全文获取类型
收费全文 | 3205篇 |
免费 | 152篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 135篇 |
妇产科学 | 78篇 |
基础医学 | 418篇 |
口腔科学 | 47篇 |
临床医学 | 263篇 |
内科学 | 800篇 |
皮肤病学 | 74篇 |
神经病学 | 306篇 |
特种医学 | 59篇 |
外科学 | 381篇 |
综合类 | 6篇 |
一般理论 | 1篇 |
预防医学 | 128篇 |
眼科学 | 66篇 |
药学 | 177篇 |
中国医学 | 9篇 |
肿瘤学 | 412篇 |
出版年
2023年 | 18篇 |
2022年 | 34篇 |
2021年 | 54篇 |
2020年 | 47篇 |
2019年 | 58篇 |
2018年 | 76篇 |
2017年 | 57篇 |
2016年 | 51篇 |
2015年 | 83篇 |
2014年 | 117篇 |
2013年 | 111篇 |
2012年 | 202篇 |
2011年 | 203篇 |
2010年 | 134篇 |
2009年 | 128篇 |
2008年 | 215篇 |
2007年 | 218篇 |
2006年 | 207篇 |
2005年 | 201篇 |
2004年 | 199篇 |
2003年 | 190篇 |
2002年 | 179篇 |
2001年 | 63篇 |
2000年 | 33篇 |
1999年 | 40篇 |
1998年 | 32篇 |
1997年 | 34篇 |
1996年 | 37篇 |
1995年 | 30篇 |
1994年 | 22篇 |
1993年 | 17篇 |
1992年 | 25篇 |
1991年 | 26篇 |
1990年 | 23篇 |
1989年 | 28篇 |
1988年 | 26篇 |
1987年 | 21篇 |
1986年 | 13篇 |
1985年 | 10篇 |
1984年 | 16篇 |
1983年 | 6篇 |
1982年 | 13篇 |
1981年 | 3篇 |
1980年 | 14篇 |
1979年 | 13篇 |
1978年 | 10篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1975年 | 6篇 |
1970年 | 2篇 |
排序方式: 共有3368条查询结果,搜索用时 15 毫秒
51.
52.
Objectives: Visual hallucinations (VH) are common in Lewy body disease (LBD), and have been associated with cognitive and structural brain alterations. Evidence so far concerns mainly Parkinson’s disease (PD), but little is known about symptom-specific pathophysiological mechanisms across the LBD spectrum, especially related to the presence of dementia. The aim of the present pilot study was to investigate the neuroanatomical, and neuropsychological characteristics related to VH in two forms of LBD, namely dementia with Lewy bodies (DLB) and PD without dementia.Methods: Whole brain voxel-based morphometry (VBM) analyses on 3D MRI acquired structural brain scans, and neuropsychological testing were performed on 28 clinically diagnosed DLB (11 with VH, 17 NVH), and 24 PD (9 with VH, and 15 NVH) patients. In order to assess differences in gray matter (GM) regional volumes, and cognitive performance, hallucinating patients for each group were compared with corresponding non-hallucinating ones.Results: DLB patients with VH presented significantly worse visual attention deficits compared to those without, which persisted even when controlling for visual perception. Whole brain VBM analysis revealed decreased GM volume in DLB with VH in the right superior and medial frontal gyri, putamen, caudate nucleus and insula. Subcortical regional volumes were also significantly associated with visual attention performance. Hallucinating PD patients, instead, presented more severe executive dysfunction, but VBM showed no volumetric differences between the two PD subgroups. Post hoc region of interest analyses revealed striatal GM loss in PD with VH.Conclusion: Frontal and striatal GM atrophy may contribute to the emergence of VH in DLB, which may be fostered by the more severe attention deficits. Striatal GM loss and executive dysfunction, instead, appeared to underlie VH in PD without dementia. 相似文献
53.
Eduardo Suárez-Castaneda Lorenzo Pezzoli Miguel Elas Rafael Baltrons Elner Osmin Crespin-Elías Oscar A. Rivera Pleitez María Isabel Quintanilla de Campos M. Carolina Danovaro-Holliday 《Vaccine》2014
While assessing immunization programmes, not only vaccination coverage is important, but also timely receipt of vaccines. We estimated both vaccination coverage and timeliness, as well as reasons for non-vaccination, and identified predictors of delayed or missed vaccination, for vaccines of the first two years of age, in El Salvador. 相似文献
54.
55.
Sara Ariotti Maarten van Leeuwen Salvatore Brugaletta Sergio Leonardi K. Martijn Akkerhuis Stefano F. Rimoldi Gladys N. Janssens Luis Ortega-Paz Umberto Gianni Jan C. van den Berge Alexios Karagiannis Stephan Windecker Marco Valgimigli 《Journal of the American College of Cardiology》2018,71(11):1289-1291
56.
57.
