6篇
  1976年   3篇
  1975年   6篇
  1974年   4篇
  1972年   3篇
  1963年   4篇
  1962年   3篇
  1958年   3篇
排序方式: 共有2021条查询结果,搜索用时 15 毫秒
1.
2.
Recent frameworks in cognitive neuroscience and behavioral neurology underscore interoceptive priors as core modulators of negative emotions. However, the field lacks experimental designs manipulating the priming of emotions via interoception and exploring their multimodal signatures in neurodegenerative models. Here, we designed a novel task that involves interoceptive and control-exteroceptive priming conditions followed by post-interoception and post-exteroception facial emotion recognition (FER). We recruited 114 participants, including healthy controls (HCs) as well as patients with behavioral variant frontotemporal dementia (bvFTD), Parkinson''s disease (PD), and Alzheimer''s disease (AD). We measured online EEG modulations of the heart-evoked potential (HEP), and associations with both brain structural and resting-state functional connectivity patterns. Behaviorally, post-interoception negative FER was enhanced in HCs but selectively disrupted in bvFTD and PD, with AD presenting generalized disruptions across emotion types. Only bvFTD presented impaired interoceptive accuracy. Increased HEP modulations during post-interoception negative FER was observed in HCs and AD, but not in bvFTD or PD patients. Across all groups, post-interoception negative FER correlated with the volume of the insula and the ACC. Also, negative FER was associated with functional connectivity along the (a) salience network in the post-interoception condition, and along the (b) executive network in the post-exteroception condition. These patterns were selectively disrupted in bvFTD (a) and PD (b), respectively. Our approach underscores the multidimensional impact of interoception on emotion, while revealing a specific pathophysiological marker of bvFTD. These findings inform a promising theoretical and clinical agenda in the fields of nteroception, emotion, allostasis, and neurodegeneration.SIGNIFICANCE STATEMENT We examined whether and how emotions are primed by interoceptive states combining multimodal measures in healthy controls and neurodegenerative models. In controls, negative emotion recognition and ongoing HEP modulations were increased after interoception. These patterns were selectively disrupted in patients with atrophy across key interoceptive-emotional regions (e.g., the insula and the cingulate in frontotemporal dementia, frontostriatal networks in Parkinson''s disease), whereas persons with Alzheimer''s disease presented generalized emotional processing abnormalities with preserved interoceptive mechanisms. The integration of both domains was associated with the volume and connectivity (salience network) of canonical interoceptive-emotional hubs, critically involving the insula and the anterior cingulate. Our study reveals multimodal markers of interoceptive-emotional priming, laying the groundwork for new agendas in cognitive neuroscience and behavioral neurology.  相似文献   
3.
ABSTRACT

Objective: To examine the relationship between race and smoking behaviors among Latinos/Hispanics.

Design: Using data from the National Adult Tobacco Survey (NATS), we implemented Log-Poisson regression models for each dependent variable (smoking pattern and menthol cigarette use). Each analysis adjusted for age, gender, marital status, employment status, and socioeconomic status (SES). Final pooled cross-sectional sample included 505 Black-Latinos and 9078 White-Latinos.

Results: While no racial differences were found in lifetime smoking status among Latinos, Black-Latinos had a 16.6% (95% CI: 0.274, 0.057) increased risk of menthol smoking compared to White-Latinos.

