全文获取类型
收费全文 | 1857篇 |
免费 | 169篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 133篇 |
妇产科学 | 42篇 |
基础医学 | 269篇 |
口腔科学 | 40篇 |
临床医学 | 221篇 |
内科学 | 412篇 |
皮肤病学 | 36篇 |
神经病学 | 125篇 |
特种医学 | 102篇 |
外科学 | 195篇 |
综合类 | 62篇 |
预防医学 | 179篇 |
眼科学 | 17篇 |
药学 | 85篇 |
中国医学 | 4篇 |
肿瘤学 | 89篇 |
出版年
2022年 | 9篇 |
2021年 | 21篇 |
2020年 | 12篇 |
2019年 | 15篇 |
2018年 | 27篇 |
2017年 | 17篇 |
2016年 | 19篇 |
2015年 | 19篇 |
2014年 | 43篇 |
2013年 | 72篇 |
2012年 | 73篇 |
2011年 | 75篇 |
2010年 | 57篇 |
2009年 | 60篇 |
2008年 | 95篇 |
2007年 | 103篇 |
2006年 | 90篇 |
2005年 | 94篇 |
2004年 | 72篇 |
2003年 | 69篇 |
2002年 | 73篇 |
2001年 | 62篇 |
2000年 | 51篇 |
1999年 | 48篇 |
1998年 | 37篇 |
1997年 | 62篇 |
1996年 | 44篇 |
1995年 | 36篇 |
1994年 | 35篇 |
1993年 | 28篇 |
1992年 | 44篇 |
1991年 | 37篇 |
1990年 | 43篇 |
1989年 | 46篇 |
1988年 | 36篇 |
1987年 | 39篇 |
1986年 | 38篇 |
1985年 | 23篇 |
1984年 | 22篇 |
1983年 | 13篇 |
1981年 | 14篇 |
1980年 | 12篇 |
1979年 | 22篇 |
1978年 | 10篇 |
1977年 | 14篇 |
1976年 | 16篇 |
1975年 | 19篇 |
1974年 | 10篇 |
1972年 | 8篇 |
1970年 | 7篇 |
排序方式: 共有2027条查询结果,搜索用时 31 毫秒
1.
Maggie L. Westfal David C. Chang Cassandra M. Kelleher 《Journal of pediatric surgery》2019,54(1):140-144
Purpose
The purpose of this study was to evaluate trends in demographics and outcomes of pediatric breast cancer in a United States population-based cohort.Methods
The Surveillance, Epidemiology, and End Results (SEER) database was utilized to identify all pediatric patients with malignant breast tumors between 1973 and 2014. Analysis was performed using Stata Statistical Software version 13.1. Associations between categorical variables were made using X2 test. Log-rank test was used for univariate survival analysis. Kaplan–Meier analysis investigated five-year survival rates across several variables. Adjusted analysis was performed using a Cox Proportional-Hazards regression.Results
134 patients with breast malignancies were identified. Carcinoma was the most prevalent histology (48.5%), followed by fibroepithelial tumors (FETs) (35.1%), and sarcoma (14.2%). FETs were twice as common in black compared to nonblack patients (56.3% vs. 29.0%, p?<?0.01). Analyzing histology by stage revealed that 100% of FETs were early stage disease (p?<?0.0001). 46.7% of the tumors tested were ER/PR negative, more than twice as many compared to the published adult estimate of 20.0%. Unadjusted survival analysis revealed worse survival for patients with adenocarcinoma/sarcomas, advanced stage, and high grade disease, without a survival difference between races.Conclusion
Breast cancer remains a rare malignancy among pediatric patients. Although black patients were found to have more noncarcinomatous tumors with less advanced disease, this did not confer a survival advantage.Type of study
Retrospective cohort study.Level of evidence
Level III. 相似文献2.
V Aerra M Kuduvalli AN Moloto AK Srinivasan AD Grayson BM Fabri AY Oo 《Journal of cardiothoracic surgery》2006,1(1):6-5
Background
Atrial fibrillation can occur in up to 40% of patients undergoing coronary surgery. 相似文献3.
