全文获取类型
收费全文 | 1094554篇 |
免费 | 93259篇 |
国内免费 | 17619篇 |
专业分类
耳鼻咽喉 | 14882篇 |
儿科学 | 27183篇 |
妇产科学 | 28305篇 |
基础医学 | 152862篇 |
口腔科学 | 29688篇 |
临床医学 | 107260篇 |
内科学 | 199897篇 |
皮肤病学 | 19469篇 |
神经病学 | 83904篇 |
特种医学 | 43977篇 |
外国民族医学 | 310篇 |
外科学 | 159756篇 |
综合类 | 61115篇 |
现状与发展 | 57篇 |
一般理论 | 288篇 |
预防医学 | 80847篇 |
眼科学 | 27518篇 |
药学 | 88741篇 |
194篇 | |
中国医学 | 14109篇 |
肿瘤学 | 65070篇 |
出版年
2022年 | 11023篇 |
2021年 | 16615篇 |
2020年 | 11825篇 |
2019年 | 12889篇 |
2018年 | 15552篇 |
2017年 | 13031篇 |
2016年 | 13349篇 |
2015年 | 18146篇 |
2014年 | 23839篇 |
2013年 | 27940篇 |
2012年 | 39250篇 |
2011年 | 42332篇 |
2010年 | 24768篇 |
2009年 | 21574篇 |
2008年 | 34192篇 |
2007年 | 36270篇 |
2006年 | 36195篇 |
2005年 | 35883篇 |
2004年 | 31139篇 |
2003年 | 29830篇 |
2002年 | 27768篇 |
2001年 | 41841篇 |
2000年 | 42873篇 |
1999年 | 37494篇 |
1998年 | 13073篇 |
1997年 | 12271篇 |
1996年 | 11441篇 |
1995年 | 10775篇 |
1994年 | 9991篇 |
1992年 | 29121篇 |
1991年 | 28211篇 |
1990年 | 27396篇 |
1989年 | 26273篇 |
1988年 | 24694篇 |
1987年 | 24159篇 |
1986年 | 22874篇 |
1985年 | 22030篇 |
1984年 | 16962篇 |
1983年 | 14449篇 |
1979年 | 17014篇 |
1978年 | 12222篇 |
1977年 | 10288篇 |
1976年 | 9420篇 |
1975年 | 10247篇 |
1974年 | 12754篇 |
1973年 | 12239篇 |
1972年 | 11651篇 |
1971年 | 10783篇 |
1970年 | 10306篇 |
1969年 | 9971篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
85.
目的:基于光学相干断层扫描血管成像(OCTA)技术探讨青少年儿童近视与视网膜表层微血管密度 及视网膜厚度的相关性。方法:横断面研究。共纳入2018年5─11月于四川大学华西医院眼科门 诊就诊的7~14岁青少年近视患者105例(193眼)。对所有受检者进行光学相干断层扫描(OCT)和 OCTA检查,量化分析黄斑中心凹视网膜厚度和各部位视网膜表层微血管密度。单因素方差分析比 较低、中、高度近视组各部位视网膜微血管密度及视网膜厚度的差异。采用Pearson相关系数探讨视 网膜厚度与各部位视网膜表层微血管密度的相关性。Spearman相关系数用于探讨等效球镜与中心凹、 旁中心凹视网膜表层微血管密度以及视网膜厚度的关系;分段多项式函数分析等效球镜度与外环及 直径6 mm完整视网膜表层微血管密度的关系。结果:旁中心凹、外环、直径6 mm完整区域视网膜 表层微血管密度在低、中、高度近视组间比较差异均具有统计学意义(F=11.651、14.499、14.232, 均P<0.001)。年龄与中心凹视网膜厚度之间有较弱正相关关系(r=0.187,P=0.011),与各部位微血管 密度均无相关性。等效球镜度与旁中心凹视网膜微血管密度有相关性(r=-0.301,P<0.001),与外环、 直径6 mm完整区域视网膜表层微血管密度呈曲线相关(r=-0.319,P<0.001;r=-0.307,P<0.001)。 但与中心凹视网膜表层微血管密度及视网膜厚度无显著相关性。此外,中心凹处视网膜厚度与微血 管密度呈正相关(r=0.691,P<0.001),与其余部位微血管密度无相关性。结论:青少年近视程度数 与旁中心凹、外环及直径6 mm完整区域视网膜表层微血管密度呈负相关;中心凹处视网膜厚度与年 龄、微血管密度呈正相关。 相似文献
86.