Conclusions: The results indicate that menthol consumption is influenced by race among Hispanics/Latinos. To comprehensively address racial disparities among Latinos/Hispanics, further attention needs to be given to racial differences in smoking-related risks among Latinos/Hispanics.  相似文献   
4.
5.
6.
7.
Hip fracture rates in Norway rank among the highest in the world, more than double that of Spanish women. Previous studies were unable to demonstrate significant differences between the two populations with respect to bone mass or calcium metabolism. In order to test whether the difference in fracture propensity between both populations could be explained by differences in bone material quality we assessed bone material strength using microindentation in 42 Norwegian and 46 Spanish women with normal BMD values, without clinical or morphometric vertebral fractures, no clinical or laboratory signs of secondary osteoporosis, and without use of drugs with known influence on bone metabolism. Bone material properties were assessed by microindentation of the thick cortex of the mid tibia following local anesthesia of the area using the Osteoprobe device (Active Life Scientific, Santa Barbara, CA, USA). Indentation distance was standardized against a calibration phantom of methylmethacrylate and results, as percentage of this reference value, expressed as bone material strength index units (BMSi). We found that the bone material properties reflected in the BMSi value of Norwegian women was significantly inferior when compared to Spanish women (77 ± 7.1 versus 80.7 ± 7.8, p < 0.001). Total hip BMD was significantly higher in Norwegian women (1.218 g/cm2 versus 0.938 g/cm2, p < 0.001) but regression analysis revealed that indentation values did not vary with BMD r2 = 0.03 or age r2 = 0.04. In conclusion Norwegian women show impaired bone material properties, higher bone mass, and were taller than Spanish women. The increased height will increase the impact on bone after falls, and impaired bone material properties may further enhance the risk fracture after such falls. These ethnic differences in bone material properties may partly explain the higher propensity for fracture in Norwegian women. © 2015 American Society for Bone and Mineral Research.  相似文献   
8.
Glucocorticoids, widely used in inflammatory disorders, rapidly increase bone fragility and, therefore, fracture risk. However, common bone densitometry measurements are not sensitive enough to detect these changes. Moreover, densitometry only partially recognizes treatment‐induced fracture reductions in osteoporosis. Here, we tested whether the reference point indentation technique could detect bone tissue property changes early after glucocorticoid treatment initiation. After initial laboratory and bone density measurements, patients were allocated into groups receiving calcium + vitamin D (Ca+D) supplements or anti‐osteoporotic drugs (risedronate, denosumab, teriparatide). Reference point indentation was performed on the cortical bone layer of the tibia by a handheld device measuring bone material strength index (BMSi). Bone mineral density was measured by dual‐energy X‐ray absorptiometry (DXA). Although Ca+D‐treated patients exhibited substantial and significant deterioration, risedronate‐treated patients exhibited no significant change, and both denosumab‐ and teriparatide‐treated participants exhibited significantly improved BMSi 7 weeks after initial treatment compared with baseline; these trends remained stable for 20 weeks. In contrast, no densitometry changes were observed during this study period. In conclusion, our study is the first to our knowledge to demonstrate that reference point indentation is sensitive enough to reflect changes in cortical bone indentation after treatment with osteoporosis therapies in patients newly exposed to glucocorticoids. © 2015 American Society for Bone and Mineral Research.  相似文献   
9.
BACKGROUND: Actinobacillus actinomycetemcomitans is considered a major etiologic agent of aggressive periodontitis (AgP). Other periodontopathic bacteria such as Porphyromonas gingivalis are also suspected of participating in aggressive periodontitis although the evidence to support this is controversial. The aim of the present study was to determine the prevalence of eight periodontopathic bacteria in Chilean patients with AgP. METHODS: Subgingival plaque samples were collected from 36 aggressive, 30 localized, and six generalized periodontitis patients. Samples from 17 advanced chronic periodontitis (CP) patients were taken as controls. Samples collected from the four deepest periodontal pockets in each patient were pooled in prereduced transport fluid (RTF) and cultured. Periodontal bacteria were primarily identified by colony morphology under stereoscopic microscope and rapid biochemical tests. The identity of some bacterial isolates was confirmed by colony polymerase chain reaction (PCR). RESULTS: AgP showed a significatively higher prevalence of C. rectus than CP (P = 0.036). The only statistical difference found was for C. rectus. Patients with AgP showed a higher, but not statistically significant, prevalence of P. gingivalis, E. corrodens, P. micros, and Capnocytophaga sp. A similar prevalence in both groups of patients was observed for F. nucleatum and P. intermedia/nigrescens, and A. actinomycetemcomitans was less prevalent in AgP than CP patients. In localized AgP, P. intermedia/nigrescens, E. corrodens, F. nucleatum, and P. micros were the more prevalent pathogens in contrast to generalized AgP patients who harbored A. actinomycetemcomitans, P. gingivalis, and Capnocytophaga sp. as the most prevalent bacteria. CONCLUSIONS: C. rectus, P. gingivalis, E. corrodens, P. micros, and Capnocytophaga sp. were the most predominant periodontopathic bacteria of AgP in this Chilean population, but the only statistical difference found here between AgP and CP was for C. rectus, suggesting that the differences in clinical appearance may be caused by factors other than the microbiological composition of the subgingival plaque of these patients. In this study, the prevalence of A. actinomycetemcomitans was much lower than that of P. gingivalis.  相似文献   
10.
World Journal of Surgery - The goal of our study was to evaluate the differences in care and clinical outcomes of patients with chest trauma between two hospitals, including one public trauma...  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