全文获取类型
收费全文 | 180756篇 |
免费 | 34500篇 |
国内免费 | 2471篇 |
专业分类
耳鼻咽喉 | 5384篇 |
儿科学 | 6337篇 |
妇产科学 | 3008篇 |
基础医学 | 7433篇 |
口腔科学 | 2486篇 |
临床医学 | 29781篇 |
内科学 | 53324篇 |
皮肤病学 | 7978篇 |
神经病学 | 17996篇 |
特种医学 | 7434篇 |
外国民族医学 | 6篇 |
外科学 | 45064篇 |
综合类 | 658篇 |
现状与发展 | 72篇 |
一般理论 | 51篇 |
预防医学 | 9281篇 |
眼科学 | 4444篇 |
药学 | 3440篇 |
中国医学 | 61篇 |
肿瘤学 | 13489篇 |
出版年
2024年 | 695篇 |
2023年 | 4841篇 |
2022年 | 1359篇 |
2021年 | 3478篇 |
2020年 | 6243篇 |
2019年 | 2567篇 |
2018年 | 7882篇 |
2017年 | 7707篇 |
2016年 | 8808篇 |
2015年 | 8848篇 |
2014年 | 16113篇 |
2013年 | 16698篇 |
2012年 | 7270篇 |
2011年 | 7468篇 |
2010年 | 11376篇 |
2009年 | 15182篇 |
2008年 | 7714篇 |
2007年 | 6229篇 |
2006年 | 8579篇 |
2005年 | 5938篇 |
2004年 | 5133篇 |
2003年 | 4089篇 |
2002年 | 4102篇 |
2001年 | 4117篇 |
2000年 | 3270篇 |
1999年 | 3551篇 |
1998年 | 4068篇 |
1997年 | 3835篇 |
1996年 | 3660篇 |
1995年 | 3516篇 |
1994年 | 2242篇 |
1993年 | 1863篇 |
1992年 | 1645篇 |
1991年 | 1666篇 |
1990年 | 1277篇 |
1989年 | 1363篇 |
1988年 | 1215篇 |
1987年 | 1042篇 |
1986年 | 1101篇 |
1985年 | 920篇 |
1984年 | 866篇 |
1983年 | 813篇 |
1982年 | 881篇 |
1981年 | 718篇 |
1980年 | 686篇 |
1979年 | 495篇 |
1978年 | 542篇 |
1977年 | 619篇 |
1975年 | 430篇 |
1972年 | 397篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
A high resolution depth attenuation product (Kdhires) was developed using MODIS 500 m and 250 m spectral bands. The Kdhires was compared with Wang’s operational Kd for the Chesapeake Bay. Minimal differences were observed between the two methods, with greatest deviation occurring in areas of high turbidity in the tributaries. After tuning the new Kdhires, the mean absolute error and bias between the two algorithms was 0.22 m?1 and 0.026 m?1, indicating good agreement. Higher spatial resolution provides for improved retrievals along the coast and into the narrow sections of the tributaries, coinciding with areas of concern to estuarine health and coastal management applications. 相似文献
93.
94.
Gary E. Stapleton Benjamin W. Eidem Ricardo H. Pignatelli Karina M. Carlson Charles E. Mullins Ronald G. Grifka 《Congenital heart disease》2006,1(3):116-119
Background. A persistent patent ductus arteriosus (PDA) may delay closure of a coexisting atrial septal defect (ASD) due to volume loading and enlargement of the left atrium. The purpose of this study was to investigate the natural history of ASD size in patients with a PDA following transcatheter PDA occlusion. Methods. All patients with an ASD and a PDA who underwent transcatheter PDA occlusion at Texas Children’s Hospital were identified. Patients with ASD diameter <3 mm, or additional cardiac defects were excluded. Eight patients (7 females) with small‐ to moderate‐sized ASDs and a PDA were identified. Patient demographics, echocardiographic data, and cardiac catheterization data were recorded. Data were analyzed by 1‐tailed t‐test. Results. Following PDA occlusion, ASD diameter decreased in 6 of 8 patients by a mean of 3.8 mm (±2.3 mm), including 2 that closed. The median duration of follow‐up was 689 days. One ASD remained unchanged and 1 increased in size. The mean maximum ASD diameter decreased from 6.4 mm (±2.2 mm) to 3.9 mm (±3.4 mm) (P = .03). Two patients underwent subsequent transcatheter ASD occlusion. Conclusion. Following transcatheter PDA occlusion, small‐ to moderate‐sized ASDs have significant probability to decrease in size, and possibly close. In infants and children, we recommend transcatheter PDA occlusion, and serial follow‐up of the size of the ASD. This will allow many small‐ to moderate‐sized ASDs to either close, or become smaller, obviating the need for future intervention. 相似文献
95.
Juliette A. Loncaster MD FRCR Ernest Allan 《Photodiagnosis and Photodynamic Therapy》2006,3(2):134-137
Gorlin syndrome (naevoid basal cell carcinoma syndrome) is a genetically linked disorder characterized by the development of multiple basal cell carcinomas (BCCs) throughout life. Cumulative surgery, cryotherapy and other conventional interventions can result in significant disfigurement by middle age. Radiotherapy is contra-indicated because the mutated gene underlying the syndrome, ‘PTCH’, increases sensitivity to ionising radiation, so there is significant likelihood of inducing further tumours in and around the irradiated area. Photodynamic therapy offers a non-invasive treatment option for patients with this condition, with the added advantage of causing minimal scarring. 相似文献
96.
97.
98.
99.
100.