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   4195篇
  免费   220篇
  国内免费   21篇
耳鼻咽喉   77篇
儿科学   259篇
妇产科学   20篇
基础医学   325篇
口腔科学   49篇
临床医学   355篇
内科学   1183篇
皮肤病学   54篇
神经病学   312篇
特种医学   134篇
外科学   692篇
综合类   85篇
一般理论   1篇
预防医学   114篇
眼科学   208篇
药学   314篇
中国医学   10篇
肿瘤学   244篇
  2024年   2篇
  2023年   52篇
  2022年   91篇
  2021年   228篇
  2020年   76篇
  2019年   140篇
  2018年   221篇
  2017年   119篇
  2016年   136篇
  2015年   122篇
  2014年   213篇
  2013年   285篇
  2012年   402篇
  2011年   396篇
  2010年   202篇
  2009年   154篇
  2008年   246篇
  2007年   283篇
  2006年   267篇
  2005年   212篇
  2004年   174篇
  2003年   139篇
  2002年   123篇
  2001年   20篇
  2000年   30篇
  1999年   17篇
  1998年   19篇
  1997年   14篇
  1996年   13篇
  1995年   15篇
  1994年   2篇
  1993年   3篇
  1992年   4篇
  1991年   3篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
  1983年   1篇
  1981年   1篇
  1980年   1篇
  1976年   1篇
  1965年   1篇
排序方式: 共有4436条查询结果,搜索用时 15 毫秒
71.
Myocarditis     
Sagar S  Liu PP  Cooper LT 《Lancet》2012,379(9817):738-747
Myocarditis is an underdiagnosed cause of acute heart failure, sudden death, and chronic dilated cardiomyopathy. In developed countries, viral infections commonly cause myocarditis; however, in the developing world, rheumatic carditis, Trypanosoma cruzi, and bacterial infections such as diphtheria still contribute to the global burden of the disease. The short-term prognosis of acute myocarditis is usually good, but varies widely by cause. Those patients who initially recover might develop recurrent dilated cardiomyopathy and heart failure, sometimes years later. Because myocarditis presents with non-specific symptoms including chest pain, dyspnoea, and palpitations, it often mimics more common disorders such as coronary artery disease. In some patients, cardiac MRI and endomyocardial biopsy can help identify myocarditis, predict risk of cardiovascular events, and guide treatment. Finding effective therapies has been challenging because the pathogenesis of chronic dilated cardiomyopathy after viral myocarditis is complex and determined by host and viral genetics as well as environmental factors. Findings from recent clinical trials suggest that some patients with chronic inflammatory cardiomyopathy have a progressive clinical course despite standard medical care and might improve with a short course of immunosuppression.  相似文献   
72.
Marijuana is the most abused recreational drug in the United States. Cannabinoids, the active ingredients of marijuana, affect multiple organ systems in the human body. The pharmacologic effects of marijuana, based on stimulation of cannabinoid receptors CB1 and CB2, which are widely distributed in the cardiovascular system, have been well described. Activation of these receptors modulates the function of various cellular elements of the vessel wall, and may contribute to the pathogenesis of atherosclerosis. Clinically, there are reports linking marijuana smoking to the precipitation of angina and acute coronary syndromes. Recently, large published clinical trials with CB1 antagonist rimonabant did not show any significant benefit of this agent in preventing progression of atherosclerosis. In light of these findings and emerging data on multiple pathways linking cannabinoids to atherosclerosis, we discuss the literature on the role of cannabinoids in the pathophysiology of atherosclerosis. We also propose a marijuana paradox, which implies that inhalation of marijuana may be linked to precipitation of acute coronary syndromes, but modulation of the endocannabinoid system by a noninhalation route may have a salutary effect on the development of atherosclerosis.  相似文献   
73.
Lifelong dietary restriction (DR) is known to have many potential beneficial effects on brain function as well as delaying the onset of neurological diseases. In the present investigation, the effect of late-onset short-term intermittent fasting dietary restriction (IF-DR) regimen was studied on motor coordination and cognitive ability of ageing male rats. These animals were further used to estimate protein carbonyl content and mitochondrial complex I-IV activity in different regions of brain and peripheral organs, and the degree of age-related impairment and reversion by late-onset short-term IF-DR was compared with their levels in 3-month-old young rats. The results of improvement in motor coordination by rotarod test and cognitive skills by Morris water maze in IF-DR rats were found to be positively correlated with the decline in the oxidative molecular damage to proteins and enhanced mitochondrial complex IV activity in different regions of ageing brain as well as peripheral organs. The work was further extended to study the expression of synaptic plasticity-related proteins, such as synaptophysin, calcineurin and CaM kinase II to explore the molecular basis of IF-DR regimen to improve cognitive function. These results suggest that even late-onset short-term IF-DR regimen have the potential to retard age-associated detrimental effects, such as cognitive and motor performance as well as oxidative molecular damage to proteins.  相似文献   
74.
