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   1720篇
  免费   68篇
  国内免费   5篇
耳鼻咽喉   16篇
儿科学   90篇
妇产科学   51篇
基础医学   154篇
口腔科学   37篇
临床医学   143篇
内科学   471篇
皮肤病学   38篇
神经病学   58篇
特种医学   268篇
外科学   200篇
综合类   62篇
一般理论   1篇
预防医学   73篇
眼科学   8篇
药学   75篇
中国医学   1篇
肿瘤学   47篇
  2018年   11篇
  2017年   12篇
  2015年   12篇
  2014年   16篇
  2013年   27篇
  2012年   17篇
  2011年   12篇
  2010年   40篇
  2009年   46篇
  2008年   24篇
  2007年   16篇
  2006年   20篇
  2005年   12篇
  2004年   12篇
  2003年   13篇
  2001年   18篇
  2000年   10篇
  1999年   16篇
  1998年   57篇
  1997年   85篇
  1996年   68篇
  1995年   53篇
  1994年   76篇
  1993年   67篇
  1992年   33篇
  1991年   30篇
  1990年   25篇
  1989年   52篇
  1988年   50篇
  1987年   42篇
  1986年   52篇
  1985年   44篇
  1984年   26篇
  1983年   32篇
  1982年   33篇
  1981年   25篇
  1980年   33篇
  1979年   18篇
  1978年   21篇
  1977年   26篇
  1976年   19篇
  1975年   25篇
  1959年   42篇
  1958年   57篇
  1957年   46篇
  1956年   47篇
  1955年   41篇
  1954年   54篇
  1949年   26篇
  1948年   38篇
排序方式: 共有1793条查询结果,搜索用时 937 毫秒
1.
2.
3.
Conventional risk factors have very low predictive power in identifying haemodialysis patients at high risk of vascular accidents. A role for apolipoprotein E isotypes was looked for in a small, but rigorously defined, cohort of longterm haemodialysis patients. In individuals with high vascular risk, as identified by higher common carotid intima/media thickness, we found an excess of apolipoprotein E4 alleles. This preliminary result requires confirmation in large patient cohorts.   相似文献   
4.
5.
Forty-two cases of haemangiopericytoma were studied retrospectively using immunohistochemical staining with PC10, a monoclonal antibody to PCNA. The percentage of tumour cells with positive staining for PCNA was found to correlate well with histological grading. Clinical follow-up data were available in 25 adults and showed no known deaths in 11 cases with a low proportion (less than 14%) of positive cells. Out of 14 cases with a high number (greater than or equal to 14%) of positive cells, seven patients are known to have died, two had metastases, and in a further two there have been multiple recurrences of tumour. DNA flow cytometry was performed on 26 cases but this showed no correlation with PC10 staining or clinical outcome. Staining with PC10 may be of particular value in the identification of patients at greatest risk of rapid tumour metastasis and early death.  相似文献   
6.
7.
Hodgkin disease: CT of the thymus   总被引:2,自引:0,他引:2  
Heron  CW; Husband  JE; Williams  MP 《Radiology》1988,167(3):647-651
The computed tomography (CT) scans in two groups of patients with Hodgkin disease were reviewed to determine the frequency of thymic enlargement. In 50 CT scans from 50 patients with evidence of thoracic disease on CT scans who were examined for primary staging, the thymus was enlarged in 15 of 50 (30%). Fifty CT scans were obtained from 44 patients at the time of 50 separate episodes of known or suspected relapse. Relapse occurred in the mediastinum in 12 episodes, lung parenchyma in five, and both sites in one. Thymic enlargement thought to be due to involvement by disease was present in seven of 18 (38%). Mediastinal disease was associated with thymic enlargement in all but one patient in whom a thymic cyst developed after radiation therapy. Differentiation of thymic enlargement from enlarged superior mediastinal lymph nodes was easily made in all but two patients. Thymic enlargement in the absence of lymph node enlargement may indicate a different disease, since isolated Hodgkin disease of the thymus is uncommon. Primary thymic tumor should be considered initially, whereas after treatment, rebound hyperplasia of the thymus may be the cause of enlargement.  相似文献   
8.
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   
9.
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