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   21851篇
  免费   2275篇
  国内免费   380篇
耳鼻咽喉   87篇
儿科学   875篇
妇产科学   244篇
基础医学   1160篇
口腔科学   551篇
临床医学   3274篇
内科学   2986篇
皮肤病学   101篇
神经病学   1949篇
特种医学   282篇
外科学   2279篇
综合类   2149篇
现状与发展   1篇
一般理论   4篇
预防医学   5788篇
眼科学   127篇
药学   981篇
  40篇
中国医学   476篇
肿瘤学   1152篇
  2024年   80篇
  2023年   527篇
  2022年   848篇
  2021年   1151篇
  2020年   1094篇
  2019年   1104篇
  2018年   986篇
  2017年   1006篇
  2016年   909篇
  2015年   844篇
  2014年   1480篇
  2013年   1908篇
  2012年   1280篇
  2011年   1386篇
  2010年   1058篇
  2009年   1130篇
  2008年   1147篇
  2007年   1084篇
  2006年   865篇
  2005年   687篇
  2004年   587篇
  2003年   505篇
  2002年   418篇
  2001年   326篇
  2000年   278篇
  1999年   223篇
  1998年   203篇
  1997年   159篇
  1996年   137篇
  1995年   155篇
  1994年   117篇
  1993年   115篇
  1992年   97篇
  1991年   80篇
  1990年   59篇
  1989年   67篇
  1988年   70篇
  1987年   38篇
  1986年   32篇
  1985年   61篇
  1984年   41篇
  1983年   28篇
  1982年   28篇
  1981年   24篇
  1980年   17篇
  1979年   17篇
  1978年   13篇
  1977年   8篇
  1976年   10篇
  1972年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
张春玲  徐贵发 《卫生研究》1994,23(5):294-297
对山东省荣成市石岛镇大渔岛村91户398名散居渔民膳食结构及营养状况调查的结果表明:①蛋白质和热能人均摄入量占平均供给量的115.4%和112.2%,其它营养素除维生素B2占83.3%以外均摄入较充足。蛋白质、脂肪、碳水化合物的热量构成比分别为11.3%、27.6%、61.1%。②查体中未发现严重的营养缺乏症。③体重指数超过正常者占13.2%。④体重指数与收缩压、舒张压经相关回归分析,呈显著相关。⑤大渔岛居民头发锌含量高于泰安农民,铜、铁含量低于泰安农民。  相似文献   
72.
73.
We developed an objective and automatic procedure to assess the severity of levodopa-induced dyskinesia (LID) in patients with Parkinson's disease during daily life activities. Thirteen patients were continuously monitored in a home-like situation for a period of approximately 2.5 hours. During this time period, the patients performed approximately 35 functional daily life activities. Behavior of the patients was measured using triaxial accelerometers, which were placed at six different positions on the body. A neural network was trained to assess the severity of LID using various variables of the accelerometer signals. Neural network scores were compared with the assessment by physicians, who evaluated the continuously videotaped behavior of the patients off-line. The neural network correctly classified dyskinesia or the absence of dyskinesia in 15-minute intervals in 93.7, 99.7, and 97.0% for the arm, trunk, and leg, respectively. In the few cases of misclassification, the rating by the neural network was in the class next to that indicated by the physicians using the AIMS score (scale 0-4). Analysis of the neural networks revealed several new variables, which are relevant for assessing the severity of LID. The results indicate that the neural network can accurately assess the severity of LID and could distinguish LID from voluntary movements in daily life situations.  相似文献   
74.
Two hundred and thirty-five tenants living in sheltered housing in Scotland were surveyed to identify the extent of under-nutrition and the social factors which contribute to its development. A validated 24 h recall and the nutrient checklist published by NAGE were used to evaluate patterns of dietary intake. A questionnaire was developed which included scales designed to measure depression, social engagement, cognitive function, mobility and functional ability. The results show considerable evidence of a number of major nutrients in which there were low intakes. In order to express the extent of poor nutrition, a nutrient score was developed where points are awarded based on the number of nutrients falling below the Lower Reference Nutrient Intake, the Estimated Average Requirement or below half the daily Estimated Average Requirement.  相似文献   
75.
Two sample groups of elderly were compared from a population living in South London. One group attended a local day centre (a socially orientated establishment), and the other attended a local day hospital (a therapeutically orientated establishment).
The aim of the study was to compare nutritional intake, functional status and muscle strength between these two groups.
The mean nutritional intakes of the day hospital and day centre attenders were similar. Intake of macronutrients, with the exception of fibre, met Recommended Daily Allowances (RDAs) in both groups. In take of folic acid, vitamin D and zinc fell below recommendations in both groups.
Low intake of folic acid was improved by supplementation, and some individual blood levels of folate reflected this. Blood folate levels were generally within normal limits. Low intake of vitamin D was improved by supplementation, but blood levels were generally normal anyway. There was, however, a tendency for the more dependent day hospital patients to have lower vitamin D levels. This group also had less sunshine exposure.
Communal dining, whether in the setting of day hospital or day centre, may have been an essential means of bolstering nutritional intake for many 'at risk' elderly.
There were significant differences in functional status and muscle strength in favour of the day centre group and these indicate that anthropometric indices rather than nutritional or biochemical indices were the most reliable markers of disease and disability in this study.
The effect of fortifying local meals-on-wheels was also highlighted, and suggests that this may be one means of preventing nutritional deficiencies in the vulnerable, house-bound elderly.
