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   116989篇
  免费   10794篇
  国内免费   7919篇
耳鼻咽喉   963篇
儿科学   1409篇
妇产科学   1312篇
基础医学   13292篇
口腔科学   1995篇
临床医学   14672篇
内科学   16621篇
皮肤病学   1318篇
神经病学   6040篇
特种医学   4534篇
外国民族医学   52篇
外科学   12979篇
综合类   21695篇
现状与发展   35篇
一般理论   6篇
预防医学   8324篇
眼科学   2641篇
药学   12154篇
  128篇
中国医学   6872篇
肿瘤学   8660篇
  2024年   326篇
  2023年   1637篇
  2022年   3879篇
  2021年   5807篇
  2020年   4357篇
  2019年   3713篇
  2018年   3829篇
  2017年   3479篇
  2016年   3371篇
  2015年   5370篇
  2014年   6621篇
  2013年   6395篇
  2012年   9273篇
  2011年   10362篇
  2010年   6812篇
  2009年   5388篇
  2008年   6776篇
  2007年   6504篇
  2006年   6372篇
  2005年   5729篇
  2004年   3988篇
  2003年   3817篇
  2002年   3067篇
  2001年   2458篇
  2000年   2405篇
  1999年   2369篇
  1998年   1476篇
  1997年   1535篇
  1996年   1211篇
  1995年   1083篇
  1994年   915篇
  1993年   595篇
  1992年   716篇
  1991年   643篇
  1990年   554篇
  1989年   490篇
  1988年   404篇
  1987年   349篇
  1986年   315篇
  1985年   240篇
  1984年   178篇
  1983年   122篇
  1982年   89篇
  1981年   103篇
  1980年   76篇
  1979年   83篇
  1978年   47篇
  1975年   39篇
  1974年   39篇
  1973年   36篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
32.
33.
TL1A is a TNF‐like cytokine which has been shown to co‐stimulate TH1 and TH17 responses during chronic inflammation. The expression of this novel cytokine has been investigated in inflammatory disorders like rheumatoid arthritis and inflammatory bowel disease, but little is known about expression and induction in psoriasis. Indeed, the pathogenesis in psoriasis is still not fully understood and it is speculated that cytokines other than TNF‐α are important in subsets of patients. Also, for patients with severe disease that are treated with systemic anti‐TNF‐α blockade, novel candidates to be used as disease and response biomarkers are of high interest. Here, we demonstrate TL1A expression in biopsies from psoriatic lesions. Also, we investigated spontaneous and induced TL1A secretion from PBMCs and blood levels from a cohort of psoriasis patients. Here, increased spontaneous secretion from PBMCs was observed as compared to healthy controls and a small subset of patients had highly elevated TL1A in the blood. Interestingly, activation of PBMCs with various cytokines showed a decreased sensitivity for TL1A activation in psoriasis patients compared to healthy controls.TL1A levels in blood and biopsies could not be correlated with disease activity with this patient cohort. Thus, additional large‐scale studies are warranted to investigate TL1A as a biomarker.  相似文献   
34.
35.
36.
随着腔镜技术的进一步发展以及微创理念应用于结直肠外科疾病的诊治中,结直肠相关疾病的诊治发生了翻天覆地的变化。由传统的经腹手术到腹腔镜手术、经自然腔道手术,再到经自然腔道取标本手术(NOSES),结直肠疾病的外科诊治在微创领域取得了巨大成果。NOSES技术是目前结直肠外科在微创领域前沿的手术方式之一,它通过经直肠、阴道取标本来避免了腹壁的辅助取标本切口,从而将结直肠外科手术进一步微创化。NOSES技术集传统腹腔镜手术的优势与现代微创外科的理念于一体,它在确保手术效果的基础上集中体现了微创、加速康复外科、功能外科、"无疤"等理念的特点。本文主要就国内外各中心开展NOSES技术在结直肠外科诊治开展中的相关经验、心得和体会进行综述。  相似文献   
37.
38.
By means of the ultrasonic surface impact (amplitude of 30 μm, strike number of 48,000 times/mm2), nanograins have been achieved in the surfaces of both Ti6Al4V(TC4) and Ti3Zr2Sn3Mo25Nb(TLM) titanium alloys, mainly because of the dislocation motion. Many mechanical properties are improved, such as hardness, residual stress, and roughness. The rotating–bending fatigue limits of TC4 and TLM subjected to ultrasonic impact are improved by 13.1% and 23.7%, separately. Because of the bending fatigue behavior, which is sensitive to the surface condition, cracks usually initiate from the surface defects under high stress amplitude. By means of an ultrasonic impact tip with the size of 8 mm, most of the inner cracks present at the zone with a depth range of 100~250 μm in the high life region. The inner crack core to TC4 usually appears as a deformed long and narrow α-phase, while the cracks in TLM specimens prefer to initiate at the triple grain boundary junctions. This zone crosses the grain refined layer and the deformed coarse grain layer. With the gradient change of elastic parameters, the model shows an increase of normal stress at this zone. Combined with the loss of plasticity and toughness, it is easy to understand these fatigue behaviors.  相似文献   
39.
40.
The analysis of quality of life (QoL) data can be challenging due to the skewness of responses and the presence of missing data. In this paper, we propose a new weighted quantile regression method for estimating the conditional quantiles of QoL data with responses missing at random. The proposed method makes use of the correlation information within the same subject from an auxiliary mean regression model to enhance the estimation efficiency and takes into account of missing data mechanism. The asymptotic properties of the proposed estimator have been studied and simulations are also conducted to evaluate the performance of the proposed estimator. The proposed method has also been applied to the analysis of the QoL data from a clinical trial on early breast cancer, which motivated this study.  相似文献   
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