In-Cheol Kim Geu-Ru Hong Gianni Pedrizzetti Chi Young Shim Seok-Min Kang Namsik Chung 《Ultrasound in medicine & biology》2018,44(9):1951-1959
The goal of the study described here was to evaluate whether left ventricular vortex flow parameters, as assessed by contrast echocardiography, enhance prediction of major adverse cardiac events (MACE) in patients with chronic heart failure and systolic dysfunction. A total of 75 patients with contrast echocardiography and systolic dysfunction (ejection fraction ≤45%) were prospectively enrolled and underwent vortex flow analysis with particle image velocimetry using contrast echocardiography. Vortex flow parameters, including kinetic energy fluctuation (KEF), were evaluated. Patients were followed up for a primary endpoint of MACE that comprised hospital admission for cardiovascular causes and cardiac deaths. Across a median 277-d follow-up, 29 patients (38.7%) experienced MACE. Among these, the incidence of diabetes and the E/e' ratio were significantly higher in patients with MACE than in those without, whereas the hemoglobin level and ejection fraction were significantly lower. KEF was significantly lower in patients with MACE. In the multivariate analysis, higher KEF was associated with a lower risk of MACE (hazard ratio?=?0.18, 95% confidence interval: 0.04–0.97, p?=?0.046). The addition of KEF to a model with conventional parameters (e.g., age, diabetes, ejection fraction and the E/e' ratio) significantly improved the model's discrimination. Elevations in the quantitative left ventricular vortex flow parameter, KEF, as determined by contrast echocardiography, are associated with a lower risk of MACE and improved functional status among patients with chronic heart failure. 相似文献
58.
Asif Padiyath M.D. Paul Gribben B.S. Joseph R. Abraham B.S. Ling Li M.D. Ph.D. Sheela Rangamani M.D. Andreas Schuster M.D. David A. Danford M.D. Gianni Pedrizzetti Ph.D. Shelby Kutty M.D. 《Echocardiography (Mount Kisco, N.Y.)》2013,30(2):203-210
We investigated intermodality agreements of strains from two‐dimensional echocardiography (2DE) and cardiac magnetic resonance (CMR) feature tracking (FT) in the assessment of right (RV) and left ventricular (LV) mechanics in tetralogy of Fallot (TOF). Patients were prospectively studied with 2DE and CMR performed contiguously. LV and RV strains were computed separately using 2DE and CMR‐FT. Segmental and global longitudinal strains (GLS) for the LV and RV were measured from four‐chamber views; LV radial (global radial strain [GRS]) and circumferential strains (GCS) measured from short‐axis views. Intermodality and interobserver agreements were examined. In 40 patients (20 TOF, mean age 23 years and 20 adult controls), LV, GCS showed narrowest intermodality limits of agreement (mean percentage error 9.5%), followed by GLS (16.4%). RV GLS had mean intermodality difference of 25.7%. GLS and GCS had acceptable interobserver agreement for the LV and RV with both 2DE and CMR‐FT, whereas GRS had high interobserver and intermodality variability. In conclusion, myocardial strains for the RV and LV derived using currently available 2DE and CMR‐FT software are subject to considerable intermodality variability. For both modalities, LV GCS, LV GLS, and RV GLS are reproducible enough to warrant further investigation of incremental clinical merit. 相似文献
59.
V. Isella C. Mapelli N. Morielli D. De Gaspari C. Siri G. Pezzoli A. Antonini M. Poletti U. Bonuccelli L. Picchi A. Napolitano M. Vista A. Greco I. M. Appollonio 《Neurological sciences》2013,34(10):1751-1758
The MiniMental Parkinson (MMP) has been derived from the MiniMental State Examination (MMSE) for the screening of cognitive impairment in Parkinson’s disease by adding subtests that were focused on executive and visuo-spatial impairment more than on memory or language deficits. In this multicenter study, the psychometric and validity properties of the MMP have been evaluated in 69 cognitively intact and 52 cognitively impaired patients with Parkinson’s disease, classified according to their performance at the Dementia Rating Scale. The MMP showed better metrics and convergent validity, and higher screening ability. However, its performance was not fully satisfying in terms of data distribution, coefficient of variation and specificity, and Receiver Operating Characteristic curves did not show clear cut superiority of either scale at their best sensitivity–specificity trade off. The MMP seems to be slightly preferable to the MMSE only at a cut off that favours sensitivity with respect to specificity, for screening purposes. The test is simple and quick, but has limitations in terms of validity. 相似文献
60.
Noemie Luong-Gardiol Imran Siddiqui Irene Pizzitola Beena Jeevan-Raj Mélanie Charmoy Yun Huang Anja Irmisch Sara Curtet Georgi S. Angelov Maxime Danilo Mélanie Juilland Beat Bornhauser Margot Thome Oliver Hantschel Yves Chalandon Gianni Cazzaniga Jean-Pierre Bourquin Joerg Huelsken Werner Held 《Cancer cell》2019,35(4):649-663.e10