全文获取类型
收费全文 | 1399740篇 |
免费 | 115472篇 |
国内免费 | 3315篇 |
专业分类
耳鼻咽喉 | 18340篇 |
儿科学 | 46420篇 |
妇产科学 | 41034篇 |
基础医学 | 199043篇 |
口腔科学 | 37637篇 |
临床医学 | 125225篇 |
内科学 | 281745篇 |
皮肤病学 | 33328篇 |
神经病学 | 115963篇 |
特种医学 | 53774篇 |
外国民族医学 | 464篇 |
外科学 | 209951篇 |
综合类 | 32694篇 |
现状与发展 | 3篇 |
一般理论 | 487篇 |
预防医学 | 109150篇 |
眼科学 | 31385篇 |
药学 | 98147篇 |
1篇 | |
中国医学 | 3267篇 |
肿瘤学 | 80469篇 |
出版年
2019年 | 11658篇 |
2018年 | 16564篇 |
2017年 | 12668篇 |
2016年 | 14260篇 |
2015年 | 16002篇 |
2014年 | 22558篇 |
2013年 | 33387篇 |
2012年 | 45376篇 |
2011年 | 47917篇 |
2010年 | 28146篇 |
2009年 | 27046篇 |
2008年 | 44306篇 |
2007年 | 46807篇 |
2006年 | 47381篇 |
2005年 | 45849篇 |
2004年 | 43716篇 |
2003年 | 41587篇 |
2002年 | 40081篇 |
2001年 | 72875篇 |
2000年 | 74351篇 |
1999年 | 61160篇 |
1998年 | 16022篇 |
1997年 | 14378篇 |
1996年 | 14535篇 |
1995年 | 14686篇 |
1994年 | 13339篇 |
1993年 | 12514篇 |
1992年 | 45779篇 |
1991年 | 43466篇 |
1990年 | 41464篇 |
1989年 | 39529篇 |
1988年 | 36136篇 |
1987年 | 35332篇 |
1986年 | 32834篇 |
1985年 | 31257篇 |
1984年 | 23784篇 |
1983年 | 19967篇 |
1982年 | 12163篇 |
1981年 | 10728篇 |
1979年 | 20660篇 |
1978年 | 14547篇 |
1977年 | 12036篇 |
1976年 | 11315篇 |
1975年 | 11583篇 |
1974年 | 13965篇 |
1973年 | 13512篇 |
1972年 | 12622篇 |
1971年 | 11461篇 |
1970年 | 10894篇 |
1969年 | 10062篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
L.S. Becker S.K. Maschke C.L.A. Dewald T.C. Meine H.B.M. Winther M.M. Kirstein R. Kloeckner B.C. Meyer F. Wacker J.B. Hinrichs 《Clinical radiology》2021,76(2):160.e27-160.e33
43.
44.
Cécile Q.T. Nguyen Marie-Hélène Denis Miguel Chagnon Rémi Rabasa-Lhoret Geneviève Mailhot 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2021,31(1):277-285
Background and aimsDeterioration of anthropometric and lung function parameters was shown to precede the onset of cystic fibrosis-related diabetes (CFRD) in adults. In children, studies have been conducted in small cohorts with relatively short observation period. Study objectives were to document the longitudinal trends of anthropometric, pulmonary, nutritional and metabolic parameters from cystic fibrosis (CF) diagnosis to the ascertainment of abnormal glucose tolerance and identify parameters associated with the incidence of such abnormalities in a pediatric CF cohort.Methods and resultsRetrospective cohort study of 281 children with CF. Longitudinal trends of anthropometric, lung function, nutritional and metabolic data were generated from CF diagnosis to the ascertainment of abnormal glucose tolerance defined as the presence of either impaired glucose tolerance (IGT), unconfirmed CFRD or CFRD. Cox models and Kaplan–Meier curves were used to identify factors associated with developing abnormal glucose tolerance.Forty-five percent of cohort had normal glucose tolerance (NGT), 27% IGT, 10% unconfirmed CFRD and 18% CFRD. Children who developed CFRD displayed lower height z-scores from a very early age. Conversely, HbA1c levels began to rise closer to CFRD ascertainment. Height z-scores (HR: 0.45; CI 95% [0.29–0.69]) and HbA1c (HR: 2.43; CI 95% [1.86–3.18]) in years preceding ascertainment were associated with the risk of developing CFRD.ConclusionChildren who developed CFRD display distinctive trends for height z-scores from a very early age, whereas HbA1c appears as a marker of established glucose metabolism derangements. 相似文献
45.
