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   1838篇
  免费   254篇
  国内免费   19篇
耳鼻咽喉   27篇
儿科学   74篇
妇产科学   27篇
基础医学   186篇
口腔科学   48篇
临床医学   277篇
内科学   350篇
皮肤病学   108篇
神经病学   116篇
特种医学   136篇
外科学   257篇
综合类   100篇
现状与发展   30篇
预防医学   159篇
眼科学   43篇
药学   68篇
中国医学   3篇
肿瘤学   102篇
  2024年   14篇
  2023年   180篇
  2022年   18篇
  2021年   21篇
  2020年   60篇
  2019年   37篇
  2018年   62篇
  2017年   61篇
  2016年   51篇
  2015年   63篇
  2014年   107篇
  2013年   89篇
  2012年   55篇
  2011年   68篇
  2010年   99篇
  2009年   103篇
  2008年   67篇
  2007年   83篇
  2006年   52篇
  2005年   39篇
  2004年   33篇
  2003年   44篇
  2002年   37篇
  2001年   20篇
  2000年   34篇
  1999年   39篇
  1998年   42篇
  1997年   57篇
  1996年   49篇
  1995年   40篇
  1994年   36篇
  1993年   43篇
  1992年   33篇
  1991年   15篇
  1990年   26篇
  1989年   29篇
  1988年   26篇
  1987年   23篇
  1986年   11篇
  1985年   18篇
  1984年   6篇
  1983年   7篇
  1982年   12篇
  1981年   12篇
  1980年   15篇
  1979年   6篇
  1978年   7篇
  1977年   9篇
  1976年   20篇
  1975年   12篇
排序方式: 共有2111条查询结果,搜索用时 31 毫秒
1.
2.
3.
Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence.  相似文献   
4.
5.
A survey of 2576 children aged two to nine years was carried out in Dhaka, Bangladesh, as part of a collaborative study to test the validity of a questionnaire (the Ten Questions) for screening severe childhood disabilities in community settings. Approximately 7% of the children were positive on the screen and this rate was slightly higher in boys than girls. The sensitivity, specificity and negative predictive value of the Ten Questions were perfect or nearly perfect for severe and moderate (serious) disabilities. The positive predictive value was only 22% for serious disabilities, but 70% of children classified as false positives were found to have mild disabilities or other conditions (such as ear infections) for which early detection and treatment could be beneficial. No major age or gender differences in the validity of the questionnaire were apparent, but this finding needs additional study and confirmation with studies based on larger samples. In general, the results indicate that the Ten Questions is a valid tool for screening serious disabilities in children and can potentially improve the efficiency of health services by reducing the number of children requiring attention from professionals. Future studies using the Ten Questions should foster greater attention to the dimensions of childhood disability as a public health problem in the less developed world.  相似文献   
6.
Defecography in multiple sclerosis patients with severe constipation   总被引:3,自引:0,他引:3  
Gill  KP; Chia  YW; Henry  MM; Shorvon  PJ 《Radiology》1994,191(2):553
  相似文献   
7.
8.
9.
OBJECTIVES. This study evaluated the effectiveness of a community coalition to prevent severe injuries to children in Central Harlem, New York, NY. It was hypothesized that injury incidence rates would decline during the intervention (1989 through 1991) relative to preintervention years (1983 through 1988); that the decline would be greatest for the targeted age group (5 through 16 years) and targeted injury causes (traffic accidents, assaults, firearms, outdoor falls); and that the decline would occur in the intervention community rather than a control community. METHODS. Surveillance of injuries that result in hospitalization and/or death among children in the two communities has been under way since 1983. Data from this surveillance were used to test whether the incidence of severe injury declined during the intervention; other temporal variations were controlled by Poisson regression. RESULTS. The incidence of injury among school-aged children in central Harlem declined during the intervention. The decline was specific to the targeted age group and targeted causes. A nonspecific decline also occurred in the control community. CONCLUSIONS. The declining incidence rate in Central Harlem is consistent with a favorable program effect, but additional investigation of possible secular trend or spillover effects is needed.  相似文献   
10.
Solitary bronchioloalveolar carcinoma: CT criteria   总被引:14,自引:0,他引:14  
The computed tomographic (CT) scans of 30 patients with solitary bronchioloalveolar carcinoma were reviewed. Common features at CT included the peripheral or subpleural location of a pulmonary mass (25 cases), pseudocavitation (18 cases), heterogeneous attenuation (17 cases), irregular margins forming a star pattern (22 cases), and pleural tags (21 cases). Using these CT criteria, four independent observers attempted to identify cases of bronchioloalveolar carcinoma from a larger sample of lung cancers and benign lesions by categorizing a series of test cases into four probability categories. Although the bronchioloalveolar carcinomas were correctly ranked in the two highest probability categories 75% of the time (in 45 of 60 cases), there was considerable overlap with other lung lesions, particularly with adenocarcinoma and large cell undifferentiated carcinoma. However, even though the typical features of bronchioloalveolar carcinoma are not invariable or highly specific, they are characteristic enough to suggest the diagnosis.  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