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   1526篇
  免费   93篇
  国内免费   6篇
耳鼻咽喉   31篇
儿科学   104篇
妇产科学   31篇
基础医学   233篇
口腔科学   20篇
临床医学   114篇
内科学   288篇
皮肤病学   19篇
神经病学   155篇
特种医学   44篇
外科学   154篇
综合类   18篇
一般理论   1篇
预防医学   170篇
眼科学   23篇
药学   128篇
中国医学   3篇
肿瘤学   89篇
  2024年   2篇
  2023年   15篇
  2022年   24篇
  2021年   65篇
  2020年   46篇
  2019年   44篇
  2018年   62篇
  2017年   42篇
  2016年   52篇
  2015年   45篇
  2014年   58篇
  2013年   93篇
  2012年   131篇
  2011年   112篇
  2010年   76篇
  2009年   55篇
  2008年   104篇
  2007年   93篇
  2006年   77篇
  2005年   72篇
  2004年   76篇
  2003年   62篇
  2002年   67篇
  2001年   9篇
  2000年   13篇
  1999年   13篇
  1998年   11篇
  1997年   10篇
  1996年   6篇
  1995年   8篇
  1994年   7篇
  1993年   4篇
  1992年   8篇
  1991年   15篇
  1990年   5篇
  1989年   8篇
  1988年   5篇
  1987年   4篇
  1986年   7篇
  1985年   8篇
  1984年   2篇
  1983年   5篇
  1982年   2篇
  1980年   1篇
  1976年   1篇
排序方式: 共有1625条查询结果,搜索用时 31 毫秒
51.
52.
A 72‐year‐old woman with a history of paroxysmal atrial fibrillation (AF) and sinus node dysfunction is seen in clinic for routine follow‐up.  相似文献   
53.
Inclusion body myositis is a rare sporadic inflammatory‐degenerative myopathy of the elderly. Despite being the commonest type of acquired myopathy after the age of 50, misdiagnosis is extremely common. The most frequent hurdle in identifying new cases is the wrong diagnosis of polymyositis or motor neuron disease. Novel insights into pathogenic mechanisms have heralded the quest for newer therapeutics as well as drug repurposing in this otherwise progressive disorder.  相似文献   
54.
55.
Increased physical activity (PA) is associated with improvement of cardiac risk factors and prevention of cardiovascular disease, yet many women remain sedentary. With rising Internet use, Web-based interventions provide an alternative to improve PA, but their effectiveness for change in PA and quality of life (QOL) in a real-world setting is unknown. Participants were United States women ≥18 years old who received 12 weekly PA modules and completed surveys on PA, QOL, and readiness for PA at registration (registration cohort, n = 3,796) or registration and 12 weeks (evaluation cohort, n = 892). QOL was assessed with a modified Short Form-36 with subscores for energy and well-being. Participants showed significant (p <0.001) favorable changes in PA (baseline, median 240 kcal/week, interquartile range 62 to 667; 12 weeks, 343 kcal/week, 131 to 828), stage of readiness for PA, and body mass index (baseline, 29.3 kg/m(2), 24.9 to 34.7; 12 weeks, 28.9 kg/m(2), 24.6 to 34.2). Significant improvements (p <0.0001) were also found in composite scores for energy and well-being. Compliance with PA guideline recommendations increased from 15.8% to 21.4%. Program weeks completed (p = 0.03), energy (p = 0.04), and well-being (p = 0.002) were significantly associated with achieving guideline compliance. In women reporting no PA at baseline (n = 88), program participation resulted in 54.6% achieving some PA and another 9.1% achieving total compliance with recommendations. In conclusion, in this national cohort of women, a 12-week Web-based intervention improved PA and QOL measurements, resulting in higher short-term PA guideline compliance and better QOL. Increasing use of this simple Web-based tool could improve PA and promote disease prevention.  相似文献   
56.
