全文获取类型
收费全文 | 5433篇 |
免费 | 379篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 89篇 |
儿科学 | 141篇 |
妇产科学 | 129篇 |
基础医学 | 686篇 |
口腔科学 | 44篇 |
临床医学 | 437篇 |
内科学 | 1634篇 |
皮肤病学 | 105篇 |
神经病学 | 367篇 |
特种医学 | 204篇 |
外科学 | 667篇 |
综合类 | 19篇 |
一般理论 | 1篇 |
预防医学 | 462篇 |
眼科学 | 74篇 |
药学 | 249篇 |
中国医学 | 4篇 |
肿瘤学 | 519篇 |
出版年
2023年 | 23篇 |
2022年 | 58篇 |
2021年 | 150篇 |
2020年 | 90篇 |
2019年 | 173篇 |
2018年 | 150篇 |
2017年 | 130篇 |
2016年 | 111篇 |
2015年 | 121篇 |
2014年 | 168篇 |
2013年 | 243篇 |
2012年 | 384篇 |
2011年 | 374篇 |
2010年 | 230篇 |
2009年 | 213篇 |
2008年 | 318篇 |
2007年 | 337篇 |
2006年 | 299篇 |
2005年 | 276篇 |
2004年 | 260篇 |
2003年 | 234篇 |
2002年 | 238篇 |
2001年 | 93篇 |
2000年 | 120篇 |
1999年 | 117篇 |
1998年 | 63篇 |
1997年 | 48篇 |
1996年 | 56篇 |
1995年 | 46篇 |
1994年 | 36篇 |
1993年 | 25篇 |
1992年 | 76篇 |
1991年 | 68篇 |
1990年 | 69篇 |
1989年 | 46篇 |
1988年 | 46篇 |
1987年 | 41篇 |
1986年 | 35篇 |
1985年 | 30篇 |
1984年 | 33篇 |
1983年 | 13篇 |
1981年 | 12篇 |
1979年 | 29篇 |
1978年 | 16篇 |
1975年 | 11篇 |
1974年 | 15篇 |
1972年 | 12篇 |
1970年 | 10篇 |
1969年 | 13篇 |
1968年 | 16篇 |
排序方式: 共有5831条查询结果,搜索用时 15 毫秒
1.
2.
Ignasi Esteban Carmen Pastor-Quiones Lorena Usero Montserrat Plana Felipe García Lorna Leal 《Viruses》2021,13(3)
Over 36 million people worldwide are infected with HIV. Antiretroviral therapy (ART) has proven to be highly effective to prevent HIV-1 transmission, clinical progression and death. Despite this success, the number of HIV-1 infected individuals continues increasing and ART should be taken for life. Therefore, there are two main priorities: the development of preventive vaccines to protect from HIV acquisition and achieve an efficient control of HIV infection in the absence of ART (functional cure). In this sense, in the last few years, there has been a broad interest in new and innovative approaches such as mRNA-based vaccines. RNA-based immunogens represent a promising alternative to conventional vaccines because of their high potency, capacity for rapid development and potential for low-cost manufacture and safe administration. Some mRNA-based vaccines platforms against infectious diseases have demonstrated encouraging results in animal models and humans. However, their application is still limited because the instability and inefficient in vivo delivery of mRNA. Immunogens, design, immunogenicity, chemical modifications on the molecule or the vaccine delivery methods are all crucial interventions for improvement. In this review we, will present the current knowledge and challenges in this research field. mRNA vaccines hold great promises as part of a combined strategy, for achieving HIV functional cure. 相似文献
3.
4.
5.
6.
Bifid mandibular canal. 总被引:1,自引:0,他引:1
PURPOSE: To determine the incidence and characteristics of bifid mandibular canals. METHODS: A retrospective study was performed using panoramic radiographs of 2012 patients subjected to dental treatment in the Dental Clinic of the Valencia University Dental School (Valencia, Spain) between 1996 and 1999. The goal was to investigate the presence of double mandibular canals. RESULTS: The extraoral panoramic radiographs revealed a total of 7 images suggestive of bifid canals. Mandibular computed tomography revealed the existence of this anatomic variant in 2 of 3 patients. An analysis was performed on the incidence of this type of image in extraoral panoramic radiography, its possible interpretations, and the clinical implications of bifid mandibular canals. CONCLUSIONS: In this study, 0.35% of canals were bifid. All cases were in women. 相似文献
7.
8.
9.
Manuel Modolell Ines M. Corraliza Franz Link Germn Soler Klaus Eichmann 《European journal of immunology》1995,25(4):1101-1104
Activation with lipopolysaccharide induces macrophages to produce the enzymes arginase and nitric oxide (NO) synthase. Both enzymes use as a substrate the amino acid L-arginine, which can be either hydrolyzed by arginase to urea and ornithine or oxidized by NO synthase to NO and citrulline. NO is important in the bactericidal and cytotoxic activities of macrophages. An equivalent functional role of arginase and its products is not known. We tested the induction of arginase in bone marrow-derived macrophages by endogenous mediators that are known to induce NO synthase, such as interferon-γ (IFN-γ), or suppress the induction of this enzyme, such as interleukin (IL)-4, IL-10, and prostaglandin E2 (PGE2). We find that PGE2 and the TH2 cytokines IL-4 and IL-10 are potent inducers of arginase. In contrast, the TH 1 cytokine IFN-γ does not induce arginase. Simultaneous application of both types of mediators leads to reduced induction of both arginase and NO synthase. Exposure of macrophage cultures to inducers of NO synthase exhausts their ability to respond subsequently to inducers of arginase. Conversely, exposure of the cells to inducers of arginase exhausts their ability to respond subsequently to inducers of NO synthase. The results are consistent with a competition of both enzymes for their substrate, L-arginine, with a reciprocal inhibition in the induction of both enzymes, or a combination of both phenomena. The enzymes NO synthase and arginase appear to define two alternate functional states of macrophages, induced by TH 1 and TH 2 cytokines, respectively. 相似文献
10.