全文获取类型
收费全文 | 45364篇 |
免费 | 3195篇 |
国内免费 | 172篇 |
专业分类
耳鼻咽喉 | 422篇 |
儿科学 | 1126篇 |
妇产科学 | 730篇 |
基础医学 | 6519篇 |
口腔科学 | 766篇 |
临床医学 | 4767篇 |
内科学 | 9832篇 |
皮肤病学 | 929篇 |
神经病学 | 4707篇 |
特种医学 | 1743篇 |
外国民族医学 | 11篇 |
外科学 | 6169篇 |
综合类 | 467篇 |
一般理论 | 44篇 |
预防医学 | 3589篇 |
眼科学 | 823篇 |
药学 | 3248篇 |
中国医学 | 126篇 |
肿瘤学 | 2713篇 |
出版年
2023年 | 353篇 |
2022年 | 593篇 |
2021年 | 1168篇 |
2020年 | 798篇 |
2019年 | 1069篇 |
2018年 | 1264篇 |
2017年 | 996篇 |
2016年 | 1138篇 |
2015年 | 1232篇 |
2014年 | 1672篇 |
2013年 | 2089篇 |
2012年 | 3279篇 |
2011年 | 3397篇 |
2010年 | 1942篇 |
2009年 | 1647篇 |
2008年 | 2699篇 |
2007年 | 2863篇 |
2006年 | 2687篇 |
2005年 | 2444篇 |
2004年 | 2284篇 |
2003年 | 1930篇 |
2002年 | 1801篇 |
2001年 | 648篇 |
2000年 | 650篇 |
1999年 | 603篇 |
1998年 | 416篇 |
1997年 | 317篇 |
1996年 | 296篇 |
1995年 | 270篇 |
1994年 | 214篇 |
1993年 | 183篇 |
1992年 | 341篇 |
1991年 | 313篇 |
1990年 | 327篇 |
1989年 | 261篇 |
1988年 | 260篇 |
1987年 | 299篇 |
1986年 | 310篇 |
1985年 | 283篇 |
1984年 | 234篇 |
1983年 | 184篇 |
1982年 | 146篇 |
1981年 | 139篇 |
1980年 | 135篇 |
1979年 | 242篇 |
1978年 | 175篇 |
1977年 | 146篇 |
1976年 | 132篇 |
1974年 | 135篇 |
1973年 | 151篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Marcel Toussaint Raymond J. Gilles Noura Azzabou Benjamin Marty Alexandre Vignaud Andreas Greiser Pierre G. Carlier 《Medicine》2015,94(43)
Delayed contrast enhancement after injection of a gadolinium-chelate (Gd-chelate) is a reference imaging method to detect myocardial tissue changes. Its localization within the thickness of the myocardial wall allows differentiating various pathological processes such as myocardial infarction (MI), inflammatory myocarditis, and cardiomyopathies. The aim of the study was first to characterize benign myocarditis using quantitative delayed-enhancement imaging and then to investigate whether the measure of the extracellular volume fraction (ECV) can be used to discriminate between MI and myocarditis.In 6 patients with acute benign myocarditis (32.2 ± 13.8 year-old, subepicardial late gadolinium enhancement [LGE]) and 18 patients with MI (52.3 ± 10.9 year-old, subendocardial/transmural LGE), myocardial T1 was determined using the Modified Look-Locker Imaging (MOLLI) sequence at 3 Tesla before and after Gd-chelate injection. T1 values were compared in LGE and normal regions of the myocardium. The myocardial T1 values were normalized to the T1 of blood, and the ECV was calculated from T1 values of myocardium and blood pre- and post-Gd injection.In both myocarditis and MI, the T1 was lower in LGE regions than in normal regions of the left ventricle. T1 of LGE areas was significantly higher in myocarditis than in MI (446.8 ± 45.8 vs 360.5 ± 66.9 ms, P = 0.003) and ECV was lower in myocarditis than in MI (34.5 ± 3.3 vs 53.8 ± 13.0 %, P = 0.004).Both inflammatory process and chronic fibrosis induce LGE (subepicardial in myocarditis and subendocardial in MI). The present study demonstrates that the determination of T1 and ECV is able to differentiate the 2 histological patterns.Further investigation will indicate whether the severity of ECV changes might help refine the predictive risk of LGE in myocarditis. 相似文献
3.
4.
