全文获取类型
收费全文 | 40620篇 |
免费 | 3225篇 |
国内免费 | 1451篇 |
专业分类
耳鼻咽喉 | 434篇 |
儿科学 | 986篇 |
妇产科学 | 496篇 |
基础医学 | 3186篇 |
口腔科学 | 1581篇 |
临床医学 | 4946篇 |
内科学 | 6948篇 |
皮肤病学 | 1176篇 |
神经病学 | 1773篇 |
特种医学 | 2021篇 |
外科学 | 3198篇 |
综合类 | 6896篇 |
现状与发展 | 10篇 |
一般理论 | 4篇 |
预防医学 | 5406篇 |
眼科学 | 919篇 |
药学 | 2889篇 |
27篇 | |
中国医学 | 1767篇 |
肿瘤学 | 633篇 |
出版年
2024年 | 109篇 |
2023年 | 764篇 |
2022年 | 1523篇 |
2021年 | 1971篇 |
2020年 | 1851篇 |
2019年 | 1425篇 |
2018年 | 1359篇 |
2017年 | 1299篇 |
2016年 | 1511篇 |
2015年 | 1361篇 |
2014年 | 2689篇 |
2013年 | 2855篇 |
2012年 | 2484篇 |
2011年 | 2658篇 |
2010年 | 2196篇 |
2009年 | 2115篇 |
2008年 | 2002篇 |
2007年 | 2030篇 |
2006年 | 1719篇 |
2005年 | 1581篇 |
2004年 | 1248篇 |
2003年 | 1133篇 |
2002年 | 930篇 |
2001年 | 909篇 |
2000年 | 742篇 |
1999年 | 559篇 |
1998年 | 539篇 |
1997年 | 439篇 |
1996年 | 303篇 |
1995年 | 403篇 |
1994年 | 322篇 |
1993年 | 223篇 |
1992年 | 251篇 |
1991年 | 228篇 |
1990年 | 188篇 |
1989年 | 186篇 |
1988年 | 177篇 |
1987年 | 164篇 |
1986年 | 139篇 |
1985年 | 115篇 |
1984年 | 96篇 |
1983年 | 52篇 |
1982年 | 69篇 |
1981年 | 46篇 |
1980年 | 41篇 |
1979年 | 51篇 |
1978年 | 39篇 |
1977年 | 38篇 |
1976年 | 39篇 |
1974年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 748 毫秒
21.
22.
Nirmanmoh Bhatia Buddhadeb Dawn Tariq S. Siddiqui Marcus F. Stoddard 《Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital》2015,42(1):16-24
Determining aortic stenosis (AS) severity is clinically important. Calculating aortic valve (AV) area by means of the continuity equation assumes a circular left ventricular outflow tract (LVOT). The full impact of this assumption in calculating AV area is unknown. Predictors of noncircular LVOT shape in patients with AS are undefined.In 109 adult patients with AS who underwent multiplanar transesophageal echocardiography, we calculated AV area by means of the standard continuity method and by a modified method involving planimetric LVOT area.We found 54 circular, 37 horizontal-oval, 8 vertical-oval, and 10 irregular LVOTs. Area derived by direct planimetry correlated better with the modified than the standard continuity method (r=0.89 vs r=0.85; both P=0.0001). Valve areas of patients with mild, moderate, or severe AS by planimetry were more often mischaracterized with use of the standard than modified method (29 vs 18; P <0.0001). Horizontal-oval AV area derived by planimetry (1.28 ± 0.55 cm2) was underestimated by the standard method (1.05 ± 0.47 cm2; P=0.001), but not by the modified method. Congenital AV morphology and low cardiac index were the only multivariate predictors of horizontal-oval shape. Low cardiac index was the only predictor of noncircular shape.More than half our patients with AS had noncircular LVOTs. Using the modified method reduces mischaracterizations of AS severity. Congenital AV morphology and low cardiac index predict horizontal-oval or noncircular shape. These data suggest the value of direct LVOT measurement to calculate AS severity in patients who have congenital AV or a low cardiac index. 相似文献
23.
Treatment of posterior eye diseases is more challenging than the anterior segment ailments due to a series of anatomical barriers and physiological constraints confronted by drug delivery to the back of the eye. In recent years, concerted efforts in drug delivery have been made to prolong the residence time of drugs injected in the vitreous humor of the eye. Our previous studies demonstrated that poly(ortho ester) (POE) nanoparticles were biodegradable/biocompatible and were capable of long-term sustained release. The objective of the present study was to investigate the safety and localization of POE nanoparticles in New Zealand white rabbits and C57BL/6 mice after intravitreal administration for the treatment of chronic posterior ocular diseases. Two concentration levels of POE nanoparticles solution were chosen for intravitreal injection: 1.5?mg/ml and 10?mg/ml. Our results demonstrate that POE nanoparticles were distributed throughout the vitreous cavity by optical coherence tomography (OCT) examination 14 days post-intravitreal injection. Intraocular pressure was not changed from baseline. Inflammatory or adverse effects were undetectable by slit lamp biomicroscopy. Furthermore, we demonstrate that POE nanoparticles have negligible toxicity assessed at the cellular level evidenced by a lack of glia activation or apoptosis estimation after intravitreal injection. Collectively, POE nanoparticles are a novel and nontoxic as an ocular drug delivery system for the treatment of posterior ocular diseases. 相似文献
24.
25.
John Lennon Silva Cunha Amanda Almeida Leite Thamiris de Castro Abrantes Lorena Passoni Vervloet Thayn Melo de Lima Morais Gerson de Oliveira Paiva Neto Tatiana Nayara Librio Kimura Snia Maria Soares Ferreira Ricardo Luiz Cavalcanti de Albuquerque‐Júnior Aline Corrêa Abraho Mario Jos Romaach Bruno Augusto Benevenuto de Andrade Oslei Paes de Almeida Ciro Dantas Soares 《Journal of cutaneous pathology》2021,48(1):24-33
26.
Salaam Semaan 《Emerging infectious diseases》2016,22(10):1863-1864
27.
28.
Diabetes mellitus(DM) negatively affects the development and progression of chronic liver diseases(CLD) of various etiologies. Concurrent DM and CLD are also associated with worse clinical outcomes with respect to mortality, the occurrence of hepatic decompensation, and the development of hepatocellular carcinoma(HCC). Unfortunately, early diagnosis and optimal treatment of DM can be challenging, due to the lack of established clinical guidelines as well as the medical complexity of this patient population. We conducted an exploratory review of relevant literature to provide an up-to-date review for internists and hepatologists caring for this patient population. We reviewed the epidemiological and pathophysiological associations between DM and CLD, the impact of insulin resistance on the progression and manifestations of CLD, the pathogenesis of hepatogenic diabetes, as well as the practical challenges in diagnosis and monitoring of DM in this patient population. We also reviewed the latest clinical evidence on various pharmacological antihyperglycemic therapies with an emphasis on liver disease-related clinical outcomes. Finally, we proposed an algorithm for managing DM in patients with CLD and discussed the clinical and research questions that remain to be addressed. 相似文献
29.
30.