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   1214篇
  免费   90篇
  国内免费   2篇
耳鼻咽喉   9篇
儿科学   54篇
妇产科学   22篇
基础医学   217篇
口腔科学   39篇
临床医学   143篇
内科学   239篇
皮肤病学   15篇
神经病学   115篇
特种医学   23篇
外科学   116篇
综合类   6篇
预防医学   83篇
眼科学   56篇
药学   87篇
中国医学   13篇
肿瘤学   69篇
  2024年   3篇
  2023年   23篇
  2022年   65篇
  2021年   80篇
  2020年   47篇
  2019年   71篇
  2018年   66篇
  2017年   61篇
  2016年   65篇
  2015年   63篇
  2014年   60篇
  2013年   87篇
  2012年   124篇
  2011年   124篇
  2010年   59篇
  2009年   39篇
  2008年   60篇
  2007年   53篇
  2006年   43篇
  2005年   27篇
  2004年   37篇
  2003年   19篇
  2002年   15篇
  2001年   3篇
  2000年   2篇
  1999年   1篇
  1998年   1篇
  1997年   2篇
  1996年   1篇
  1994年   2篇
  1988年   1篇
  1982年   1篇
  1981年   1篇
排序方式: 共有1306条查询结果,搜索用时 15 毫秒
61.
In today’s society, sleep disturbances and back pain are both common problems which threaten health. Although some studies have focused on the effects of sleep disturbances on back pain, no meta-analysis has been done. The purpose of this study is to systematically review and perform a meta-analysis on the effects of sleep disturbances on back pain. A literature search in PubMed, Scopus and EMBASE with keywords until June 2019 was performed. The eligible articles were evaluated qualitatively and the results were pooled using random effects. The publication bias and the degree of heterogeneity were examined. In all, 21 studies were included in the meta-analysis. Sleep disturbances were associated with back pain (odds ratio 1.52; confidence interval [CI] 1.37–1.68; P < 0.001). In men, the odds ratio was 1.49 (CI 1.34–1.65; P < 0.001). In women, the odds ratio was 1.56 (CI 1.33–1.81; P < 0.001). Begg’s test (P = 0.856) and Egger test (P = 0.188) did not show any publication bias. A funnel plot and trim-and-fill method showed publication bias, and heterogeneity was also high. Sleep disturbance is associated with risk of back pain. Improving sleep can be a deterrent against back pain. Therefore, interventions to reduce sleep disturbances can help to improve health. On the other hand, the relationship between sleep disturbances and back pain can be two-sided, and back pain can also lead to sleep disturbances. Not only in view of the lifetime prevalence and the multifactorial impairments of those affected, but also in consideration of social and economic burdens, this issue will remain of considerable importance.  相似文献   
62.
ObjectiveTo explore the relationship between temperament and character traits in Cloninger’s psychobiological theory and mental disorders.Methods: A systematic literature search was conducted of five international databases for all articles published in English between January 1990 and April 2019 (PROSPERO-CRD42019133214). Owing to heterogeneity, pooled estimates of correlations for personality disorders and standardized mean differences for case–control studies related to other mental disorders were calculated using the random-effects method.ResultsThe pooled effect sizes obtained from 149 studies showed that high harm avoidance (related to 22/24 diagnostic categories), low self-directedness (21/23), low cooperativeness (17/23), high self-transcendence (14/23), low reward dependence (11/24), high novelty-seeking (10/24), low novelty-seeking (7/24), high persistence (2/23), low persistence (2/23) and high reward dependence (2/24) were related to psychopathology.ConclusionsAll traits provided unique psychobiological tools for differential diagnosis of mental disorders. However, high harm avoidance and low self-directedness played a canonical role in psychopathology. Despite the study limitations, additional studies are warranted to evaluate the differential diagnoses suggested by the present model.  相似文献   
63.