Paul Corcoran Michael J. Kelleher Helen S. Keeley Sinéad Byrne Ursula Burke Eileen Williamson 《Archives of Suicide Research》1997,3(1):65-74
This paper presents a statistical model constructed using logisticregression to identify those at high-risk of repeating parasuicide. Thesubjects in the study are Cork city residents who exhibited parasuicidalbehaviour between 1 January and 30 June 1995. Repetition of the behaviourwithin six months of the index episode distinguishes repeaters fromnon-repeaters. The model was designed so that it could be used bynon-clinicians and hence does not require information relating topsychiatric diagnosis or use of psychiatric services. The proportion ofsubjects correctly classified remained stable across a range of cut-pointprobabilities (mean = 86%, range: 83.9–87.5%). Using acut-point of 0.2, 96% of repeaters and 81% of non-repeaters were correctly classified. Using 0.45 led to the correct identification of81% of repeaters and 90% of non-repeaters. If these highlevels of sensitivity and specificity are maintained in validation tests onfuture cohorts in Cork city then the model could form the basis of anintervention programme designed to prevent the repetition of parasuicide. 相似文献
4.
J. O’Byrne S. Eustace M. M. Stephens M. N. M. R. Farahat G. Yanni R. Posten G. S. Panayi S. Sant R. Costello M. Barry J. Hassan C. Feighery B. Bresnihan A. Whelan F. Coakley A. M. de Paor R. B. Reilly E. B. Casey V. J. Tormey G. Kearns K. Gaffney P. J. Freyne M. Callaghan O. FitzGerald D. Veale E. O’Nuallain D. Reen D. Veale M. Farrell O. FitzGerald S. Rogers L. Barnes R. J. Coughlan C. McCarthy M. McDermott D. Hourihane C. O'Morain S. O'Reilly P. Hartley E. Casey L. Clancy F. Mulcahy N. Hall A. Murphy C. Breen D. Kelleher M. Abuzakouk C. O'Farrelly 《Irish journal of medical science》1992,161(6):438-442
5.
The effect of retinoic acid (RA) on testosterone metabolic pathway was investigated in hyperplastic and neoplastic human prostatic tissues, and also the effects of steroids on RA binding to its receptor. Steroids only had a minimal effect on the binding of RA by its receptor. The conversion of testosterone to DHT by 5 alpha-reductase was reduced in the presence of retinoic acid. The inhibition was probably due to competition with NADPH for enzyme binding sites. The degree of inhibition found with retinoic acid at a concentration of 10(-4)M was greater for hyperplastic (41%) than that for neoplastic tissue (24%). The inhibition of 5 alpha-reductase by retinoic acid was dose-dependent. The activity of 5 alpha-reductase is significantly less in neoplastic compared with hyperplastic tissue. 相似文献
6.
This study identifies four factors that should be considered when evaluating the reliability of new testing methods in facial nerve electroneurography (ENOG): (1) waveform peak-to-peak amplitude; (2) response variability; (3) statistical significance of day-to-day test/retest differences; and (4) waveform morphology. These factors were applied to data gathered on seven normal subjects who had three trials of facial-nerve ENOG on three separate test days in order to determine an optimal recording electrode montage. Both bipolar and monopolar recording-electrode montages were used on the nasal alae and on the nasolabial crease. Resultant peak-to-peak amplitudes of combined motor action potentials were recorded and measured using a clinical evoked-potential instrument. A biphasic waveform shape with optimal peak-to-peak point rather than the nasolabial crease. The contribution to the assessment of response reliability of each of the four factors is discussed. 相似文献
7.
目的由于卒中风险随着狭窄严重程度的增加而升高,因此认为颈内动脉(ICA)接近闭塞患者的卒中风险很高。在现有的随机试验中,还没有专门针对这种情况进行探讨,因此其处理尚存在争汶。方法:对相关文献进行系统评价。结果:对ICA接近闭塞患者的处理还存在争议:一些学者支持进行干预,而另一些学者则认为存在风险或没有益处而反对进行干预。在ICA接近闭塞的有症状患者中进行一项比较外科治疗与最佳内科治疗的多中心前瞻性随机试验似乎非常困难,因为这类研究需要大量的患者。尽管如此,基于目前的证据,似乎很难拒绝手术治疗。结论:由于目前对ICA接近闭塞患者的最佳处理方案仍存在着争议,因此需要前瞻性观察性研究以证实其在有症状和无症状人群中的患病率以及相关的卒中风险。基于目前的证据,大多数医疗中心选择手术治疗,但它相对干内科治疗的特粱尚右待证章. 相似文献
8.
9.
10.