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   1304150篇
  免费   99289篇
  国内免费   2508篇
耳鼻咽喉   16684篇
儿科学   42037篇
妇产科学   36065篇
基础医学   194100篇
口腔科学   35482篇
临床医学   121545篇
内科学   257541篇
皮肤病学   27936篇
神经病学   105540篇
特种医学   48281篇
外国民族医学   267篇
外科学   184208篇
综合类   27824篇
现状与发展   4篇
一般理论   569篇
预防医学   106890篇
眼科学   28630篇
药学   96088篇
  14篇
中国医学   2970篇
肿瘤学   73272篇
  2021年   11024篇
  2019年   11073篇
  2018年   14722篇
  2017年   11371篇
  2016年   12368篇
  2015年   14415篇
  2014年   19718篇
  2013年   29558篇
  2012年   40311篇
  2011年   42755篇
  2010年   24726篇
  2009年   23771篇
  2008年   40077篇
  2007年   42701篇
  2006年   42101篇
  2005年   41136篇
  2004年   39407篇
  2003年   37550篇
  2002年   36280篇
  2001年   57087篇
  2000年   58052篇
  1999年   49042篇
  1998年   13791篇
  1997年   12512篇
  1996年   12954篇
  1995年   12153篇
  1994年   11329篇
  1992年   38717篇
  1991年   38110篇
  1990年   36880篇
  1989年   35698篇
  1988年   33050篇
  1987年   32361篇
  1986年   30822篇
  1985年   29051篇
  1984年   22151篇
  1983年   19361篇
  1982年   11454篇
  1979年   21128篇
  1978年   15500篇
  1977年   12884篇
  1976年   11925篇
  1975年   12884篇
  1974年   15686篇
  1973年   15458篇
  1972年   14608篇
  1971年   13646篇
  1970年   12869篇
  1969年   12145篇
  1968年   11304篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  相似文献   
44.
45.
46.
47.
48.
Prevalence of osteoporosis is more than 50% in older adults, yet current clinical methods for diagnosis that rely on areal bone mineral density (aBMD) fail to detect most individuals who have a fragility fracture. Bone fragility can manifest in different forms, and a “one-size-fits-all” approach to diagnosis and management of osteoporosis may not be suitable. High-resolution peripheral quantitative computed tomography (HR-pQCT) provides additive information by capturing information about volumetric density and microarchitecture, but interpretation is challenging because of the complex interactions between the numerous properties measured. In this study, we propose that there are common combinations of bone properties, referred to as phenotypes, that are predisposed to different levels of fracture risk. Using HR-pQCT data from a multinational cohort (n = 5873, 71% female) between 40 and 96 years of age, we employed fuzzy c-means clustering, an unsupervised machine-learning method, to identify phenotypes of bone microarchitecture. Three clusters were identified, and using partial correlation analysis of HR-pQCT parameters, we characterized the clusters as low density, low volume, and healthy bone phenotypes. Most males were associated with the healthy bone phenotype, whereas females were more often associated with the low volume or low density bone phenotypes. Each phenotype had a significantly different cumulative hazard of major osteoporotic fracture (MOF) and of any incident osteoporotic fracture (p < 0.05). After adjustment for covariates (cohort, sex, and age), the low density followed by the low volume phenotype had the highest association with MOF (hazard ratio = 2.96 and 2.35, respectively), and significant associations were maintained when additionally adjusted for femoral neck aBMD (hazard ratio = 1.69 and 1.90, respectively). Further, within each phenotype, different imaging biomarkers of fracture were identified. These findings suggest that osteoporotic fracture risk is associated with bone phenotypes that capture key features of bone deterioration that are not distinguishable by aBMD. © 2021 American Society for Bone and Mineral Research (ASBMR).  相似文献   
49.
Context: Treatment of primary spinal syringomyelia is still controversial. Among others, shunting syrinx fluid to the subarachnoid, peritoneal or pleural space has been utilized with varying success. Shunt obstruction, migration, and infection represent the most common complications of these procedures.

Findings: The authors present the case of an 81-year-old woman who developed an unusual neurological deterioration resembling a subacute posttraumatic ascending myelopathy (SPAM) after the insertion of a syringosubarachnoid shunt for the treatment of slow-growing D10 syringomyelia.

Conclusion/Clinical Relevance: To date, no cases of SPAM secondary to the insertion of a syringosubarachnoid shunt for the treatment of syringomyelia have been reported. The potential pathogenesis related to this phenomenon is discussed.  相似文献   
50.
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