Inflammaging refers to a low-grade pro-inflammatory phenotype which accompanies aging in mammals. The aging process is associated with a decline in autophagic capacity which impairs cellular housekeeping, leading to protein aggregation and accumulation of dysfunctional mitochondria which provoke reactive oxygen species (ROS) production and oxidative stress. Recent studies have clearly indicated that the ROS production induced by damaged mitochondria can stimulate intracellular danger-sensing multiprotein platforms called inflammasomes. Nod-like receptor 3 (NLRP3) can be activated by many danger signals, e.g. ROS, cathepsin B released from destabilized lysosomes and aggregated proteins, all of which evoke cellular stress and are involved in the aging process. NLRP3 activation is also enhanced in many age-related diseases, e.g. atherosclerosis, obesity and type 2 diabetes. NLRP3 activates inflammatory caspases, mostly caspase-1, which cleave the inactive precursors of IL-1β and IL-18 and stimulate their secretion. Consequently, these cytokines provoke inflammatory responses and accelerate the aging process by inhibiting autophagy. In conclusion, inhibition of autophagic capacity with aging generates the inflammaging condition via the activation of inflammasomes, in particular NLRP3. We will provide here a perspective on the current research of the ROS-dependent activation of inflammasomes triggered by the decline in autophagic cleansing of dysfunctional mitochondria.  相似文献   
57.
Recent studies have shown that a single-nucleotide polymorphism upstream of the interleukin-28B (IL28B) gene plays a major role in predicting therapeutic response in hepatitis C virus (HCV)-infected patients treated with pegylated interferon (PEG-IFN)/ribavirin. We sought to investigate the mechanism of the IL28B polymorphism, specifically as it relates to early HCV viral kinetics, IFN pharmacokinetics, IFN pharmacodynamics, and gene expression profiles. Two prospective cohorts (human immunodeficiency virus [HIV]/HCV-coinfected and HCV-monoinfected) completing treatment with IFN/ribavirin were enrolled. Patients were genotyped at the polymorphic site rs12979860. In the HIV/HCV cohort, frequent serum sampling was completed for HCV RNA and IFN levels. DNA microarray of peripheral blood mononuclear cells and individual expression of IFN-stimulated genes (ISGs) were quantified on IFN therapy. The IL28B-favorable (CC) genotype was associated with improved therapeutic response compared with unfavorable (CT or TT) genotypes. Patients with a favorable genotype had greater first- and second-phase viral kinetics (P = 0.004 and P = 0.036, respectively), IFN maximum antiviral efficiency (P = 0.007) and infected cell death loss (P = 0.009) compared with unfavorable genotypes. Functional annotation analysis of DNA microarray data was consistent with depressed innate immune function, particularly of natural killer cells, from patients with unfavorable genotypes (P <0.004). Induction of innate immunity genes was also lower in unfavorable genotypes. ISG expression at baseline and induction with IFN was independent of IL28B genotype. CONCLUSION: Carriers of the IL28B-favorable genotype were more likely to have superior innate immune response to IFN therapy compared with unfavorable genotypes, suggesting that the unfavorable genotype has aberrant baseline induction of innate immune response pathways resulting in impaired virologic response. IL28B genotype is associated with more rapid viral kinetics and improved treatment response outcomes independent of ISG expression.  相似文献   
58.
An experimental, single-subject research study investigated the comparative efficacy of the Picture Exchange Communication System (PECS) versus a speech-generating device (SGD) in developing requesting skills for three elementary-age children with severe autism and little to no functional speech. Results demonstrated increases in requesting behavior for all participants across intervention phases with both augmentative and alternative communication (AAC) intervention strategies; however, difficulties were observed with picture discrimination. The Wilcoxon signed pair test did not reveal significant differences between PECS and the SGD for any participant. Findings suggest PECS and SGD are equally appropriate for developing initial requesting skills. Based on the current findings, successful implementation of either AAC strategy is achievable when appropriate instructional strategies are used.  相似文献   
59.
60.
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