Alcohol intake was reported as being modest. However, discrepancies were noted on review of biochemical indices known to be influenced by alcohol intake.  相似文献   
76.
This study examined the contribution of the quality of life (QoL) domains physical, social and psychological functioning to the explanation of overall QoL. Various disorders may differentially affect QoL domains due to disease-specific factors and, consequently, the relationship between QoL domains and overall QoL may vary between diseases. We therefore studied this relationship for several diseases as well as the differential impact of these diseases on QoL. The present study had a cross-sectional design. We selected patients (aged 57 years and older) with one of the following eight chronic medical conditions: lung disorder, heart condition, hypertension, diabetes mellitus, back problems, rheumatoid arthritis, migraine, or dermatological disorders. The total group of respondents included 1457 patients and 1851 healthy subjects. Regression analyses showed that the domain of psychological functioning contributed to overall QoL for all disorders, whereas physical and social functioning contributed to overall QoL for some disorders. Differences were found between most patient groups and healthy subjects with respect to physical functioning; with respect to social and psychological functioning some groups differed from the healthy group. Explanations for the findings and implications for clinical practice are discussed.  相似文献   
77.
Background/purpose: The localized or generalized skin thickness detected on mammography may reflect an underlying pathology of breast or a systemic disease involving the skin. The aim of this report is to describe the range of normal breast skin thickness in women using a film-screen mammographic technique.
Methods: Measurement of the mammographic skin thickness over different parts of the breast was performed in 144 women who had normal findings in a combined mammographic and ultrasonographic examination. Patients were grouped as premenopause, postmenopause and surgical menopause who were under continuous oestrogen treatment. The skin thickness in four regions (superior, inferior, medial, lateral) of both breasts was compared, and their relations with age, breast size, menopausal and hormonal status were investigated. The interobserver reliability was tested in a small subgroup of patients.
Results: Interobserver agreement was good for all measurements. The range of normal breast skin thickness was between 0.50 and 3.10 mm. There were no differences in skin thickness between the corresponding regions of the breasts, with significant differences between the regions in the same breast. While breast size increased with age, skin thickness decreased in all regions.
Conclusion: The breast size, age, regional variations and hormonal status of the patients should be considered when defining the normal range of skin thickness in mammographic examinations. We assume that upper limit of mammographic skin thickness should be set as 3.0 mm, regardless of the focal spot size and film-focus distance.  相似文献   
78.
This study was designed to evaluate the reproducibility, validity and responsiveness of a health-related quality of life (HRQOL) battery that was assembled for the evaluation of antidepressant therapy. The Montgomery-Asberg Depression Rating Scale was used to measure severity of depression. The HRQOL battery contained measures of energy and fatigue, social behaviour, cognitive function, home and work role function, and general well-being (i.e., health perceptions, life satisfaction) selected from previously developed and validated instruments. The clinical investigators and research nurses reported on difficulty in using the HRQOL battery. Most patients were able to complete the questionnaire without problems within 10 min. Reproducibility was very good with intraclass correlation coefficients ranging from 0.74 to 0.97. The HRQOL scales showed evidence of good concurrent validity. The scales were moderately correlated with MADRS scores (r=0.30–0.62). The magnitude of these correlations indicate that HRQOL scales are related to depression measures, but they are not alternative measures of depression. Changes in MADRS scores were associated with changes in all scales, except for work behaviour, indicating that improvements in depression ratings also resulted in improvements in health status and well-being. The HRQOL scales included in this study were found to be reliable, reproducible, and valid and no appreciable burden was placed on patients or investigators participating in the study. With the exception of the Work Behaviour scale, the HRQOL scales were very responsive to changes in depression severity. This brief HRQOL instrument can provide a comprehensive assessment of the outcomes of antidepressant treatment.This research was supported by a grant from Pfizer International.  相似文献   
79.
Status dystonicus (SD) is a life threatening disorder that develops in patients with both primary and secondary dystonia, characterized by acute worsening of symptoms with generalized and severe muscle contractions. To date, no information is available on the best way to treat this disorder. We review the previously described cases of SD and two new cases are reported, one of which occurring in a child with static encephalopathy, and the other one in a patient with pantothenate kinase-associated neurodegeneration. Both patients were admitted to an intensive care unit and treated with midazolam and propofol. This approach proved to be useful in the former while the progressive nature of the dystonia of the second patient required the combination of intrathecal baclofen infusion and bilateral pallidal deep brain stimulation. We believe that a rapid and aggressive approach is justified to avoid the great morbidity and mortality which characterize SD. Our experience, combined with the data available in the literature, might permit to establish the best strategies in managing this rare and severe condition.  相似文献   
80.
A patient with chronic cerebral paragonimiasis began to have new motor seizures of the right face manifested by clonic contractions that occurred several hundred times a day, consistent with simple partial status epilepticus. Ictal electroencephalogram discharges started from the left frontal region and then spread to the left hemisphere with left frontal maximum. But clinical seizures were limited to the right face. The frequent partial seizures were controlled by the intravenous infusion of phenytoin. Brain magnetic resonance imaging showed multiple conglomerated round nodules with encephalomalacia in the left temporal and occipital lobes. Applying the technique of ictal-interictal single-photo emission computed tomography subtraction, the authors were able to localize the focal ictal-hyperperfusion on left precentral cortex adjacent to the lesions that correspond to the anatomical distribution of left face motor area.  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