全文获取类型
收费全文 | 94656篇 |
免费 | 4595篇 |
国内免费 | 327篇 |
专业分类
耳鼻咽喉 | 1162篇 |
儿科学 | 2715篇 |
妇产科学 | 2209篇 |
基础医学 | 13065篇 |
口腔科学 | 1797篇 |
临床医学 | 7564篇 |
内科学 | 23099篇 |
皮肤病学 | 2037篇 |
神经病学 | 8477篇 |
特种医学 | 3078篇 |
外国民族医学 | 32篇 |
外科学 | 11739篇 |
综合类 | 407篇 |
一般理论 | 23篇 |
预防医学 | 8400篇 |
眼科学 | 1586篇 |
药学 | 6284篇 |
中国医学 | 254篇 |
肿瘤学 | 5650篇 |
出版年
2023年 | 560篇 |
2022年 | 1009篇 |
2021年 | 2318篇 |
2020年 | 1207篇 |
2019年 | 2038篇 |
2018年 | 4184篇 |
2017年 | 2636篇 |
2016年 | 2001篇 |
2015年 | 2152篇 |
2014年 | 2821篇 |
2013年 | 4018篇 |
2012年 | 6154篇 |
2011年 | 6221篇 |
2010年 | 3364篇 |
2009年 | 2919篇 |
2008年 | 5331篇 |
2007年 | 5443篇 |
2006年 | 5150篇 |
2005年 | 5218篇 |
2004年 | 4916篇 |
2003年 | 4625篇 |
2002年 | 4403篇 |
2001年 | 2340篇 |
2000年 | 2468篇 |
1999年 | 2013篇 |
1998年 | 685篇 |
1997年 | 469篇 |
1996年 | 452篇 |
1995年 | 392篇 |
1994年 | 338篇 |
1993年 | 312篇 |
1992年 | 1060篇 |
1991年 | 909篇 |
1990年 | 899篇 |
1989年 | 812篇 |
1988年 | 719篇 |
1987年 | 740篇 |
1986年 | 648篇 |
1985年 | 594篇 |
1984年 | 435篇 |
1983年 | 350篇 |
1982年 | 215篇 |
1979年 | 309篇 |
1978年 | 227篇 |
1974年 | 242篇 |
1973年 | 242篇 |
1972年 | 239篇 |
1971年 | 233篇 |
1969年 | 208篇 |
1968年 | 208篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Jose M. Morales Jose Angel Martinez-Flores Manuel Serrano Maria José Castro Francisco Javier Alfaro Florencio García Miguel Angel Martínez Amado Andrés Esther González Manuel Praga Estela Paz-Artal Antonio Serrano 《Journal of the American Society of Nephrology : JASN》2015,26(3):735-745
In the current immunosuppressive therapy era, vessel thrombosis is the most common cause of early graft loss after renal transplantation. The prevalence of IgA anti–β2-glycoprotein I antibodies (IgA-aB2GPI-ab) in patients on dialysis is elevated (>30%), and these antibodies correlate with mortality and cardiovascular morbidity. To evaluate the effect of IgA-aB2GPI-ab in patients with transplants, we followed all patients transplanted from 2000 to 2002 in the Hospital 12 de Octubre prospectively for 10 years. Presence of IgA-aB2GPI-ab in pretransplant serum was examined retrospectively. Of 269 patients, 89 patients were positive for IgA-aB2GPI-ab (33%; group 1), and the remaining patients were negative (67%; group 2). Graft loss at 6 months post-transplant was significantly higher in group 1 (10 of 89 versus 3 of 180 patients in group 2; P=0.002). The most frequent cause of graft loss was thrombosis of the vessels, which was observed only in group 1 (8 of 10 versus 0 of 3 patients in group 2; P=0.04). Multivariate analysis showed that the presence of IgA-aB2GPI-ab was an independent risk factor for early graft loss (P=0.04) and delayed graft function (P=0.04). There were no significant differences regarding patient survival between the two groups. Graft survival was similar in both groups after 6 months. In conclusion, patients with pretransplant IgA-aB2GPI-ab have a high risk of early graft loss caused by thrombosis and a high risk of delayed graft function. Therefore, pretransplant IgA-aB2GPI-ab may have a detrimental effect on early clinical outcomes after renal transplantation. 相似文献
3.
