全文获取类型
收费全文 | 252485篇 |
免费 | 17811篇 |
国内免费 | 1130篇 |
专业分类
耳鼻咽喉 | 2815篇 |
儿科学 | 6503篇 |
妇产科学 | 4602篇 |
基础医学 | 32977篇 |
口腔科学 | 4559篇 |
临床医学 | 25362篇 |
内科学 | 53673篇 |
皮肤病学 | 3384篇 |
神经病学 | 24323篇 |
特种医学 | 8407篇 |
外国民族医学 | 11篇 |
外科学 | 38564篇 |
综合类 | 3460篇 |
一般理论 | 318篇 |
预防医学 | 21437篇 |
眼科学 | 6558篇 |
药学 | 16997篇 |
6篇 | |
中国医学 | 361篇 |
肿瘤学 | 17109篇 |
出版年
2023年 | 1340篇 |
2022年 | 2409篇 |
2021年 | 5445篇 |
2020年 | 3265篇 |
2019年 | 5308篇 |
2018年 | 5955篇 |
2017年 | 4478篇 |
2016年 | 4965篇 |
2015年 | 5836篇 |
2014年 | 8620篇 |
2013年 | 11803篇 |
2012年 | 18029篇 |
2011年 | 18919篇 |
2010年 | 10588篇 |
2009年 | 9441篇 |
2008年 | 16609篇 |
2007年 | 17461篇 |
2006年 | 17310篇 |
2005年 | 17283篇 |
2004年 | 16199篇 |
2003年 | 15050篇 |
2002年 | 14069篇 |
2001年 | 2117篇 |
2000年 | 1608篇 |
1999年 | 2329篇 |
1998年 | 3072篇 |
1997年 | 2562篇 |
1996年 | 2186篇 |
1995年 | 2098篇 |
1994年 | 1745篇 |
1993年 | 1577篇 |
1992年 | 1267篇 |
1991年 | 1159篇 |
1990年 | 1013篇 |
1989年 | 981篇 |
1988年 | 981篇 |
1987年 | 951篇 |
1986年 | 958篇 |
1985年 | 973篇 |
1984年 | 1222篇 |
1983年 | 1126篇 |
1982年 | 1365篇 |
1981年 | 1314篇 |
1980年 | 1146篇 |
1979年 | 708篇 |
1978年 | 755篇 |
1977年 | 638篇 |
1976年 | 586篇 |
1975年 | 475篇 |
1974年 | 474篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
13.
14.
15.
Krishna Pillai Javid Akhter Terence C. Chua Mena Shehata Nayef Alzahrani Issan Al-Alem David L. Morris 《Medicine》2015,94(9)
Thermal ablation of liver tumors near large blood vessels is affected by the cooling effect of blood flow, leading to incomplete ablation. Hence, we conducted a comparative investigation of heat sink effect in monopolar (MP) and bipolar (BP) radiofrequency ablation (RFA), and microwave (MW) ablation devices.With a perfused calf liver, the ablative performances (volume, mass, density, dimensions), with and without heat sink, were measured. Heat sink was present when the ablative tip of the probes were 8.0 mm close to a major hepatic vein and absent when >30 mm away. Temperatures (T1 and T2) on either side of the hepatic vein near the tip of the probes, heating probe temperature (T3), outlet perfusate temperature (T4), and ablation time were monitored.With or without heat sink, BP radiofrequency ablated a larger volume and mass, compared with MP RFA or MW ablation, with latter device producing the highest density of tissue ablated. MW ablation produced an ellipsoidal shape while radiofrequency devices produced spheres.Percentage heat sink effect in Bipolar radiofrequency : Mono-polar radiofrequency : Microwave was (Volume) 33:41:22; (mass) 23:56:34; (density) 9.0:26:18; and (relative elipscity) 5.8:12.9:1.3, indicating that BP and MW devices were less affected.Percentage heat sink effect on time (minutes) to reach maximum temperature (W) = 13.28:9.2:29.8; time at maximum temperature (X) is 87:66:16.66; temperature difference (Y) between the thermal probes (T3) and the temperature (T1 + T2)/2 on either side of the hepatic vessel was 100:87:20; and temperature difference between the (T1 + T2)/2 and temperature of outlet circulating solution (T4), Z was 20.33:30.23:37.5.MW and BP radiofrequencies were less affected by heat sink while MP RFA was the most affected. With a single ablation, BP radiofrequency ablated a larger volume and mass regardless of heat sink. 相似文献
16.
17.
18.
The present narrative review examines the scientific evidence of the biological mechanisms that may link periodontitis and diabetes, as a source of comorbidity. Publications regarding periodontitis and diabetes, in human, animals, and in vitro were screened for their relevance. Periodontal microbiome studies indicate a possible association between altered glucose metabolism in prediabetes and diabetes and changes in the periodontal microbiome. Coinciding with this, hyperglycemia enhances expression of pathogen receptors, which enhance host response to the dysbiotic microbiome. Hyperglycemia also promotes pro-inflammatory response independently or via the advanced glycation end product/receptor for advanced glycation end product pathway. These processes excite cellular tissue destruction functions, which further enhance pro-inflammatory cytokines expression and alteration in the RANKL/osteoprotegerin ratio, promoting formation and activation of osteoclasts. The evidence supports the role of several pathogenic mechanisms in the path of true causal comorbidity between poorly controlled diabetes and periodontitis. However, further research is needed to better understand these mechanisms and to explore other mechanisms. 相似文献
19.
20.
Jamaal L. Benjamin MD PhD Rebecca Dennis DO Stacy White Jr MD David Munson MD Sudha A. Anupindi MD Maciej Piskunowicz MD Kassa Darge MD PhD Ami Gokli MD Misun Hwang MD 《Journal of ultrasound in medicine》2020,39(5):1031-1036
Bowel diseases of prematurity, including necrotizing enterocolitis, are dreaded ailments of neonates. Early diagnosis is difficult, with clinical and radiographic findings often inconclusive. We present a novel use of contrast-enhanced ultrasound in detection of pediatric bowel disease. Early identification of compromised blood flow or an at-risk bowel can be quantitatively detected and monitored. This ability has implications for guidance of emerging therapies, allowing targeting of inflammation. These findings represent an advancement in detection of bowel disease in neonates. 相似文献