全文获取类型
收费全文 | 29347篇 |
免费 | 1415篇 |
国内免费 | 195篇 |
专业分类
耳鼻咽喉 | 322篇 |
儿科学 | 544篇 |
妇产科学 | 703篇 |
基础医学 | 3402篇 |
口腔科学 | 1522篇 |
临床医学 | 2232篇 |
内科学 | 7934篇 |
皮肤病学 | 443篇 |
神经病学 | 2726篇 |
特种医学 | 1112篇 |
外科学 | 4236篇 |
综合类 | 112篇 |
一般理论 | 7篇 |
预防医学 | 1555篇 |
眼科学 | 434篇 |
药学 | 1617篇 |
中国医学 | 119篇 |
肿瘤学 | 1937篇 |
出版年
2023年 | 175篇 |
2022年 | 418篇 |
2021年 | 804篇 |
2020年 | 456篇 |
2019年 | 632篇 |
2018年 | 819篇 |
2017年 | 575篇 |
2016年 | 697篇 |
2015年 | 803篇 |
2014年 | 1106篇 |
2013年 | 1491篇 |
2012年 | 2278篇 |
2011年 | 2445篇 |
2010年 | 1406篇 |
2009年 | 1247篇 |
2008年 | 2125篇 |
2007年 | 2180篇 |
2006年 | 2009篇 |
2005年 | 2019篇 |
2004年 | 1794篇 |
2003年 | 1552篇 |
2002年 | 1441篇 |
2001年 | 183篇 |
2000年 | 118篇 |
1999年 | 164篇 |
1998年 | 240篇 |
1997年 | 189篇 |
1996年 | 184篇 |
1995年 | 144篇 |
1994年 | 132篇 |
1993年 | 91篇 |
1992年 | 91篇 |
1991年 | 84篇 |
1990年 | 68篇 |
1989年 | 69篇 |
1988年 | 68篇 |
1987年 | 50篇 |
1986年 | 50篇 |
1985年 | 41篇 |
1984年 | 84篇 |
1983年 | 54篇 |
1982年 | 72篇 |
1981年 | 45篇 |
1980年 | 27篇 |
1979年 | 24篇 |
1978年 | 26篇 |
1977年 | 30篇 |
1976年 | 21篇 |
1974年 | 16篇 |
1973年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Angela Mauro Salvatore Mauro Roberto Rega Luigi Martemucci Rita Sottile 《Pediatric dermatology》2019,36(1):e34-e36
Henoch‐Schonlein purpura (HSP) is the most common systemic vasculitis in childhood. There is no consensus about the management for isolated cutaneous manifestations in HSP. We describe a case of HSP presenting with severe skin lesions that did not respond to standard therapy with corticosteroids. The 11‐year‐old child was treated with intravenous immunoglobulins, which induced rapid and persistent resolution of symptomatology. 相似文献
2.
A growing body of data suggests that therapies based on Toll-like receptors (TLR) targeting, in particular TLR4, holds promise in curing autoimmune and inflammatory pathologies still lacking specific treatment, included several rare diseases. While TLR4 activators (agonists) have already found successful clinical application as vaccine adjuvants, the use of TLR4 blockers (antagonists) as antisepsis agents or as agents against inflammatory diseases (including arthritis, multiple sclerosis, neuroinflammations) and cancer is still at a preclinical phase of development. This minireview focuses on recent achievements on the development of TLR4 modulators based on lipid A structure simplification, in particular on compounds having disaccharide or monosaccharide structures. As the TLR4 activity of natural TLR4 ligands (lipopolysaccharide, LPS and its biologically active part, the lipid A) depends on both the structure of endotoxin aggregates in solution and on single-molecule interaction with MD-2 and CD14 receptors, the rational design of TLR4 modulators should in principle take into account both these factors. In the light of the most recent advances in the field, in this minireview we discuss the structure–activity relationship in simplified lipid A analogs, with cationic or anionic amphiphilic structures. 相似文献
3.
4.
5.
