全文获取类型
收费全文 | 8262篇 |
免费 | 768篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 65篇 |
儿科学 | 359篇 |
妇产科学 | 184篇 |
基础医学 | 1017篇 |
口腔科学 | 157篇 |
临床医学 | 1448篇 |
内科学 | 1450篇 |
皮肤病学 | 122篇 |
神经病学 | 621篇 |
特种医学 | 290篇 |
外科学 | 818篇 |
综合类 | 315篇 |
一般理论 | 5篇 |
预防医学 | 1019篇 |
眼科学 | 122篇 |
药学 | 563篇 |
中国医学 | 3篇 |
肿瘤学 | 501篇 |
出版年
2023年 | 39篇 |
2022年 | 73篇 |
2021年 | 202篇 |
2020年 | 120篇 |
2019年 | 185篇 |
2018年 | 202篇 |
2017年 | 157篇 |
2016年 | 160篇 |
2015年 | 165篇 |
2014年 | 224篇 |
2013年 | 398篇 |
2012年 | 565篇 |
2011年 | 496篇 |
2010年 | 304篇 |
2009年 | 252篇 |
2008年 | 501篇 |
2007年 | 514篇 |
2006年 | 481篇 |
2005年 | 513篇 |
2004年 | 481篇 |
2003年 | 449篇 |
2002年 | 454篇 |
2001年 | 127篇 |
2000年 | 128篇 |
1999年 | 137篇 |
1998年 | 99篇 |
1997年 | 70篇 |
1996年 | 81篇 |
1995年 | 75篇 |
1994年 | 55篇 |
1993年 | 54篇 |
1992年 | 77篇 |
1991年 | 81篇 |
1990年 | 82篇 |
1989年 | 75篇 |
1988年 | 72篇 |
1987年 | 57篇 |
1986年 | 59篇 |
1985年 | 47篇 |
1984年 | 61篇 |
1983年 | 53篇 |
1982年 | 34篇 |
1981年 | 33篇 |
1980年 | 34篇 |
1979年 | 46篇 |
1978年 | 36篇 |
1972年 | 34篇 |
1971年 | 45篇 |
1969年 | 32篇 |
1966年 | 32篇 |
排序方式: 共有9059条查询结果,搜索用时 31 毫秒
1.
2.
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3.
5.
6.
7.
Guerard W. Byrne Johannes M. Schirmer David N. Fass Sumeet S. Teotia Walter K. Kremers Hui Xu Bashoo Naziruddin Henry D. Tazelaar John S. Logan Christopher G. A. McGregor 《American journal of transplantation》2005,5(5):1011-1020
Microvascular thrombosis is a prominent feature in cardiac delayed xenograft rejection (DXR). We investigated the impact of warfarin or low-molecular-weight heparin (LMWH) anti-coagulation on xenograft function using a heterotopic pig-to-primate model. Donor hearts were from CD46 transgenic pigs and baboon immunosuppression included tacrolimus, sirolimus, anti-CD20 and TPC, an alpha-galactosyl-polyethylene glycol conjugate. Three groups of animals were studied. Group 1 (n = 9) was treated with warfarin, Group 2 (n = 13) with LMWH and Group 3, received no anti-coagulant drugs. The median duration of xenograft function was 20 days (range 3-62 days), 18 days (range 5-109 days) and 15 days (range 4-53 days) in Groups 1 to 3 respectively. Anti-coagulation achieved the targeted international normalized prothrombin ratio (INR) and anti-factor Xa levels consistent with effective in vivo therapy yet, no significant impact on median xenograft function was observed. At rejection, a similar histology of thrombosis and ischemia was apparent in each group and the levels of fibrin deposition and platelet thrombi in rejected tissue was the same. Anti-coagulation with warfarin or LMWH did not have a significant impact on the onset of DXR and microvascular thrombosis. However, a role for specific anti-coagulant strategies to achieve long-term xenograft function cannot be excluded. 相似文献
8.
9.
Diabetic neuropathic foot ulcers and amputation 总被引:2,自引:0,他引:2
David J. Margolis MD PhD ; Lynne Allen-Taylor PhD ; Ole Hoffstad MA ; Jesse A. Berlin ScD 《Wound repair and regeneration》2005,13(3):230-236
A neuropathic foot ulcer is a severe complication of diabetes that can result in a more severe complication, a lower extremity amputation. We conducted a cohort study of 24,616 individuals with a diabetic neuropathic foot ulcer treated within a multicenter wound care network. A total of 1653 (6.7%) individuals had an amputation and 46.3% of these amputations were of a toe or ray (minor amputation). In the more than 10-year follow-up period that we studied, the percentage of those who had an amputation varied between 5.6% and 8.4%. Of those who had an amputation, the percentage that had a minor amputation increased over time from 4.0% in the earliest years to more than 60% in the later years of observation. The single most important determinant of amputation was the observation of fascia, tendon, and bone at the initial assessment. In conclusion, about 7% of those with a diabetic neuropathic foot ulcer will have an amputation and in the past 10 years there has been a remarkable increase in the number of minor as compared to major amputations. 相似文献
10.
M J Hershman R I Swift D T Reilly W A Logan J M Sackier H Gompertz J Horner N W Baker C B Wood 《Journal of the Royal College of Surgeons of Edinburgh》1990,35(1):29-32
This study compared one dose of cefotetan with three doses of piperacillin as prophylaxis against wound infection in 153 patients undergoing elective colorectal surgery. The patients were randomized into two groups: the first received 2 g cefotetan intravenously with induction of anaesthesia (n = 75), and the second received three doses of 2 g piperacillin (n = 78). Wound infection was defined as the presence of an abscess or discharging pus from the wound. In the cefotetan group there were 14 (19%) wound infections and 13 (17%) in the piperacillin group. There were three septic deaths, one in the cefotetan group and two in the piperacillin group. Both groups were comparable with regard to age, sex, nature of pathology and pre- and perioperative risk factors. No significant haematological or biochemical abnormalities were detected. The only adverse reaction was one patient who had an allergic reaction (rash) to piperacillin. These data suggest that single-dose cefotetan is as effective as triple-dose piperacillin in prophylaxis against infection in elective colorectal surgery. 相似文献