4.
José A. Lorente Pablo Cardinal-Fernández Diego Muñoz Fernando Frutos-Vivar Arnaud W. Thille Carlos Jaramillo Aida Ballén-Barragán José M. Rodríguez Oscar Peñuelas Guillermo Ortiz José Blanco Bruno Valle Pinheiro Nicolás Nin María del Carmen Marin Andrés Esteban Taylor B. Thompson 《Intensive care medicine》2015,41(11):1921-1930
5.
6.
7.
8.
9.
Rènée du Toit Katherine Soong Garry Brian Jacqueline Ramke 《Optometry and vision science》2006,83(8):582-588
PURPOSE: The advantages of a focometer (FOCOMETER) over other methods of refraction for use in developing countries are that it is lightweight, compact, relatively inexpensive, fairly quick, and easy to use with minimal training. This clinical trial compared the repeatability, validity, and ease of use of the focometer with an autorefractor. METHODS: The refractive status of the right eye of 80 participants was determined with an autorefractor (Canon RK3). Three measurements were also taken with the focometer. RESULTS: The spherical equivalent (M) of the focometer was 0.25 D more positive than the autorefractor (p < 0.001) and 84% of measurements were within 0.75 D of the autorefractor. The autorefractor detected astigmatism in 91% (73) of the eyes, whereas the focometer identified only 32% (26). The design of the clock target restricts cylinder axis accuracy to the nearest 15 degrees . There was evidence of a learning effect for the focometer: the second and third measurements were more repeatable in the untrained group. There were no differences between the mean (1.03 +/- 2.28) and third focometer (-1.05 +/- 2.32) measurements (p = 0.34). However, using the third focometer measurement, 94% of participants had visual acuities of at least 6/12(-2). CONCLUSIONS: This study highlighted the focometer's restricted power range, inaccuracy of astigmatism and axis determination, and dependence on subject understanding and compliance. Therefore, in most clinical settings, the focometer would not be adequate for quantifying refractive error, but the focometer spherical equivalent was within acceptable limits of the autorefractor, and the visual acuity with lenses determined by the focometer indicates its potential usefulness in public health settings, especially where only spherical ready-made spectacles are dispensed. There may be more cost-effective ways to determine refractive error in these circumstances. A potentially important enhancement in focometer methodology that improves its ease of use was identified: use only the third measurement for each eye. 相似文献
10.
Mariela Dutra Gontijo Moura Soraya de Mattos Camargo Grossmann Linaena Méricy da Silva Fonseca Maria Inês Barreiros Senna Ricardo Alves Mesquita 《Journal of oral pathology & medicine》2006,35(6):321-326
BACKGROUND: Oral hairy leukoplakia (OHL) may be an indicator of the progression of Human Immunodeficiency Virus (HIV)-induced immuno-depression, and the evaluation of risk factors leading to OHL is important in the management of these HIV-infected patients. However, there are few studies that analyze risk factors leading to OHL in the Brazilian population. The aim of this case-control study is to present data about prevalence rates and risk factors leading to OHL in a sample of HIV-infected adults in Brazil. METHODS: This case-control study included 111 HIV-infected patients treated at a clinic for sexually transmitted diseases and HIV. In the initial examinations with dentists, variables were collected from all patients. Diagnosis of OHL was performed in accordance with the International Classification System and cytological features. The Fisher and the chi-squared tests were used for statistical analysis. The proportional prevalence and odds ratio were estimated. RESULTS: Outcome presented a positive, statistically significant association among the presence of OHL and viral load of 3000 copies/mul or greater (P = 0.0001; odds ratio (OR) = 5.8), presence of oral candidiasis (P = 0.0000; OR = 11.1), previous use of fluconazole (P = 0.0000; OR = 24.6), and use of systemic acyclovir (P = 0.032; OR = 4.3). Antiretroviral medication presented a negative, statistically significant association with the presence of OHL (P = 0.002; OR = 8.4). CONCLUSIONS: Prevalence of OHL was 28.8%. Viral load, oral candidiasis, previous use of fluconazole, and systemic acyclovir were determined to be risk factors for OHL. Antiretroviral medication proved to be protective against the development of OHL. 相似文献