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   13496篇
  免费   930篇
  国内免费   37篇
耳鼻咽喉   137篇
儿科学   499篇
妇产科学   368篇
基础医学   2033篇
口腔科学   199篇
临床医学   1620篇
内科学   2465篇
皮肤病学   337篇
神经病学   1622篇
特种医学   311篇
外科学   1374篇
综合类   68篇
一般理论   13篇
预防医学   1069篇
眼科学   234篇
药学   863篇
中国医学   17篇
肿瘤学   1234篇
  2023年   91篇
  2022年   98篇
  2021年   300篇
  2020年   249篇
  2019年   324篇
  2018年   364篇
  2017年   306篇
  2016年   372篇
  2015年   409篇
  2014年   504篇
  2013年   715篇
  2012年   1067篇
  2011年   1034篇
  2010年   633篇
  2009年   557篇
  2008年   864篇
  2007年   895篇
  2006年   878篇
  2005年   836篇
  2004年   763篇
  2003年   719篇
  2002年   677篇
  2001年   87篇
  2000年   57篇
  1999年   111篇
  1998年   158篇
  1997年   126篇
  1996年   102篇
  1995年   103篇
  1994年   63篇
  1993年   76篇
  1992年   51篇
  1991年   57篇
  1990年   46篇
  1989年   32篇
  1988年   38篇
  1987年   24篇
  1986年   30篇
  1985年   30篇
  1984年   29篇
  1983年   37篇
  1982年   48篇
  1981年   29篇
  1980年   36篇
  1979年   32篇
  1978年   19篇
  1977年   22篇
  1976年   29篇
  1974年   22篇
  1969年   16篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
ABSTRACT This paper describes further testing of an Activity Index introduced by Hamrin & Wohlin, which was designed especially to evaluate the functional capacity of patients after stroke. The results of reliability tests and validation procedures are presented, in particular in comparison with the internationally well known Katz Index of Independence in Activities of Daily Living. The standardised item alpha reliability coefficient for the Activity Index was 0.97 for the total score (n= 231) and the corresponding value for the Katz Index of ADL was 0.94. Using factor analysis with four factors, 88.3% of the variances of the 16 variables of the Activity Index could be explained, and the different variables were found to have a logical distribution between the factors. In a two-factor analysis of the Katz Index of ADL, 89.6% of the variance of the six variables could be explained, and the hierarchical structure of the test was recognised. Compared with the Katz Index of ADL, the Activity Index had a higher predictive capacity and it also better measured changes in the patient's functional ability between different test occasions.  相似文献   
33.
34.
The occurrence of behavioural problems in a population-based series of children with infantile hydrocephalus (non-spina bifida) was analysed, using parent questionnaires. Children with both infantile hydrocephalus and mental retardation had significantly more behavioural problems compared with those with no mental retardation and controls. Inattentiveness and hyperactivity were particularly typical. No differences were found between children with infantile hydrocephalus and no mental retardation and the control group.  相似文献   
35.
The purpose of this study was to examine the effect of exacerbations on mild to moderate asthmatic patients' preference-based, health-related, quality of life scores and also to describe the effect of these exacerbations on daily life. In a survey, 100 mild to moderate asthmatic patients in the United Kingdom were asked to rate three different health marker states on a scale between 0 (death) and 100 (perfect health), defined as: your asthma of today, a mild exacerbation, and a severe exacerbation of asthma. They were also asked to describe their symptoms and what they did when experiencing an exacerbation. During exacerbations the vast majority of asthmatic patients have significant symptoms and consume a considerable amount of health care resources, which often overlap. The health marker state “your asthma of today” was given a mean score of 81.0, a mild exacerbation a score of 62.1, and a severe exacerbation a score of 25.6, indicating a large impact on patients' daily life and their health-related quality of life. In conclusion, asthmatic patients are severely affected in their health and daily living by mild and severe exacerbations. Considerable effort should be made to reduce the number and severity of exacerbations.  相似文献   
36.
37.
Epipedobates flavopictus, Dendrobatidae, is a small aposematic frog found in Brazilian Cerrado bioma. In the present work, we isolated and characterized chemically the most abundant alkaloids present in the cutaneous extract of E. flavopictus. The specimens were collected in Pirenópolis (Goiás, Brazil), their skins were removed and extracted with methanol, and submitted to purification by HPLC and identification by gas chromatography and mass spectrometry. Pumiliotoxin 251D, histrionicotoxin 285Da and two decahydroquinolines, 219A and 243A, were identified. The pumiliotoxin 251D was tested on isolated frog sciatic nerve and on isolated guinea pig ileum muscle. The pumiliotoxin 251D slightly reduced the action potentials amplitude of frog sciatic nerve. The crude skin extract of E. flavopictus and the pumiliotoxin 251D produced rhythmic contractions and increased the muscular tension on isolated guinea pig ileum.  相似文献   
38.
The catechol-O-methyltransferase (COMT) Val158Met polymorphism modulates executive functions and working memory and recent neuroimaging studies implicate an association with emotional processing. We examined the relationship between the COMT Val158Met polymorphism and facial emotion recognition and differentiation in 100 healthy individuals. Compared to Met homozygosity, Val homozygosity was associated with better and faster recognition of negative facial expressions such as anger and sad. Our study provides evidence for a possible influence of the COMT polymorphism on emotion recognition abilities in healthy subjects. Additional research is needed to further define the neurocognitive phenotypes associated with COMT polymorphisms.  相似文献   
39.
OBJECTIVE: Apathy is among the most frequent neuropsychiatric symptoms in dementia, particularly Alzheimer disease. The Apathy Evaluation Scale (AES) has been widely employed for assessing apathy in different patient groups. To further facilitate the usage of the AES, an abbreviated version was constructed. METHOD: On basis of a sample of 356 nursing home residents, a cross-validation procedure was carried out to develop a brief version of the AES. According to a thorough clinical examination, 85% of the residents were demented, 8% presented with mild cognitive impairment, whereas 7% did not present any cognitive deficits. After subdividing the patient group into two matched samples, the first subsample was used to identify problematic items due to defined psychometric and content-related criteria. The original 18-item scale was thus reduced to 10 items. Psychometric properties of the shortened version were subsequently reassessed in the second subsample. RESULTS: The short version demonstrated favorable psychometric properties that could be confirmed by cross-validation with the second sample. Correlations with the original full-length version were high (r = 0.97 for both subsamples); the shortened scale yielded no substantial losses regarding internal consistency or construct validity (correlations with the respective subscales of the Neuropsychiatric Inventory). CONCLUSION: The frequency of apathetic symptoms in the nursing home residents included confirms the clinical importance of apathy for understanding dementia. Given this specific patient population, setting, and mode of data collection, the short-version AES seems to be a valuable and time-efficient instrument for assessing apathy.  相似文献   
40.
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