46.
47.
48.
J. Ripollés-Melchor C. Aldecoa E. Alday-Muñoz S. del Río A. Batalla E. del-Cojo-Peces R. Uña-Orejón J.L. Muñoz-Rodés J.V. Lorente Á.V. Espinosa C. Ferrando-Ortolà J.L. Jover A. Abad-Gurumeta J.M. Ramírez-Rodríguez A. Abad-Motos 《Revista espa?ola de anestesiología y reanimación》2021,68(7):373-383
BackgroundThe optimal regimen for intravenous administration of intraoperative fluids remains unclear. Our goal was to analyze intraoperative crystalloid volume administration practices and their association with postoperative outcomes.MethodsWe extracted clinical data from two multicenter observational studies including adult patients undergoing colorectal surgery and total hip (THA) and knee arthroplasty (TKA). We analyzed the distribution of intraoperative fluid administration. Regression was performed using a general linear model to determine factors predictive of fluid administration. Patient outcomes and intraoperative crystalloid utilization were summarized for each surgical cohort. Regression models were developed to evaluate associations of high or low intraoperative crystalloid with the likelihood of increased postoperative complications, mainly acute kidney injury (AKI) and hospital length of stay (LOS).Results7,580 patients were included. The average adjusted intraoperative crystalloid infusion rate across all surgeries was to 7.9 (SD 4) mL/kg/h. The regression model strongly favored the type of surgery over other patient predictors. We found that high fluid volume was associated with 40% greater odds ratio (OR 1.40; 95% confidence interval1.01-1.95, p = 0.044) of postoperative complications in patients undergoing THA, while we found no associations for the other types of surgeries, AKI and LOSConclusionsA wide variability was observed in intraoperative crystalloid volume administration; however, this did not affect postoperative outcomes. 相似文献
49.
C. Vogrig J.-S. Louis F. Avila R. Gillet G. Hossu A. Blum-Moyse P.A. Gondim Teixeira 《Diagnostic and interventional imaging》2021,102(3):181-187
PurposeThe purpose of this study was to compare morphologic assessment and relaxometry of patellar hyaline cartilage between conventional sequences (fast spin-echo [FSE] T2-weighted fat-saturated and T2-mapping) and synthetic T2 short-TI inversion recovery (STIR) and T2 maps at 1.5 T magnetic resonance imaging (MRI).MethodThe MRI examinations of the knee obtained at 1.5 T in 49 consecutive patients were retrospectively studied. There were 21 men and 28 women with a mean age of 45 ± 17.7 (SD) years (range: 18–88 years). Conventional and synthetic acquisitions were performed, including T2-weighted fat-saturated and T2-mapping sequences. Two radiologists independently compared patellar cartilage T2-relaxation time on conventional T2-mapping and synthetic T2-mapping images. A third radiologist evaluated the patellar cartilage morphology on conventional and synthetic T2-weighted images. The presence of artifacts was also assessed. Interobserver agreement for quantitative variables was assessed using intraclass correlation coefficient (ICC).ResultsIn vitro, conventional and synthetic T2 maps yielded similar mean T2 values 58.5 ± 2.3 (SD) ms and 58.8 ± 2.6 (SD) ms, respectively (P = 0.414) and 6% lower than the expected experimental values (P = 0.038). Synthetic images allowed for a 15% reduction in examination time compared to conventional images. On conventional sequences, patellar chondropathy was identified in 35 patients (35/49; 71%) with a mean chondropathy grade of 4.8 ± 4.8 (SD). On synthetic images, 28 patients (28/49; 57%) were diagnosed with patellar chondropathy, with a significant 14% difference (P = 0.009) and lower chondropathy scores (3.7 ± 4.9 [SD]) compared to conventional images. Motion artifacts were more frequently observed on synthetic images (18%) than on conventional ones (6%). The interobserver agreement was excellent for both conventional and synthetic T2 maps (ICC > 0.83). Mean cartilage T2 values were significantly greater on synthetic images (36.2 ± 3.8 [SD] ms; range: 29-46 ms) relative to conventional T2 maps (31.8 ± 4.1 [SD] ms; range: 26-49 ms) (P < 0.0001).ConclusionDespite a decrease in examination duration, synthetic images convey lower diagnostic performance for chondropathy, greater prevalence of motion artifacts, and an overestimation of T2 values compared to conventional MRI sequences. 相似文献
50.