Poor patients in developing countries may not receive permanent pacemakers (PPMs) even as lifesaving measures because of their high cost. In this report we examined whether PPMs that were explanted and donated by funeral homes in the United States could be safely and effectively reused in indigent patients in India. With permission from the deceased patients' families, 121 PPMs were explanted and donated by funeral homes for reuse. These PPMs were sterilized and sent for implantation in needy and indigent patients at a charity hospital in Mumbai, India. From the pool of donated 121 PPMs, 53 (88%, 11 single-chamber PPMs, 21%, and 42 dual-chamber PPMs, 79%) were acceptable for reuse and implanted (37 new implants, 70%, and 16 for battery/generator replacement, 30%) in 53 patients (mean ± SD 64 ± 10 years old, 28 women, 53%). Indications for PPM implantation were complete heart block (n = 27, 51%) and sick sinus syndrome (n = 26, 49%). All patients were alive and well postoperatively. No significant complications including infections or device failures occurred over 19 to 1,827 days (mean 661) of follow-up. Of 40 patients (75%) who were followed locally, 4 (10%) died because of nonpacemaker-related causes; time to death was 121 to 750 days (mean 430) after PPM implantation. All except 2 patients (5%) reported marked improvement in their symptoms. There were only 4 patients (8%) who were previously employed, and all were able to resume their manual labor work. Also, of the women, 27 patients (96%) reported improvement in symptoms enabling them to resume regular household chores as housewives after PPM implantation. In conclusion, with proper device sterilization and handling protocols, reuse of explanted PPMs in poor patients in developing countries is safe and effective. Implantation of donated PPMs can not only save lives but also improve quality of life of needy poor patients.  相似文献   
75.
76.
77.
78.
79.
The aims of this study were to identify which factors may lead to crisis for people with dementia and their carers and identify interventions these individuals believe could help in crisis. Qualitative study using focus groups to compare the perspectives of people with dementia, family carers and healthcare professionals on causes of crises and crisis interventions. To help in a crisis, people with dementia were favourable towards support from family and friends, access to mobile phones and home adaptations to reduce risks. Carers were keen on assistive technology and home adaptation. Both carers and staff valued carer training and education, care plans and well-coordinated care. Staff were the only group emphasizing more intensive interventions such as emergency home respite and extended hours services. In terms of causes of crises, people with dementia focused on risks and hazards in their home, whereas family carers emphasized carer stress and their own mental health problems. Staff, in contrast were concerned about problems with service organization and coordination leading to crises. Physical problems were less commonly identified as causes of crises but when they did occur they had a major impact. Practical interventions such as home adaptations, assistive technology, education and training for family carers, and flexible home care services were highly valued by service users and their families during times of crisis and may help prevent hospital admissions. Specialist home care was highly valued by all groups.  相似文献   
80.
ObjectiveWe determined the clinical impact and developmental changes of auditory-language-related augmentation of gamma activity at 50–120 Hz recorded on electrocorticography (ECoG).MethodsWe analyzed data from 77 epileptic patients ranging 4–56 years in age. We determined the effects of seizure-onset zone, electrode location, and patient-age upon gamma-augmentation elicited by an auditory-naming task.ResultsGamma-augmentation was less frequently elicited within seizure-onset sites compared to other sites. Regardless of age, gamma-augmentation most often involved the 80–100 Hz frequency band. Gamma-augmentation initially involved bilateral superior-temporal regions, followed by left-side dominant involvement in the middle-temporal, medial-temporal, inferior-frontal, dorsolateral-premotor, and medial-frontal regions and concluded with bilateral inferior-Rolandic involvement. Compared to younger patients, those older than 10 years had a larger proportion of left dorsolateral-premotor and right inferior-frontal sites showing gamma-augmentation. The incidence of a post-operative language deficit requiring speech therapy was predicted by the number of resected sites with gamma-augmentation in the superior-temporal, inferior-frontal, dorsolateral-premotor, and inferior-Rolandic regions of the left hemisphere assumed to contain essential language function (r2 = 0.59; p = 0.001; odds ratio = 6.04 [95% confidence-interval: 2.26–16.15]).ConclusionsAuditory-language-related gamma-augmentation can provide additional information useful to localize the primary language areas.SignificanceThese results derived from a large sample of patients support the utility of auditory-language-related gamma-augmentation in presurgical evaluation.  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