Objectives
Iatrogenic injury of the Profunda Femoris Artery (PFA) at time of hip fixation surgery can increase morbidity and mortality and prolong the hospital stay. This is an injury that tends to pass unnoticed as a cause of postoperative deterioration despite being frequently reported in the literature. Our study aims to describe the anatomy of the PFA in relation to the medial femoral cortex with specific emphasis on its orientation relative to the position of a sliding hip screw side plate construct. By doing so we are able to present clear guidance to orthopaedic surgeons on how to avoid iatrogenic PFA injury at the time of hip fracture fixation.Methods
Using Computed Tomography Angiographic (CTA) studies, the course of the PFA in relation to the medial femoral cortex was traced in 44 patients (28 males and 16 females) with mean age of 65.6 years. Coronal and axial CT sections were cross-linked to specify the position of the PFA at 1?cm intervals.Results
The course of the artery could be divided into three parts relative to a fixed reference point. Proximal and distal parts of the artery were in a safer position in comparison to the middle part of the artery that was found very close to the femoral cortex and along the coronal axis of the femur (mean angle 2.9° from the femoral coronal axis and 13.8?mm from the medial femoral cortex). Using the commercially available side plate constructs, this part of the artery corresponded to the distal part of the plate (third and fourth holes).Conclusion
Special attention needs to be practiced by the operating surgeon while drilling into the third and fourth holes of the side plate. 相似文献5.
Adilson Cunha Ferreira Edward Araujo Júnior Wellington P. Martins João Francisco Jordão Antônio Hélio Oliani Simon E. Meagher 《The journal of maternal-fetal & neonatal medicine》2015,28(14):1706-1710
Objective: To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.Methods: In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.Results: The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI?=?66.4–86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI?=?70.0–80.8%) the scores of transmitted image were considered the same as the original.Conclusion: We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality. 相似文献
6.
7.
Lara Feulner Hamed S. Najafabadi Simon Tanguay Janusz Rak Yasser Riazalhosseini 《Urologic oncology》2019,37(2):166-175
Background
Clear cell renal cell carcinoma (ccRCC) is known to occur across the adult lifetime traversing the spectrum of age-related organismal changes. Little is known as to how the aging process may affect the course of renal cell carcinoma (RCC) and the repertoire of genes involved.Methods
Using The Cancer Genome Atlas (n?=?436) and Cancer Genomics of the Kidney (n?=?89) datasets, we applied regression analysis to examine associations between patient age and gene expression profiles in ccRCC tumors and normal kidney tissues. Pathway enrichment analysis was performed to identify cellular process that is affected by aging in ccRCC. Moreover, connectivity mapping analysis was used to predict age-dependent response to drug treatments.Results
Our analysis revealed different age-dependent gene expression spectra in ccRCC and normal kidney tissues. These findings were significant and independently reproducible in both datasets examined. Age up-regulated genes, showing higher expression in older patients, were significantly enriched (false discovery rate <0.05) in normal tissues for pathways associated with immune response and extracellular matrix organization, whereas age up-regulated genes in tumors were enriched for metabolism and oxidation pathways. Strikingly, age down-regulated genes in normal cells were also enriched for metabolism and oxidation, while those in tumors were enriched for extracellular matrix organization. Further in silico analysis of potential drug targets predicted preferential efficacy of Phosphoinositide 3-kinase inhibitor or immunotherapy in association with age.Conclusion
We report on previously unrecognized associations between age and molecular underpinnings of RCC, including age-associated expression of genes implicated in RCC development or treatment. 相似文献8.
9.
Jeroen M. van de Pol Jurjen G. Geljon Svetlana V. Belitser Geert W.J. Frederix Anke M. Hövels Marcel L. Bouvy 《Research in social & administrative pharmacy》2019,15(1):70-76
Introduction
The nature of community pharmacy is changing, shifting from the preparation and distribution of medicines to the provision of cognitive pharmaceutical services (CPS); however, often the provision of traditional services leaves little time for innovative services. This study investigated the time community pharmacists spend on the tasks and activities of daily practice and to what extent they are able to implement CPS-related services in daily practice.Methods
Self-reporting work sampling was used to register the activities of community pharmacists. A smartphone application, designed specifically for this purpose, alerted participants to register their current activity five times per working day for 6 weeks. Participants also completed an online survey about baseline characteristics.Results
Ninety-one Dutch community pharmacists provided work-sampling data (7848 registered activities). Overall, 51.5% of their time was spent on professional activities, 35.4% on semi-professional activities, and 13.1% on non-professional activities. The proportion of time devoted to CPS decreased during the workweek, whereas the time spent on traditional task increased.Discussion and conclusion
This study shows it is feasible to collect work-sampling data using smartphone technology. Community pharmacists spent almost half of their time on semi-professional and non-professional activities, activities that could be delegated to other staff members. In practice, the transition to CPS is hampered by competing traditional tasks, which prevents community pharmacists from profiling themselves as pharmaceutical experts in daily practice. 相似文献10.