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   2068802篇
  免费   151271篇
  国内免费   4231篇
耳鼻咽喉   27152篇
儿科学   68218篇
妇产科学   56398篇
基础医学   302352篇
口腔科学   60157篇
临床医学   184628篇
内科学   399986篇
皮肤病学   47694篇
神经病学   158107篇
特种医学   77191篇
外国民族医学   304篇
外科学   313203篇
综合类   45551篇
现状与发展   4篇
一般理论   631篇
预防医学   154893篇
眼科学   49421篇
药学   153336篇
  7篇
中国医学   5108篇
肿瘤学   119963篇
  2019年   15944篇
  2018年   23294篇
  2017年   17705篇
  2016年   19447篇
  2015年   22057篇
  2014年   30432篇
  2013年   44896篇
  2012年   61975篇
  2011年   65739篇
  2010年   38793篇
  2009年   36352篇
  2008年   61400篇
  2007年   65446篇
  2006年   66155篇
  2005年   63033篇
  2004年   61049篇
  2003年   57994篇
  2002年   56189篇
  2001年   107280篇
  2000年   109766篇
  1999年   90712篇
  1998年   23652篇
  1997年   20724篇
  1996年   21051篇
  1995年   20061篇
  1994年   18444篇
  1993年   17083篇
  1992年   68474篇
  1991年   66820篇
  1990年   64621篇
  1989年   62124篇
  1988年   56709篇
  1987年   55526篇
  1986年   52120篇
  1985年   49593篇
  1984年   36462篇
  1983年   31066篇
  1982年   17389篇
  1979年   32761篇
  1978年   22953篇
  1977年   19466篇
  1976年   18329篇
  1975年   19661篇
  1974年   23762篇
  1973年   22714篇
  1972年   21319篇
  1971年   19878篇
  1970年   18475篇
  1969年   17384篇
  1968年   16308篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.

Purpose

Chest wall pain is an uncommon but bothersome late complication following lung stereotactic body radiation therapy. Despite numerous studies investigating predictors of chest wall pain, no clear consensus has been established for a chest wall constraint. The aim of our study was to investigate factors related to chest wall pain in a homogeneous group of patients treated at our institution.

Patients and methods

All 122 patients were treated with the same stereotactic body radiation therapy regimen of 48 Gy in three fractions, seen for at least 6 months of follow-up, and planned with heterogeneity correction. Chest wall pain was scored according to the Common Terminology Criteria for Adverse Events classification v3.0. Patient (age, sex, diabetes, osteoporosis), tumour (planning target volume, volume of the overlapping region between planning target volume and chest wall) and chest wall dosimetric parameters (volumes receiving at least 30, 40, and 50 Gy, the minimal doses received by the highest irradiated 1, 2, and 5 cm3, and maximum dose) were collected. The correlation between chest wall pain (grade 2 or higher) and the different parameters was evaluated using univariate and multivariate logistic regression.

Results

Median follow-up was 18 months (range: 6–56 months). Twelve patients out of 122 developed chest wall pain of any grade (seven with grade 1, three with grade 2 and two with grade 3 pain). In univariate analysis, only the volume receiving 30 Gy or more (P = 0.034) and the volume of the overlapping region between the planning target volume and chest wall (P = 0.038) significantly predicted chest wall pain, but these variables were later proved non-significant in multivariate regression.

Conclusion

Our analysis could not find any correlation between the studied parameters and chest wall pain. Considering our present study and the wide range of differing results from the literature, a reasonable conclusion is that a constraint for chest wall pain is yet to be defined.  相似文献   
92.
To evaluate the changes in alveolar contour after guided bone regeneration (GBR) with two different combinations of biomaterials in dehiscence defects arou  相似文献   
93.
94.
95.
96.
97.
Individuals with sudden unilateral deafness offer a unique opportunity to study plasticity of the binaural auditory system in adult humans. Stimulation of the intact ear results in increased activity in the auditory cortex. However, there are no reports of changes at sub-cortical levels in humans. Therefore, the aim of the present study was to investigate changes in sub-cortical activity immediately before and after the onset of surgically induced unilateral deafness in adult humans. Click-evoked auditory brainstem responses (ABRs) to stimulation of the healthy ear were recorded from ten adults during the course of translabyrinthine surgery for the removal of a unilateral acoustic neuroma. This surgical technique always results in abrupt deafferentation of the affected ear. The results revealed a rapid (within minutes) reduction in latency of wave V (mean pre = 6.55 ms; mean post = 6.15 ms; p < 0.001). A latency reduction was also observed for wave III (mean pre = 4.40 ms; mean post = 4.13 ms; p < 0.001). These reductions in response latency are consistent with functional changes including disinhibition or/and more rapid intra-cellular signalling affecting binaurally sensitive neurons in the central auditory system. The results are highly relevant for improved understanding of putative physiological mechanisms underlying perceptual disorders such as tinnitus and hyperacusis.  相似文献   
98.
99.
DNA methylation at CpG dinucleotides is an important epigenetic regulator common to virtually all mammalian cell types, but recent evidence indicates that during early postnatal development neuronal genomes also accumulate uniquely high levels of two alternative forms of methylation, non-CpG methylation and hydroxymethylation. Here we discuss the distinct landscape of DNA methylation in neurons, how it is established, and how it might affect the binding and function of protein readers of DNA methylation. We review studies of one critical reader of DNA methylation in the brain, the Rett syndrome protein methyl CpG-binding protein 2 (MeCP2), and discuss how differential binding affinity of MeCP2 for non-CpG and hydroxymethylation may affect the function of this methyl-binding protein in the nervous system.  相似文献   
100.
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