Background: Atherosclerosis is a multifactorial disorder with chronic inflammatory conditions in which immune cells play a significant role in its pathogenic process. Regulatory T cells (Treg), as a part of immune system, are involved in controlling auto-immune and inflammatory diseases. Tregs have been shown to play an atheroprotective role and may also promote plaque stabilization. Objective: To assess if inducible costimulatory molecule (ICOS) expression on one subtype of Treg cells with high suppressive potential correlates with the pathogenesis of atherosclerosis. Methods: Patients with myocardial infarction (MI) and/or stable angina (SA), diagnosed as atherosclerosis by angiography, and a group of individuals with normal coronary angiography (NCA) were recruited for the present study. Peripheral blood mononuclear cells (PBMCs) were prepared and the expression of ICOS, Foxp3 and CD4 molecules was tested by flowcytometry. Results: The percentage of CD4+Foxp3+ Treg cells was reduced in MI group compared to NCA and SA groups (p<0.005). Evaluation of the two Treg subsets according to ICOS expression showed a decreased ICOS+/ICOS- Treg ratio in MI and SA groups compared to NCA individuals (p=0.002 and p=0.048, respectively). Conclusion: The present data indicate that Tregs and its ICOS+ subsets are decreased in patients with MI or SA, suggesting a potential role for Treg in atherosclerosis progression or onset of acute coronary syndrome.  相似文献   
64.
Pericardial patch has been used to repair cardiac defects; however, its strength as an aortoplasty patch to tolerate systemic pressure is a matter of debate. We report an aneurysmal dilatation of pericardial patch in aortoplasty. Our patient was a 56-year-old female known case of rheumatic heart disease that underwent redoes mitral and aortic valve replacements along with Manouguian aortoplasty at the age of 44?years old. After 2?months, she was readmitted with a diagnosis of endocarditis. Echocardiography revealed a small cavity in the posterior wall of the aorta. She responded to medical therapy and discharged in a good condition. Twelve years later, she was scheduled to undergo reoperation due to a severe paraprosthetic aortic valve leakage and a pericardial patch aneurysm. The leaking prosthetic aortic valve was explanted and the aneurysmal tissue was replaced with a polyethylene terephthalate patch.  相似文献   
65.
66.
67.
Renal lymphangiomatosis is an exceedingly rare disorder characterized by developmental malformation of the lymphatic system surrounding the kidneys. We report a case of bilateral renal lymphangiomatosis in a 21-year-old man who underwent abdominal sonographic examination that revealed numerous cystic areas of various sizes around both kidneys with extension along the renal hilum. Subsequent abdominal CT examination demonstrated bilateral, multilocular, fluid-filled cystic masses with thin walls in the perirenal and peripelvic region. MRI of the patient revealed bilaterally enlarged kidneys with multiple hyperintense lesions in both perirenal spaces and the peripelvic area on T2-weighted images. These cystic spaces appeared hypointense on T1-weighted images with no enhancement in postcontrast images. The diagnosis of renal lymphangiomatosis was made based on typical imaging findings.  相似文献   
68.
69.
Ankylosing spondylitis (AS) is a chronic inflammatory disease, characterized by axial arthritis in which the genetic-environmental factors seem to be involved in the pathogenesis of the disease. This study was performed to investigate the role of polymorphisms of the programmed cell death 1 (PDCD1) gene on susceptibility to AS. In this study, 161 Iranian patients with AS and 208 normal controls were enrolled; two single-nucleotide polymorphisms (SNPs) of the PDCD1 gene PD-1.3 (G, A) in nucleotide position +7146 of intron 4 and PD-1.9 (C, T) in nucleotide +7625 of exon 5 were studied. Analysis of PD-1.3 revealed that 82% of patients and 79% of controls had GG genotype, while GA and AA genotypes were detected in 17% and 0.6% of patients, respectively, and 20% and 1.4% of controls, respectively. Moreover, the genotype CC (PD-1.9) was present in 92% of patients and 97% of controls. Although these differences were not statistically significant between patients and controls, comparisons of genotypes frequencies in the AS patients, based on human leukocyte antigen (HLA)-B27, revealed that all patients who had CT genotype (PD-1.9) were HLA-B27 positive, whereas 30% of patients with CC genotype were HLA-B27 negative. There was no evidence of association for PDCD1 SNPs with AS in our study, but CT genotype (PD-1.9) seems to be associated with HLA-B27 positivity in the patients with AS.  相似文献   
70.
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