全文获取类型
| 收费全文 | 1373314篇 |
| 免费 | 122235篇 |
| 国内免费 | 2671篇 |
专业分类
| 耳鼻咽喉 | 18674篇 |
| 儿科学 | 43935篇 |
| 妇产科学 | 37665篇 |
| 基础医学 | 195233篇 |
| 口腔科学 | 39826篇 |
| 临床医学 | 143506篇 |
| 内科学 | 274411篇 |
| 皮肤病学 | 30890篇 |
| 神经病学 | 115266篇 |
| 特种医学 | 50535篇 |
| 外国民族医学 | 265篇 |
| 外科学 | 196701篇 |
| 综合类 | 25957篇 |
| 现状与发展 | 42篇 |
| 一般理论 | 578篇 |
| 预防医学 | 118247篇 |
| 眼科学 | 30395篇 |
| 药学 | 95034篇 |
| 7篇 | |
| 中国医学 | 2100篇 |
| 肿瘤学 | 78953篇 |
出版年
| 2021年 | 12654篇 |
| 2019年 | 12449篇 |
| 2018年 | 20435篇 |
| 2017年 | 17535篇 |
| 2016年 | 18995篇 |
| 2015年 | 20871篇 |
| 2014年 | 28285篇 |
| 2013年 | 39332篇 |
| 2012年 | 42505篇 |
| 2011年 | 44807篇 |
| 2010年 | 30095篇 |
| 2009年 | 31226篇 |
| 2008年 | 42197篇 |
| 2007年 | 43861篇 |
| 2006年 | 44422篇 |
| 2005年 | 42219篇 |
| 2004年 | 39933篇 |
| 2003年 | 38006篇 |
| 2002年 | 36632篇 |
| 2001年 | 57877篇 |
| 2000年 | 58281篇 |
| 1999年 | 49828篇 |
| 1998年 | 15435篇 |
| 1997年 | 14059篇 |
| 1996年 | 14487篇 |
| 1995年 | 13500篇 |
| 1994年 | 12108篇 |
| 1993年 | 11289篇 |
| 1992年 | 39001篇 |
| 1991年 | 38361篇 |
| 1990年 | 37009篇 |
| 1989年 | 35837篇 |
| 1988年 | 33226篇 |
| 1987年 | 32478篇 |
| 1986年 | 30920篇 |
| 1985年 | 29147篇 |
| 1984年 | 22250篇 |
| 1983年 | 19499篇 |
| 1982年 | 11612篇 |
| 1979年 | 21045篇 |
| 1978年 | 15560篇 |
| 1977年 | 12929篇 |
| 1976年 | 11964篇 |
| 1975年 | 12912篇 |
| 1974年 | 15712篇 |
| 1973年 | 15459篇 |
| 1972年 | 14633篇 |
| 1971年 | 13640篇 |
| 1970年 | 12881篇 |
| 1969年 | 12115篇 |
排序方式： 共有10000条查询结果，搜索用时 31 毫秒
1.
2.
3.
4.
5.
6.
7.
Conall T. Morgan Brigitte Mueller Varsha Thakur Vitor Guerra Callaghan Jull Luc Mertens Mark Friedberg Fraser Golding Mike Seed Steven E.S. Miner Edgar T. Jaeggi Cedric Manlhiot Lynne E. Nield 《The Canadian journal of cardiology》2019,35(4):453-461
Background
The purpose of the study was to evaluate the association between fetal echocardiographic measurements and the need for intervention (primary coarctation repair, staged coarctation repair, or catheter intervention) in prenatally diagnosed coarctation of the aorta.Methods
A single-centre retrospective cohort study (2005-2015) of 107 fetuses diagnosed with suspected coarctation of the aorta in the setting of an apex-forming left ventricle and antegrade flow across the mitral and aortic valves.Results
Median gestational age at diagnosis was 32 weeks (interquartile range, 23-35 weeks). Fifty-six (52%) did not require any neonatal intervention, 51 patients (48%) underwent a biventricular repair. In univariable analysis, an increase in ascending aorta (AAo) peak Doppler flow velocity (odds ratio [OR], 1.40 [95% confidence interval [CI], 1.05-1.91] per 20 cm/s; P = 0.03) was associated with intervention. No intervention was associated with larger isthmus size (OR, 0.23; P < 0.001), transverse arch diameter (OR, 0.23; P < 0.001), and aortic (OR, 0.72; P = 0.02), mitral (OR, 0.58; P = 0.001), and AAo (OR, 0.53; P < 0.001) z-scores. In multivariable analysis, higher peak AAo Doppler (OR, 2.51 [95% CI, 1.54-4.58] per 20 cm/s; P = 0.001) and younger gestational age at diagnosis (OR, 0.81 [95% CI, 0.70-0.93] per week; P = 0.005) were associated with intervention, whereas a higher AAo z-score (OR, 0.65 [95% CI, 0.43-0.94] per z; P = 0.029) and transverse arch dimension (OR, 0.44 [95% CI, 0.18-0.97]; P = 0.05) decreased the risk of intervention.Conclusions
In prenatally suspected coarctation, the variables associated with intervention comprised smaller AAo and transverse arch size, earlier gestational age at diagnosis, and the additional finding of a higher peak AAo Doppler. 相似文献8.
Adilson Cunha Ferreira Edward Araujo Júnior Wellington P. Martins João Francisco Jordão Antônio Hélio Oliani Simon E. Meagher 《The journal of maternal-fetal & neonatal medicine》2015,28(14):1706-1710
Objective: To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.Methods: In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.Results: The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI?=?66.4–86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI?=?70.0–80.8%) the scores of transmitted image were considered the same as the original.Conclusion: We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality. 相似文献
9.
10.
Xiaoxuan Liu Ameenat L. Solebo Livia Faes Sophie Beese Tasanee Braithwaite Matthew E. Round 《Ocular immunology and inflammation》2020,28(6):898-907
ABSTRACT