F. Giovanardi F. Nudo Q. Lai M. Garofalo A. Consolo E. Choppin De Janvry G.A. Arroyo Murillo P. Ursi D. Stabile F. Melandro P.B. Berloco R. Pretagostini L. Poli 《Transplantation proceedings》2019,51(1):128-131
Background
Arterial vascular anomalies in patients undergoing kidney transplantation (KT) are correlated with a higher incidence of early surgical complications, potentially causing graft loss. Arterial reconstruction allows patients to overcome these surgical challenges, thus minimizing the risk of poor outcomes. The aim of the present study is to retrospectively investigate the safety and effectiveness of the multiple arterial reconstruction technique with a Teflon patch in case of an unavailable aortic patch: to do so, surgical complications, graft function, and patient survival were evaluated.Methods
During the period January 2009 to August 2016, 202 adult deceased-donor KTs were performed at our center. Group A (n = 27; reconstruction of multiple arteries) and Group B (n = 175; control group) were compared.Results
No differences were observed between the 2 groups in terms of early postoperative course, with no vascular complication observed in Group A. No vascular patch infections were reported, nor longer cold ischemia time rates. Similarly, long-term survival rates were similar between the 2 groups.Conclusions
The Teflon-patch arterial reconstruction technique appears to be safe and effective, with an acceptable balance of benefits and potential risks of using a prosthetic material. Studies based on larger series are needed to further validate this approach. 相似文献87.
Paul J. Devlin Brian W. McCrindle James K. Kirklin Eugene H. Blackstone William M. DeCampli Christopher A. Caldarone Ali Dodge-Khatami Pirooz Eghtesady James M. Meza Peter J. Gruber Kristine J. Guleserian Bahaaladin Alsoufi Linda M. Lambert James E. OBrien Erle H. Austin Jeffrey P. Jacobs Tara Karamlou 《The Journal of thoracic and cardiovascular surgery》2019,157(2):684-695.e8
Objective
Arch obstruction after the Norwood procedure is common and contributes to mortality. We determined the prevalence, associated factors, and practice variability of arch reintervention and assessed whether arch reintervention is associated with mortality.Methods
From 2005 to 2017, 593 neonates in the Congenital Heart Surgeons' Society Critical Left Heart Obstruction cohort underwent a Norwood procedure. Median follow-up was 3.7 years. Multivariable parametric models, including a modulated renewal analysis, were performed.Results
Of the 593 neonates, 146 (25%) underwent 218 reinterventions for arch obstruction after the Norwood procedure: catheter-based (n = 168) or surgical (n = 50) at a median age of 4.3 months (quartile 1-quartile 3, 2.6-5.7). Interdigitation of the distal aortic anastomosis was protective against arch reintervention. Development of ≥ moderate tricuspid valve regurgitation and right ventricular dysfunction at any point was associated with arch reintervention. Nonsignificant variables for arch reintervention included shunt type and preoperative aortic measurements. Surgical arch reintervention was protective against arch reintervention, but transcatheter reintervention was associated with increased reintervention. Arch reintervention was not associated with increased mortality. There was wide institutional variation in incidence of arch reintervention (range, 0-40 reinterventions per 100 years patient follow-up) and in preintervention gradient (range, 0-64 mm Hg).Conclusions
Interdigitation of the distal aortic anastomosis during the Norwood procedure decreased the risk of arch reintervention. Surgical arch reintervention is more definitive than transcatheter. Arch reintervention after the Norwood procedure is not associated with increased mortality. Serial surveillance for arch obstruction, integrated with changes in right ventricular function and tricuspid valve regurgitation, is recommended after the Norwood procedure to improve outcomes. 相似文献88.
To evaluate the anthropometric indexes in subjects with varicocele compared to controls and the incidence of varicocele in different body mass index (BMI) groups for the purpose of exploring the association between varicocele and anthropometric indexes. A comprehensive literature search was conducted by using PubMed, MEDLINE, EMBASE databases and Cochrane Library up to February 2019. A systematic review and meta‐analysis was conducted by STATA, and Newcastle–Ottawa Scale was utilised for assessing risk of bias. Ultimately, 13 articles containing seven case–control studies and six cross‐sectional studies with 1,385,630 subjects were involved in our study. Pooled results demonstrated that varicocele patients had a lower BMI (WMD = ?0.77, 95% CI = ?1.03 to ?0.51) and a higher height than nonvaricocele participants, especially in grade 3 varicocele patients. Subgroup analyses showed that normal BMI individuals had a higher risk of varicocele than obese or overweight individuals and a lower risk than underweight individuals. In conclusion, this study indicates that varicocele patients have a lower BMI and a higher height than nonvaricocele participants. Moreover, men with excess bodyweight have a lower incidence of varicocele compared to normal weight or underweight people. That is to say, high BMI and adiposity protect against varicocele and high BMI is associated with a decreased risk of varicocele. 相似文献
89.
90.