Melatonin reduces oxidative stress and improves vascular function in pulmonary hypertensive newborn sheep 下载免费PDF全文
Flavio Torres Alejandro González‐Candia Camilo Montt Germán Ebensperger Magdalena Chubretovic María Serón‐Ferré Roberto V. Reyes Aníbal J. Llanos Emilio A. Herrera 《Journal of pineal research》2015,58(3):362-373
Pulmonary hypertension of the newborn (PHN) constitutes a critical condition with severe cardiovascular and neurological consequences. One of its main causes is hypoxia during gestation, and thus, it is a public health concern in populations living above 2500 m. Although some mechanisms are recognized, the pathophysiological facts that lead to PHN are not fully understood, which explains the lack of an effective treatment. Oxidative stress is one of the proposed mechanisms inducing pulmonary vascular dysfunction and PHN. Therefore, we assessed whether melatonin, a potent antioxidant, improves pulmonary vascular function. Twelve newborn sheep were gestated, born, and raised at 3600 meters. At 3 days old, lambs were catheterized and daily cardiovascular measurements were recorded. Lambs were divided into two groups, one received daily vehicle as control and another received daily melatonin (1 mg/kg/d), for 8 days. At 11 days old, lung tissue and small pulmonary arteries (SPA) were collected. Melatonin decreased pulmonary pressure and resistance for the first 3 days of treatment. Further, melatonin significantly improved the vasodilator function of SPA, enhancing the endothelial‐ and muscular‐dependent pathways. This was associated with an enhanced nitric oxide‐dependent and nitric oxide independent vasodilator components and with increased nitric oxide bioavailability in lung tissue. Further, melatonin reduced the pulmonary oxidative stress markers and increased enzymatic and nonenzymatic antioxidant capacity. Finally, these effects were associated with an increase of lumen diameter and a mild decrease in the wall of the pulmonary arteries. These outcomes support the use of melatonin as an adjuvant in the treatment for PHN. 相似文献
6.
7.
8.
Phenotypic and genetic features of enteropathogenic Escherichia coli isolates from diarrheal children in the Ribeirão Preto metropolitan area,São Paulo State,Brazil 下载免费PDF全文
André Pitondo‐Silva Gerson Nakazato Juliana P. Falcão Kinue Irino Roberto Martinez Ana Lúcia C. Darini Rodrigo Tavanelli Hernandes 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2015,123(2):128-135
This study was designed to characterize a collection of 60 enteropathogenic Escherichia coli (EPEC) isolates from diarrheic feces of patients in the Ribeirão Preto metropolitan area regarding different phenotypic and molecular features. We examined antibiotic resistance profiles, occurrence of virulence factors‐encoding genes, intimin subtypes and the correlation of serotypes among typical (tEPEC) and atypical (aEPEC) EPEC isolates. The results demonstrated that atypical EPEC was more heterogeneous than typical EPEC concerning the characteristics investigated and 45.2% do not belong to classical EPEC serogroups. Intimin subtype β was the most frequent among the EPEC isolates (46.7%), being detected in both tEPEC and aEPEC. The majority of aEPEC isolates presented localized adherence‐like (LAL) pattern to HEp‐2 cells, although aEPEC isolates displaying diffuse adherence (DA) or non‐adherent were also detected. High prevalence of antimicrobial resistance was found for ampicillin, cephalothin, sulfonamide and tetracycline. In general, tEPEC isolates were more resistant to the antimicrobials tested than aEPEC isolates. 相似文献
9.
MEMRI and tumors: a method for the evaluation of the contribution of Mn(II) ions in the extracellular compartment 下载免费PDF全文
Eliana Gianolio Francesca Arena Enza Di Gregorio Roberto Pagliarin Martina Delbianco Gabriella Baio Silvio Aime 《NMR in biomedicine》2015,28(9):1104-1110
The purpose of the work was to set‐up a simple method to evaluate the contribution of Mn2+ ions in the intra‐ and extracellular tumor compartments in a MEMRI experiment. This task has been tackled by “silencing” the relaxation enhancement arising from Mn2+ ions in the extracellular space. In vitro relaxometric measurements allowed assessment of the sequestering activity of DO2A (1,4,7,10‐tetraazacyclododecane‐1,7‐diacetic acid) towards Mn2+ ions, as the addition of Ca‐DO2A to a solution of MnCl2 causes a drop of relaxivity upon the formation of the highly stable and low‐relaxivity Mn‐DO2A. It has been proved that the sequestering ability of DO2A towards Mn2+ ions is also fully effective in the presence of serum albumin. Moreover, it has been shown that Mn‐DO2A does not enter cell membranes, nor does the presence of Ca‐DO2A in the extracellular space prompt migration of Mn ions from the intracellular compartment. On this basis the in vivo, instantaneous, drop in SE% (percent signal enhancement) in T1‐weighted images is taken as evidence of the sequestration of extracellular Mn2+ ions upon addition of Ca‐DO2A. By applying the method to B16F10 tumor bearing mice, T1 decrease is readily detected in the tumor region, whereas a negligible change in SE% is observed in kidneys, liver and muscle. The relaxometric MRI results have been validated by ICP‐MS measurements. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
10.
Roberto V.P. Ribeiro Mitesh V. Badiwala Danny Ramzy Laura C. Tumiati Vivek Rao 《The Journal of thoracic and cardiovascular surgery》2019,157(2):615-625.e1