全文获取类型
收费全文 | 4942225篇 |
免费 | 408012篇 |
国内免费 | 15784篇 |
专业分类
耳鼻咽喉 | 71498篇 |
儿科学 | 157770篇 |
妇产科学 | 133717篇 |
基础医学 | 736758篇 |
口腔科学 | 143074篇 |
临床医学 | 450791篇 |
内科学 | 896620篇 |
皮肤病学 | 116746篇 |
神经病学 | 416558篇 |
特种医学 | 198968篇 |
外国民族医学 | 1270篇 |
外科学 | 750472篇 |
综合类 | 147249篇 |
现状与发展 | 23篇 |
一般理论 | 2883篇 |
预防医学 | 415500篇 |
眼科学 | 119379篇 |
药学 | 356063篇 |
19篇 | |
中国医学 | 12438篇 |
肿瘤学 | 238225篇 |
出版年
2021年 | 50502篇 |
2019年 | 59024篇 |
2018年 | 75150篇 |
2017年 | 57153篇 |
2016年 | 63845篇 |
2015年 | 76456篇 |
2014年 | 111412篇 |
2013年 | 176921篇 |
2012年 | 137685篇 |
2011年 | 144432篇 |
2010年 | 129128篇 |
2009年 | 130172篇 |
2008年 | 131450篇 |
2007年 | 140463篇 |
2006年 | 148760篇 |
2005年 | 143355篇 |
2004年 | 144314篇 |
2003年 | 133814篇 |
2002年 | 124175篇 |
2001年 | 189988篇 |
2000年 | 187643篇 |
1999年 | 168333篇 |
1998年 | 70160篇 |
1997年 | 65273篇 |
1996年 | 63082篇 |
1995年 | 64215篇 |
1994年 | 58415篇 |
1993年 | 54149篇 |
1992年 | 129232篇 |
1991年 | 124566篇 |
1990年 | 119555篇 |
1989年 | 116200篇 |
1988年 | 107986篇 |
1987年 | 106425篇 |
1986年 | 101205篇 |
1985年 | 98813篇 |
1984年 | 80514篇 |
1983年 | 70945篇 |
1982年 | 52969篇 |
1981年 | 48879篇 |
1980年 | 45935篇 |
1979年 | 73036篇 |
1978年 | 56656篇 |
1977年 | 49263篇 |
1976年 | 46083篇 |
1975年 | 46342篇 |
1974年 | 53794篇 |
1973年 | 51702篇 |
1972年 | 48514篇 |
1971年 | 44864篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
31.
32.
33.
Tellapragada Chaitanya Ydsten Karin Andersson Ternhag Anders Giske Christian G. 《European journal of clinical microbiology & infectious diseases》2022,41(7):1093-1098
European Journal of Clinical Microbiology & Infectious Diseases - We investigated the concordance between the Unyvero Hospitalized Pneumonia (HPN) application and quantitative culture for... 相似文献
34.
Moskaleva P. V. Shnayder N. A. Dmitrenko D. V. Shilkina O. S. Neznanov N. G. Nasyrova R. F. 《Neuroscience and behavioral physiology》2022,52(3):462-469
Neuroscience and Behavioral Physiology - The question of the involvement of impairments to the metabolism of melatonin and its precursors (tryptophan and serotonin) in the development of... 相似文献
35.
Qiang Liu Zhongbiao Xu Kaixuan Zhao W. Scott Hoge Xinyuan Zhang Yingjie Mei Qiqi Lu Thoralf Niendorf Yanqiu Feng 《NMR in biomedicine》2022,35(5):e4652
The purpose of this study was to investigate the feasibility of two-dimensional (2D) navigated, interleaved multishot echo-planar imaging (EPI) to enhance kidney diffusion-weighted imaging (DWI) in rats at 7.0 T. Fully sampled interleaved four-shot EPI with 2D navigators was tailored for kidney DWI (Sprague–Dawley rats, n = 7) on a 7.0-T small bore preclinical scanner. The image quality of four-shot EPI was compared with T2-weighted rapid acquisition with relaxation enhancement (RARE) (reference) and single-shot EPI (ss-EPI) without and with parallel imaging (PI). The contrast-to-noise ratio (CNR) was examined to assess the image quality for the EPI approaches. The Dice similarity coefficient and the Hausdorff distance were used for evaluation of image distortion. Mean diffusivity (MD) and fractional anisotropy (FA) were calculated for renal cortex and medulla for all DWI approaches. The corticomedullary difference of MD and FA were assessed by Wilcoxon signed-rank test. Four-shot EPI showed the highest CNR among the three EPI variants and lowest geometric distortion versus T2-weighted RARE (mean Dice: 0.77 for ss-EPI without PI, 0.88 for ss-EPI with twofold undersampling, and 0.92 for four-shot EPI). The FA map derived from four-shot EPI clearly identified a highly anisotropic region corresponding to the inner stripe of the outer medulla. Four-shot EPI successfully discerned differences in both MD and FA between renal cortex and medulla. In conclusion, 2D navigated, interleaved multishot EPI facilitates high-quality rat kidney DWI with clearly depicted intralayer and interlayer structure and substantially reduced image distortion. This approach enables the anatomic integrity of DWI-MRI in small rodents and has the potential to benefit the characterization of renal microstructure in preclinical studies. 相似文献
36.
37.
Matthias Knefel PhD Elisabeth L. Zeilinger PhD Simone Lubowitzki PhD Katharina Krammer MSc Matthias Unseld MD Rupert Bartsch MD Thorsten Fuereder MD Ulrich Jäger MD Barbara Kiesewetter MD Maria Krauth MD Markus Raderer MD Philipp B. Staber MD Peter Valent MD Alexander Gaiger MD 《Cancer》2023,129(21):3466-3475
Background
Survival in cancer patients is associated with a multitude of biological, social, and psychological factors. Although it is well established that all these factors add to overall mortality, it is not well understood how the predictive power of these parameters changes in a comprehensive model and over time.Methods
Patients who attended the authors’ outpatient clinic were invited to participate. The authors followed 5180 mixed cancer patients (51.1% female; mean age, 59.1 years [SD = 13.8]) for up to 16 years and analyzed biological (age, sex, cancer site, anemia), psychological (anxiety, depression), and social variables (marital status, education, employment status) potentially predicting overall survival in a Cox proportional hazards model.Results
The median survival time for the entire sample was 4.3 years (95% confidence interval, 4.0–4.7). The overall survival probabilities for 1 and 10 years were 76.8% and 38.0%, respectively. Following an empirical approach, the authors split the time interval into five periods: acute, subacute, short-term, medium-term, and long-term. A complex pattern of variables predicted overall survival differently in the five periods. Biological parameters were important throughout most of the time, social parameters were either time-independent predictors or tended to be more important in the longer term. Of the psychological parameters, only depression was a significant predictor and lost its predictive power in the long-term.Conclusions
The findings of this study allow the development of comprehensive patient-specific models of risk and resilience factors addressing biopsychosocial needs of cancer patients, paving the way for a personalized treatment plan that goes beyond biomedical cancer care. 相似文献38.
39.
40.