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   63430篇
  免费   5009篇
  国内免费   2189篇
耳鼻咽喉   483篇
儿科学   1334篇
妇产科学   2321篇
基础医学   6999篇
口腔科学   1403篇
临床医学   5474篇
内科学   7261篇
皮肤病学   859篇
神经病学   4146篇
特种医学   1815篇
外国民族医学   9篇
外科学   4797篇
综合类   9571篇
现状与发展   14篇
一般理论   9篇
预防医学   6667篇
眼科学   1777篇
药学   7540篇
  78篇
中国医学   4979篇
肿瘤学   3092篇
  2023年   944篇
  2022年   1263篇
  2021年   2327篇
  2020年   2325篇
  2019年   2861篇
  2018年   2529篇
  2017年   2257篇
  2016年   2051篇
  2015年   2049篇
  2014年   3686篇
  2013年   4873篇
  2012年   3594篇
  2011年   4059篇
  2010年   3205篇
  2009年   2959篇
  2008年   2834篇
  2007年   2824篇
  2006年   2510篇
  2005年   2251篇
  2004年   1895篇
  2003年   1872篇
  2002年   1417篇
  2001年   1347篇
  2000年   1094篇
  1999年   1012篇
  1998年   766篇
  1997年   745篇
  1996年   710篇
  1995年   855篇
  1994年   705篇
  1993年   572篇
  1992年   525篇
  1991年   474篇
  1990年   484篇
  1989年   419篇
  1988年   317篇
  1987年   277篇
  1986年   332篇
  1985年   459篇
  1984年   438篇
  1983年   269篇
  1982年   342篇
  1981年   278篇
  1980年   295篇
  1979年   212篇
  1978年   178篇
  1977年   168篇
  1976年   156篇
  1975年   112篇
  1974年   92篇
排序方式: 共有10000条查询结果,搜索用时 180 毫秒
101.
目的探讨阿奇霉素序贯给药辅助治疗小儿大叶性肺炎的效果及对患儿血清炎症因子水平的影响。方法回顾性分析我院2014年10月至2019年10月收治的120例大叶性肺炎患儿的临床资料,根据治疗方式的不同将其分为对照组(60例,阿奇霉素静脉滴注治疗)和观察组(60例,阿奇霉素序贯给药治疗)。比较两组的治疗效果、不良反应情况、血清炎症因子及肺功能指标水平。结果观察组的治疗总有效率显著高于对照组,不良反应总发生率显著低于对照组(P<0.05)。治疗后,两组的TNF-α、PCT、IFN-γ、TM水平均降低,FVC、TLC、Cdyn水平均升高,且观察组显著优于对照组(P<0.05)。结论阿奇霉素序贯给药辅助治疗小儿大叶性肺炎的效果显著,可有效改善患儿血清炎症因子水平和肺功能指标水平,降低不良反应发生率,值得临床推广应用。  相似文献   
102.
103.
《Clinical neurophysiology》2021,132(2):315-322
ObjectivePrevious studies have demonstrated voluntary movement alterations as well as motor cortex excitability and plasticity changes in patients with mild cognitive impairment (MCI). To investigate the pathophysiology of movement abnormalities in MCI, we tested possible relationships between movement abnormalities and primary motor cortex alterations in patients.MethodsFourteen amnestic MCI (aMCI) patients and 16 healthy controls were studied. Cognitive assessment was performed using clinical scales. Finger tapping was recorded by a motion analysis system. Transcranial magnetic stimulation was used to test the input/output curve of motor evoked potentials, intracortical inhibition, and short-latency afferent inhibition. Primary motor cortex plasticity was probed by theta burst stimulation. We investigated correlations between movement abnormalities, clinical scores, and cortical neurophysiological parameters.ResultsMCI patients showed less rhythmic movement but no other movement abnormalities. Cortical excitability measures were normal in patients, whereas plasticity was reduced. Movement rhythm abnormalities correlated with frontal dysfunction scores.ConclusionOur study in MCI patients demonstrated abnormal voluntary movement and plasticity changes, with no correlation between the two. Altered rhythm correlated with frontal dysfunction.SignificanceOur results contribute to the understanding of pathophysiological mechanisms of motor impairment in MCI.  相似文献   
104.
105.
106.
107.
Objectives: To compare indicators relating to aging and health among veterans and non-veterans, and identify factors associated with subjective wellbeing (SWB) of older New Zealand veterans.

