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   119796篇
  免费   6832篇
  国内免费   748篇
耳鼻咽喉   1160篇
儿科学   3863篇
妇产科学   2821篇
基础医学   17333篇
口腔科学   4181篇
临床医学   10760篇
内科学   27009篇
皮肤病学   3015篇
神经病学   12258篇
特种医学   2842篇
外国民族医学   1篇
外科学   10735篇
综合类   424篇
一般理论   49篇
预防医学   11440篇
眼科学   1876篇
药学   8368篇
中国医学   444篇
肿瘤学   8797篇
  2024年   141篇
  2023年   1172篇
  2022年   2532篇
  2021年   4197篇
  2020年   2588篇
  2019年   3465篇
  2018年   3987篇
  2017年   3033篇
  2016年   3525篇
  2015年   3870篇
  2014年   5082篇
  2013年   6648篇
  2012年   10017篇
  2011年   10396篇
  2010年   5718篇
  2009年   4838篇
  2008年   8335篇
  2007年   8231篇
  2006年   7561篇
  2005年   7031篇
  2004年   6311篇
  2003年   5612篇
  2002年   4984篇
  2001年   592篇
  2000年   421篇
  1999年   644篇
  1998年   877篇
  1997年   693篇
  1996年   587篇
  1995年   484篇
  1994年   470篇
  1993年   371篇
  1992年   311篇
  1991年   211篇
  1990年   212篇
  1989年   201篇
  1988年   181篇
  1987年   159篇
  1986年   165篇
  1985年   117篇
  1984年   140篇
  1983年   134篇
  1982年   161篇
  1981年   121篇
  1980年   129篇
  1979年   75篇
  1978年   79篇
  1977年   72篇
  1976年   59篇
  1974年   54篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
11.
We developed a self-administered questionnaire for screening the most common adult-onset dystonias. It was tested in 90 first-degree relatives of 22 adult-onset dystonia patients, yielding 79% sensitivity and 94% specificity. Simulation of a case-finding procedure based on serial application of the questionnaire and clinical examination of both subjects screening positive and subjects screening negative who had < 8 years of schooling increased sensitivity to 95% and specificity to 100%. This questionnaire may be an important screening resource for familial aggregation studies to be used in the context of a complex case-finding procedure.  相似文献   
12.
Spinocerebellar ataxia (SCA) types 2 and 3 are autosomal-dominant neurodegenerative disorders caused by mutations in two different genes. We identified mutations for SCA2 and SCA3 segregating simultaneously in a single Brazilian family. The index patient had SCA2, whereas her two second-degree cousins had SCA3. Disease was more rapidly progressive in the SCA2 patient, who presented severe brainstem and pancerebellar atrophy, as opposed to the two SCA3 patients, who had only mild cerebellar vermian atrophy. In such situations, molecular confirmation of all patients may avoid misdiagnosis of SCA subtypes and eventual errors in predictive testing of unaffected family members.  相似文献   
13.
14.
BACKGROUND: Oral hairy leukoplakia (OHL) may be an indicator of the progression of Human Immunodeficiency Virus (HIV)-induced immuno-depression, and the evaluation of risk factors leading to OHL is important in the management of these HIV-infected patients. However, there are few studies that analyze risk factors leading to OHL in the Brazilian population. The aim of this case-control study is to present data about prevalence rates and risk factors leading to OHL in a sample of HIV-infected adults in Brazil. METHODS: This case-control study included 111 HIV-infected patients treated at a clinic for sexually transmitted diseases and HIV. In the initial examinations with dentists, variables were collected from all patients. Diagnosis of OHL was performed in accordance with the International Classification System and cytological features. The Fisher and the chi-squared tests were used for statistical analysis. The proportional prevalence and odds ratio were estimated. RESULTS: Outcome presented a positive, statistically significant association among the presence of OHL and viral load of 3000 copies/mul or greater (P = 0.0001; odds ratio (OR) = 5.8), presence of oral candidiasis (P = 0.0000; OR = 11.1), previous use of fluconazole (P = 0.0000; OR = 24.6), and use of systemic acyclovir (P = 0.032; OR = 4.3). Antiretroviral medication presented a negative, statistically significant association with the presence of OHL (P = 0.002; OR = 8.4). CONCLUSIONS: Prevalence of OHL was 28.8%. Viral load, oral candidiasis, previous use of fluconazole, and systemic acyclovir were determined to be risk factors for OHL. Antiretroviral medication proved to be protective against the development of OHL.  相似文献   
15.
BACKGROUND: In the central nervous system, several neuropeptides are believed to be involved in the pathophysiology of Alzheimer's disease (AD). Indeed, previous studies have documented that glucagon-like peptide 1 (GLP-1) possesses neurotropic properties and can reduce amyloid-beta peptide levels in the brain in vivo. Moreover, the concentrations of neuropeptide Y (NPY) seem to be altered in the cerebrospinal fluid of patients with AD and in subjects with major depression. Finally, among the modifications induced by aging, a dysregulation of the ghrelin-growth hormone (GH) system has been reported. METHODS: We investigated the plasma concentrations of these neuropeptides in 14 subjects with AD. Data obtained from these patients were compared with data from an age- and weight-matched healthy group. RESULTS: No significant differences were found between the two groups in relation to plasma levels of GLP-1, NPY, ghrelin and GH. Peripheral NPY concentrations were positively correlated with ghrelin levels in both groups, and with plasma GLP-1 concentration only in controls. CONCLUSION: On the basis of our results, peripheral levels of these neuropeptides seem not to serve as biochemical markers of AD.  相似文献   
16.
17.
18.
19.
Idiopathic Headache as a Possible Risk Factor for Phantom Tooth Pain   总被引:1,自引:0,他引:1  
Following tooth pulp extirpation, some subjects suffer from persistent pain which affects edentate sites in absence of any local pathology. As regards this peculiar pain, called phantom tooth pain (PTP), what is puzzling is the fact there is a low prevalence of PTP in a very large population showing identical conditions of tooth pulp extirpation. The present investigation indicates that PTP mainly affects migraine (M) and cluster headache (CH) sufferers, whereas it does not affect subjects who have a negative personal and family history for idiopathic headache (IH). These results circumscribe the presence of PTP to a specific section of the population. The present results, besides indicating that PTP may be the result of a peculiar neuronal predisposition relating to IH pathogenesis, suggests some practical therapeutic hints. In fact, successful anti- M and anti-CH prophylactic treatment greatly improve PTP syndrome.  相似文献   
20.
Pressure ulcers are a high-risk, high-volume, and high-cost problem for persons with disabilities. This article describes four tools published in the literature and reports the validity, reliability, strengths, and limitations of each. These tools include the Pressure Ulcer Scale for Healing (PUSH), the Pressure Sore Status Tool (PSST), the Sussman Wound Healing Tool (SWHT), and the Sessing Scale. Rehabilitation nurses should use a consistent framework with accurate quantification to assess, document, and monitor changes in pressure ulcers over time. Such a measurement tool must prove valid for the disabled population in which the tool is used. This will enable healthcare providers to communicate more effectively and evaluate the therapeutic plan of care.  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