全文获取类型
收费全文 | 50894篇 |
免费 | 4978篇 |
国内免费 | 889篇 |
专业分类
耳鼻咽喉 | 117篇 |
儿科学 | 957篇 |
妇产科学 | 1327篇 |
基础医学 | 3558篇 |
口腔科学 | 211篇 |
临床医学 | 10243篇 |
内科学 | 6756篇 |
皮肤病学 | 361篇 |
神经病学 | 976篇 |
特种医学 | 3615篇 |
外国民族医学 | 6篇 |
外科学 | 5373篇 |
综合类 | 7994篇 |
现状与发展 | 3篇 |
预防医学 | 2574篇 |
眼科学 | 455篇 |
药学 | 2976篇 |
56篇 | |
中国医学 | 939篇 |
肿瘤学 | 8264篇 |
出版年
2024年 | 96篇 |
2023年 | 803篇 |
2022年 | 1517篇 |
2021年 | 2117篇 |
2020年 | 2273篇 |
2019年 | 1998篇 |
2018年 | 1948篇 |
2017年 | 2103篇 |
2016年 | 2074篇 |
2015年 | 2104篇 |
2014年 | 3910篇 |
2013年 | 3383篇 |
2012年 | 2986篇 |
2011年 | 3425篇 |
2010年 | 2524篇 |
2009年 | 2537篇 |
2008年 | 2632篇 |
2007年 | 2568篇 |
2006年 | 2174篇 |
2005年 | 1825篇 |
2004年 | 1541篇 |
2003年 | 1420篇 |
2002年 | 1113篇 |
2001年 | 1019篇 |
2000年 | 886篇 |
1999年 | 786篇 |
1998年 | 647篇 |
1997年 | 594篇 |
1996年 | 500篇 |
1995年 | 483篇 |
1994年 | 410篇 |
1993年 | 305篇 |
1992年 | 277篇 |
1991年 | 234篇 |
1990年 | 197篇 |
1989年 | 159篇 |
1988年 | 152篇 |
1987年 | 118篇 |
1986年 | 108篇 |
1985年 | 156篇 |
1984年 | 134篇 |
1983年 | 63篇 |
1982年 | 94篇 |
1981年 | 72篇 |
1980年 | 80篇 |
1979年 | 46篇 |
1978年 | 44篇 |
1977年 | 28篇 |
1974年 | 24篇 |
1973年 | 24篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
31.
32.
33.
34.
Anastasiia Panfilova Sarah E. Shelton Cristina Caresio Ruud J.G. van Sloun Filippo Molinari Hessel Wijkstra Paul A. Dayton Massimo Mischi 《Ultrasound in medicine & biology》2019,45(2):539-548
Dynamic contrast-enhanced ultrasound (DCE-US) has been proposed as a powerful tool for cancer diagnosis by estimation of perfusion and dispersion parameters reflecting angiogenic vascular changes. This work was aimed at identifying which vascular features are reflected by the estimated perfusion and dispersion parameters through comparison with acoustic angiography (AA). AA is a high-resolution technique that allows quantification of vascular morphology. Three-dimensional AA and 2-D DCE-US bolus acquisitions were used to monitor the growth of fibrosarcoma tumors in nine rats. AA-derived vascular properties were analyzed along with DCE-US perfusion and dispersion to investigate the differences between tumor and control and their evolution in time. AA-derived microvascular density and DCE-US perfusion exhibited good agreement, confirmed by their spatial distributions. No vascular feature was correlated with dispersion. Yet, dispersion provided better cancer classification than perfusion. We therefore hypothesize that dispersion characterizes vessels that are smaller than those visible with AA. 相似文献
35.
36.
37.
38.
39.
Rian M. Hasson Kayla A. Fay Joseph D. Phillips Timothy M. Millington David J. Finley 《American journal of surgery》2021,221(4):725-730
BackgroundRural populations face many health disadvantages compared to urban areas. There is a critical need to better understand the current lung cancer screening landscape in these communities to identify targeted areas to improve the impact of this proven tool.MethodsData from the County Health Rankings of New Hampshire and Vermont was reviewed for population density, distribution of adult smokers, and level of education compared to the distribution of Lung Cancer Screening Facilities throughout these two states.ResultsScreening programs in southern counties of Vermont with lower levels of education have decreased access. In New Hampshire, there are no programs within 30 miles of the areas with the largest distribution of smokers, and decreased access in some areas with the lowest levels of education.ConclusionsImproving equitable access to high-quality screening services in rural regions and the creation of targeted interventions to address decreased access in areas of high tobacco use and low education is vital to decreasing the incidence of latestage presentations of lung cancer within these populations. 相似文献
40.