Methods: Self-reported data were obtained from participants in a longitudinal cohort study of New Zealand older adults. Responses from 352 veterans and 1500 non-veterans (age range of 55–86 and gender matched) were selected as a comparison group on indicators related to health and aging. The association of these indicators with veterans’ SWB were assessed using hierarchical regression.

Results: Apart from being older, smoking more, and having more chronic conditions, veterans did not differ from non-veterans on indicators of health and wellbeing. Mental health, physical health, purpose in life, housing satisfaction, and capabilities (choice and freedom) accounted for a significant amount of variance in veterans’ SWB.

Conclusion: Our results suggest that older veterans do not differ greatly on indices of health and aging from their non-veteran peers. Results support previous findings that lower mental and physical health is associated with lower SWB for veterans. Building upon prior findings, the current results demonstrate that interventions focusing on enhancing a sense of purpose in life, supporting one's capability to achieve, and strengthening social and physical environment through social connectedness, may serve as protective factors for SWB in veterans.  相似文献   

108.
109.

Background

Resistin is an immunometabolic mediator that is elevated in several inflammatory disorders. A ligand for Toll-like receptor 4, resistin modulates the recruitment and activation of myeloid cells, notably neutrophils. Neutrophils are major drivers of cystic fibrosis (CF) lung disease, in part due to the release of human neutrophil elastase- and myeloperoxidase-rich primary granules, leading to tissue damage. Here we assessed the relationship of resistin to CF lung disease.

Methods

Resistin levels were measured in plasma and sputum from three retrospective CF cohorts spanning a wide range of disease. We also assessed the ability of neutrophils to secrete resistin upon activation in vitro. Finally, we constructed a multivariate model assessing the relationship between resistin levels and lung function.

Results

Plasma resistin levels were only marginally higher in CF than in healthy control subjects. By contrast, sputum resistin levels were very high in CF, reaching 50–100 fold higher levels than in plasma. Among CF patients, higher plasma resistin levels were associated with allergic bronchopulmonary aspergillosis, and higher sputum resistin levels were associated with CF-related diabetes. Mechanistically, in vitro release of neutrophil primary granules was concomitant with resistin secretion. Overall, sputum resistin levels were negatively correlated with CF lung function, independently of other variables (age, sex, and genotype).

Conclusions

Our data establish relationships between resistin levels in the plasma and sputum of CF patients that correlate with disease status, and identify resistin as a novel mechanistic link between neutrophilic inflammation and lung disease in CF.  相似文献   
110.
目的 探讨外胚叶发育不全(EDA)基因及其受体(EDAR)基因在斑马鱼早期咽齿发育过程中的表达模式,为进一步研究其在牙齿发育过程中的功能奠定基础。方法 提取受精后48 h(48 hpf)的斑马鱼胚胎总RNA,之后逆转录合成cDNA,以该cDNA为模板,特异性扩增斑马鱼咽齿特异性标记基因dlx2b、Eda信号通路相关基因eda及edar基因片段,用TA克隆试剂盒将这3个基因片段分别连接到pGEMT载体上,将对应质粒用聚合酶链反应(PCR)线性化,以PCR线性化做模板,选择相应的RNA聚合酶体外转录,合成dlx2b、eda及edar基因的反义mRNA探针。收集36、48、56、60、72、84 hpf的斑马鱼胚胎,运用全胚原位杂交技术检测eda及edar基因在斑马鱼咽齿发育部位的表达分布。比较原位杂交结果eda及edar表达区域与斑马鱼咽齿特异性标记基因dlx2b所指示咽齿部位的关系。结果 获得了dlx2b、eda及edar基因的反义mRNA探针。原位杂交结果显示,48~72 hpf时eda及edar在鳃弓牙齿相应部位可见强棕褐色阳性信号,与dlx2b所指示咽齿部位吻合。结论 Eda信号通路配体与受体在斑马鱼咽齿早期发育过程中即牙齿发生至形态发生阶段于咽齿部位特异性强表达,这一结果显示该信号通路可能参与斑马鱼咽齿早期发育的调控。  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