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   105284篇
  免费   6882篇
  国内免费   755篇
耳鼻咽喉   1215篇
儿科学   3296篇
妇产科学   2635篇
基础医学   14454篇
口腔科学   2306篇
临床医学   9048篇
内科学   22555篇
皮肤病学   2264篇
神经病学   10190篇
特种医学   3935篇
外国民族医学   23篇
外科学   14332篇
综合类   1704篇
一般理论   60篇
预防医学   6345篇
眼科学   1696篇
药学   8404篇
  3篇
中国医学   521篇
肿瘤学   7935篇
  2023年   435篇
  2022年   914篇
  2021年   1959篇
  2020年   1330篇
  2019年   1857篇
  2018年   2283篇
  2017年   1781篇
  2016年   1902篇
  2015年   2192篇
  2014年   2858篇
  2013年   4200篇
  2012年   5683篇
  2011年   5840篇
  2010年   3788篇
  2009年   3321篇
  2008年   5139篇
  2007年   5362篇
  2006年   5137篇
  2005年   4910篇
  2004年   5181篇
  2003年   4991篇
  2002年   5011篇
  2001年   3770篇
  2000年   3688篇
  1999年   3051篇
  1998年   1261篇
  1997年   991篇
  1996年   897篇
  1995年   878篇
  1994年   742篇
  1993年   736篇
  1992年   1812篇
  1991年   1799篇
  1990年   1526篇
  1989年   1457篇
  1988年   1347篇
  1987年   1195篇
  1986年   1190篇
  1985年   1057篇
  1984年   788篇
  1983年   723篇
  1982年   483篇
  1981年   404篇
  1979年   593篇
  1978年   429篇
  1975年   441篇
  1974年   500篇
  1973年   470篇
  1972年   435篇
  1971年   401篇
排序方式: 共有10000条查询结果,搜索用时 843 毫秒
1.
Purpose: To use polymerase chain reaction (PCR) and Goldmann-Witmer coefficient (GWC) calculation to diagnose infectious uveitis.

Methods: Prospective cross-sectional study.

Results: Twenty-seven of 106 patients had positive PCR and/or GWC results on aqueous humor (AH) sampling and 15 of 27 (55.6%) were HIV-positive. Patients with non-anterior uveitis (NAU) were more likely to be HIV+ (p = 0.005). More than 1 possible pathogen was identified in 9 of 27 patients of whom 7 were HIV+. The final clinical diagnosis was discordant with AH findings in 9 of 27 cases. A positive EBV PCR result was associated with a discordant diagnosis (p = 0.001). All cases of herpetic anterior uveitis (42.9% HIV+) tested PCR-/GWC+ while all cases of herpetic NAU tested PCR+/GWC- (83.3% HIV+). All rubella virus cases were PCR+/GWC+.

Conclusion: PCR is useful to diagnose herpetic NAU in HIV+ patients while GWC is useful to diagnose herpetic anterior uveitis.  相似文献   

2.
3.
4.
5.
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   
6.
7.
8.
ABSTRACT

Purpose

To investigate the expression of IL-11 and its receptor IL-11Rα and to quantify density of CD163+ M2 macrophages in proliferative diabetic retinopathy (PDR).  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