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   1496篇
  免费   206篇
  国内免费   19篇
耳鼻咽喉   23篇
儿科学   60篇
妇产科学   22篇
基础医学   119篇
口腔科学   41篇
临床医学   218篇
内科学   323篇
皮肤病学   107篇
神经病学   64篇
特种医学   139篇
外科学   196篇
综合类   94篇
现状与发展   30篇
预防医学   105篇
眼科学   16篇
药学   45篇
中国医学   3篇
肿瘤学   116篇
  2024年   18篇
  2023年   182篇
  2022年   18篇
  2021年   19篇
  2020年   60篇
  2019年   28篇
  2018年   60篇
  2017年   56篇
  2016年   49篇
  2015年   62篇
  2014年   89篇
  2013年   72篇
  2012年   44篇
  2011年   47篇
  2010年   83篇
  2009年   95篇
  2008年   41篇
  2007年   68篇
  2006年   34篇
  2005年   31篇
  2004年   26篇
  2003年   26篇
  2002年   23篇
  2001年   20篇
  2000年   19篇
  1999年   33篇
  1998年   36篇
  1997年   50篇
  1996年   43篇
  1995年   36篇
  1994年   29篇
  1993年   35篇
  1992年   11篇
  1991年   8篇
  1990年   10篇
  1989年   26篇
  1988年   21篇
  1987年   15篇
  1986年   5篇
  1985年   15篇
  1984年   6篇
  1983年   3篇
  1982年   8篇
  1981年   10篇
  1980年   12篇
  1978年   5篇
  1977年   3篇
  1976年   13篇
  1975年   10篇
  1974年   3篇
排序方式: 共有1721条查询结果,搜索用时 15 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.
Many behavioral, immunological, and physiological consequences of brief maternal separation in bonnet (Macaca radiata) and pigtail monkeys (Macaca nemistrina) have been documented. However, the impact of social separation on plasma cortisol and growth hormone is unknown for these particular species. In the present study, the behavioral and endocrinological consequences of a 2-week maternal separation in socially housed infant bonnet and pigtail monkeys were followed. In seven pairs (separated and matched control) of bonnet and six pairs of pigtail infants, plasma was obtained under baseline, separated, and reunion conditions twice weekly for the duration of the study. Blood samples were obtained from both infants of the pair in approximately 10 min. Plasma total cortisol, free cortisol, and growth hormone were measured in these samples. Focal animal behavioral observations were made on all subjects twice daily throughout the study period. In both species, total cortisol and free cortisol rose immediately following maternal separation in comparison to the matched nonseparated controls and returned to basal levels (e.g., that of matched non-separted controls) following reunion with the mother. In contrast, plasma growth hormone rose only in the pigtail infants over a time course that peaked around the time of reunion. Multiple regression techniques indicated for the first week of separation, in the separated but not control subjects, that mean plasma free and total cortisol was positively related to distress behaviors (vocalization and postural slouch) observed during this week and negatively related to social behaviors (play and proximity to others) noted during the same period. In contrast, plasma growth hormone was related to both species and sex of the subjects but unrelated to behavioral variables. © 1995 John Wiley & Sons, Inc.  相似文献   
5.
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.
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   
10.
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