全文获取类型
收费全文 | 57998篇 |
免费 | 5016篇 |
国内免费 | 1986篇 |
专业分类
耳鼻咽喉 | 652篇 |
儿科学 | 1012篇 |
妇产科学 | 626篇 |
基础医学 | 11420篇 |
口腔科学 | 979篇 |
临床医学 | 3634篇 |
内科学 | 9006篇 |
皮肤病学 | 1258篇 |
神经病学 | 4185篇 |
特种医学 | 953篇 |
外国民族医学 | 16篇 |
外科学 | 4502篇 |
综合类 | 6805篇 |
现状与发展 | 9篇 |
预防医学 | 2308篇 |
眼科学 | 668篇 |
药学 | 9622篇 |
2篇 | |
中国医学 | 2398篇 |
肿瘤学 | 4945篇 |
出版年
2024年 | 159篇 |
2023年 | 1160篇 |
2022年 | 2383篇 |
2021年 | 2455篇 |
2020年 | 1959篇 |
2019年 | 2324篇 |
2018年 | 2414篇 |
2017年 | 2320篇 |
2016年 | 2012篇 |
2015年 | 2346篇 |
2014年 | 3365篇 |
2013年 | 3959篇 |
2012年 | 3421篇 |
2011年 | 4084篇 |
2010年 | 3178篇 |
2009年 | 3155篇 |
2008年 | 2909篇 |
2007年 | 2636篇 |
2006年 | 2343篇 |
2005年 | 1916篇 |
2004年 | 1805篇 |
2003年 | 1509篇 |
2002年 | 1139篇 |
2001年 | 869篇 |
2000年 | 850篇 |
1999年 | 702篇 |
1998年 | 689篇 |
1997年 | 665篇 |
1996年 | 544篇 |
1995年 | 582篇 |
1994年 | 486篇 |
1993年 | 419篇 |
1992年 | 350篇 |
1991年 | 329篇 |
1990年 | 290篇 |
1989年 | 243篇 |
1988年 | 186篇 |
1987年 | 188篇 |
1986年 | 192篇 |
1985年 | 349篇 |
1984年 | 410篇 |
1983年 | 250篇 |
1982年 | 288篇 |
1981年 | 232篇 |
1980年 | 200篇 |
1979年 | 162篇 |
1978年 | 114篇 |
1977年 | 114篇 |
1976年 | 128篇 |
1975年 | 86篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
Thaís Pasqualli Pamella Eduardha E Chaves Lavínia da Veiga Pereira Élvio Adílio Serpa Luís Flávio Souza de Oliveira Michel Mansur Machado 《Clinical and experimental pharmacology & physiology》2020,47(10):1751-1757
One of the most widely used sweeteners in the world is sucralose. With sweetening power 600 times greater than sucrose, its use grows among those who seek to cut calories. Research shows that when heated, sucralose generates toxic products that attack the organism and interact with DNA. Our objective was to test this sweetener under unheated conditions and at average concentrations of consumption, evaluating parameters of cytotoxicity, genotoxicity, and immunotoxicity. For this purpose, we made use of lymphocyte cultures and the analysis of their CD3+, CD4+, and CD8+ subpopulations. In a complementary way, the mechanism of action is proposed here by computational methods. Our results showed that sucralose reduces non-selectively the total lymphocytes due to falls in the levels of the CD4+, CD8+, and CD4+CD8+ subpopulations. We observed an increase in the level of DNA damage and a gradual incidence of structural changes in the lymphocyte chromosomal sets. It was possible to propose that sucralose modulates the gene expression, interfering especially with the MAPK8, APTX, and EID1 genes. This article presents the results of an evidence-based approach to the safety of human health in the use of sucralose. Finally, this study points out that sucralose has cytotoxic, genotoxic, and mutagenic effects in the concentrations and conditions tested in human lymphocyte cell culture. 相似文献
994.
995.
996.
997.
Jingran Ji Woo Ram Park Soojeong Cho Yihe Yang Weiguo Li Kathleen Harris Xiaoke Huang Shangzhi Gu Dong-Hyun Kim Zhuoli Zhang Andrew C. Larson 《Journal of vascular and interventional radiology : JVIR》2019,30(7):1106-1115.e1
PurposeTo label Clostridium novyi-NT spores (C. novyi-NT) with iron oxide nanoclusters and track distribution of bacteria during magnetic resonance (MR) imaging-monitored locoregional delivery to liver tumors using intratumoral injection or intra-arterial transcatheter infusion.Materials and MethodsVegetative state C. novyi-NT were labeled with iron oxide particles followed by induction of sporulation. Labeling was confirmed with fluorescence microscopy and transmission electron microscopy (TEM). T2 and T2* relaxation times for magnetic clusters and magnetic microspheres were determined using 7T and 1.5T MR imaging scanners. In vitro assays compared labeled bacteria viability and oncolytic potential to unlabeled controls. Labeled spores were either directly injected into N1-S1 rodent liver tumors (n = 24) or selectively infused via the hepatic artery in rabbits with VX2 liver tumors (n = 3). Hematoxylin-eosin, Prussian blue, and gram staining were performed. Statistical comparison methods included paired t-test and ANOVA.ResultsBoth fluorescence microscopy and TEM studies confirmed presence of iron oxide labels within the bacterial spores. Phantom studies demonstrated that the synthesized nanoclusters produce R2 relaxivities comparable to clinical agents. Labeling had no significant impact on overall growth or oncolytic properties (P >.05). Tumor signal-to-noise ratio (SNR) decreased significantly following intratumoral injection and intra-arterial infusion of labeled spores (P <.05). Prussian blue and gram staining confirmed spore delivery.ConclusionsC. novyi-NT spores can be internally labeled with iron oxide nanoparticles to visualize distribution with MR imaging during locoregional bacteriolytic therapy involving direct injection or intra-arterial transcatheter infusion. 相似文献
998.
999.