首页 | 官方网站   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   1170篇
  免费   86篇
  国内免费   8篇
医药卫生   1264篇
  2023年   3篇
  2022年   11篇
  2021年   24篇
  2020年   13篇
  2019年   17篇
  2018年   33篇
  2017年   24篇
  2016年   17篇
  2015年   29篇
  2014年   47篇
  2013年   40篇
  2012年   46篇
  2011年   51篇
  2010年   52篇
  2009年   46篇
  2008年   48篇
  2007年   37篇
  2006年   64篇
  2005年   25篇
  2004年   42篇
  2003年   37篇
  2002年   17篇
  2001年   19篇
  2000年   15篇
  1999年   13篇
  1998年   30篇
  1997年   50篇
  1996年   47篇
  1995年   39篇
  1994年   35篇
  1993年   37篇
  1992年   24篇
  1991年   13篇
  1990年   15篇
  1989年   18篇
  1988年   20篇
  1987年   15篇
  1986年   10篇
  1985年   12篇
  1984年   12篇
  1983年   14篇
  1982年   20篇
  1981年   15篇
  1980年   12篇
  1979年   9篇
  1978年   5篇
  1977年   6篇
  1976年   18篇
  1975年   9篇
  1971年   2篇
排序方式: 共有1264条查询结果,搜索用时 46 毫秒
21.
22.
The world-wide rise in obesity parallels growing concerns of global warming and depleting natural resources. These issues are often considered separately but there may be considerable benefit to raising awareness of the impact of dietary behaviours and practices on the food supply. Australians have diets inconsistent with recommendations, typically low in fruit and vegetables and high in energy-dense nutrient-poor foods and beverages (EDNP). These EDNP foods are often highly processed and packaged, negatively influencing both health and the environment. This paper describes a proposed dietary assessment method to measure healthy and sustainable dietary behaviours using 4-days of food and beverage images from the mobile food record (mFR) application. The mFR images will be assessed for serves of fruit and vegetables (including seasonality), dairy, eggs and red meat, poultry and fish, ultra-processed EDNP foods, individually packaged foods, and plate waste. A prediction model for a Healthy and Sustainable Diet Index will be developed and tested for validity and reliability. The use of the mFR to assess adherence to a healthy and sustainable diet is a novel and innovative approach to dietary assessment and will have application in population monitoring, guiding intervention development, educating consumers, health professionals and policy makers, and influencing dietary recommendations.  相似文献   
23.
24.
25.
Aims To explore the validity of Developmental Behaviour Checklist‐Autism Screening Algorithm (DBC‐ASA) as a screening instrument for autism among children with intellectual disabilities. Method Data were collected from the case notes of 109 children with intellectual disabilities attending a specialist clinic in the UK. Results The mean score of the DBC‐ASA was significantly higher (t = 6.1; P < 0.001) among children with autism compared with those without. The DBC‐ASA score of 20 yielded a sensitivity of 0.9 and specificity of 0.6, and a score of 18 yielded a sensitivity of 0.92 and specificity of 0.5. The receiver–operating characteristic for the DBC‐ASA score of 20 yielded a large area under the curve (AUC) (0.864) for children with intellectual disabilities when compared against the International Classification of Diseases 10th Revision, Research Diagnostic Criteria (ICD10 DRC) diagnosis of autism. Conclusions The DBC‐ASA score may be able to discriminate between children with intellectual disabilities with and without autism.  相似文献   
26.
Cytogenetic and histologic correlations in malignant lymphoma   总被引:9,自引:0,他引:9  
Although a number of studies have indicated correlations between histologic subtypes of tumors and certain nonrandom chromosome changes, cytogenetic studies of lymphoma are in an early stage compared to those of leukemia. No comprehensive analysis of available data has so far been attempted in the literature either. Here we present an analysis of chromosome changes and their correlation with subtypes of lymphoma studied by conventional histology and cell surface markers, as observed in two sets of data: a group of 65 karyotypically abnormal tumors sequentially ascertained and studied by us during the period January 1, 1984 to April 30, 1985, and a larger data set derived by combining our data with those from two published series from the University of Minnesota that are comparable to our data. These combined data, which comprise the largest data set on the cytogenetics of lymphomas assembled so far, enabled a comprehensive analysis of correlation between chromosome change and tumor histology and the patterns of chromosome instability in these tumors. We found several significant associations, some previously described and others now recognized, between nonrandom chromosome gains, breaks, translocations, and deletions and histologic subtypes of tumors that characterize lymphomas. The data indicate that finding of chromosome breaks at certain sites (eg, 8q24, 14q32, 18q21) is of diagnostic value in dealing with cases of unusual lymphoma. Furthermore, nonrandom chromosome breakage exhibited three distinct patterns that reflected three levels of etiologically relevant genetic change.  相似文献   
27.
BACKGROUND: The purpose of this study was to evaluate the accuracy and reproducibility of three-dimensional volume measurements by high-resolution endoluminal ultrasound in an esophageal varix model. METHODS: An esophageal varix model was made by filling three esophageal dilatation catheters with various volumes of water. A 20 MHz ultrasonography transducer was then pulled along the length of the catheters at a constant rate (1.25 mm/sec) while videotaping the procedure. Cross-sectional surface area measurements of each catheter were taken every second and the cross-sectional surface area was multiplied by the length of each catheter, as determined by high-resolution endoluminal ultrasound, to determine the volume in each catheter. Interobserver variability was calculated, and three-dimensional reconstruction was performed. RESULTS: The measured volumes corresponded closely with the actual volumes with an error ranging from 0% to 15.4%. The correlation between actual and measured volumes was r = 0.988. The interobserver variability ranged from r = 0.951 to r = 0.994. Actual esophageal varices were then imaged in a similar fashion to determine the feasibility of this method in patients with esophageal varices. CONCLUSIONS: High-resolution endoluminal ultrasound is an accurate and reproducible method of measuring volumes in an esophageal varix model and can be used in a clinical setting to determine variceal volume. Volume studies are now underway in human subjects.  相似文献   
28.
29.
Immunoglobulin V regions and the B cell   总被引:7,自引:2,他引:7  
Stewart  AK; Schwartz  RS 《Blood》1994,83(7):1717-1730
  相似文献   
30.
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-23

京公网安备 11010802026262号