全文获取类型
收费全文 | 1971篇 |
免费 | 129篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 83篇 |
儿科学 | 198篇 |
妇产科学 | 41篇 |
基础医学 | 191篇 |
口腔科学 | 120篇 |
临床医学 | 157篇 |
内科学 | 316篇 |
皮肤病学 | 34篇 |
神经病学 | 89篇 |
特种医学 | 115篇 |
外科学 | 231篇 |
综合类 | 27篇 |
预防医学 | 151篇 |
眼科学 | 13篇 |
药学 | 67篇 |
中国医学 | 5篇 |
肿瘤学 | 265篇 |
出版年
2023年 | 9篇 |
2022年 | 16篇 |
2021年 | 49篇 |
2020年 | 21篇 |
2019年 | 33篇 |
2018年 | 39篇 |
2017年 | 30篇 |
2016年 | 37篇 |
2015年 | 52篇 |
2014年 | 58篇 |
2013年 | 76篇 |
2012年 | 119篇 |
2011年 | 93篇 |
2010年 | 62篇 |
2009年 | 58篇 |
2008年 | 73篇 |
2007年 | 80篇 |
2006年 | 76篇 |
2005年 | 84篇 |
2004年 | 75篇 |
2003年 | 71篇 |
2002年 | 61篇 |
2001年 | 55篇 |
2000年 | 44篇 |
1999年 | 55篇 |
1998年 | 32篇 |
1997年 | 30篇 |
1996年 | 22篇 |
1995年 | 21篇 |
1994年 | 13篇 |
1993年 | 25篇 |
1992年 | 46篇 |
1991年 | 37篇 |
1990年 | 46篇 |
1989年 | 39篇 |
1988年 | 28篇 |
1987年 | 26篇 |
1986年 | 27篇 |
1985年 | 28篇 |
1984年 | 16篇 |
1983年 | 19篇 |
1982年 | 19篇 |
1981年 | 15篇 |
1980年 | 17篇 |
1978年 | 14篇 |
1977年 | 17篇 |
1976年 | 15篇 |
1974年 | 11篇 |
1973年 | 15篇 |
1972年 | 17篇 |
排序方式: 共有2103条查询结果,搜索用时 12 毫秒
61.
62.
目的:检测MCM5蛋白和PCNA在肺癌组织中的表达,探讨两者与肺癌各临床病理因素之间的关系及两者相互的联系,从而为评估肺癌的发生发展、预后及治疗提供理论依据。方法:运用免疫组织化学技术分别检测MCM5蛋白和PCNA在68例肺癌组织和20例正常组织中的表达情况,分析其与临床病理因素之间的关系及两者相互的联系。结果:MCM5表达的阳性信号位于细胞核,胞浆无着色。在正常肺组织中,MCM5的表达局限在上皮基底部的1/3至1/2的细胞,在肺癌组织中,MCM5的表达分布广泛,靠近上皮表面的细胞也可见大量表达。(1)正常肺组织和肺癌组织的MCM5的表达的差别有统计学意义(P<0.01)。(2)肺癌中MCM5表达与分化程度、淋巴结转移有显著相关性(P<0.05),与病人年龄、性别无显著相关性(P>0.05)。(3)PCNA的表达与肺癌的分化程度无显著相关性(P>0.05)。(4)在肺正常组织中,PCNA标记指数高于MCM5标记指数,两者具有显著差异性(P<0.05)。在肺癌组织中,PCNA与MCM5标记指数无显著差异性(P>0.05)。结论:(1)在肺组织中,微小染色体维持蛋白5(MCM5)是一种可靠的细胞增殖标志物。根据MCM5染色的组织结构差异和平均光密度能比较准确区分肺正常组织和癌组织。MCM5表达与肺癌的分化程度显著相关,因此MCM5表达可以提示肺癌的恶性程度,有助于临床判断病人的预后以及选择合适的治疗方法。MCM5与其他增殖标志PCNA相比是一种更好的细胞增殖标志物,是肺癌细胞的更好标志和分级指标。(2)PCNA在肺癌组织中过表达,提示PCNA的过表达与肺癌的发生发展关系密切。 相似文献
63.
Daniel R. Budman E. Bruce Merchant Alfred D. Steinberg Bernard Doft M. Eric Gershwin Elaine Lizzio J. Patton Reeves 《Arthritis \u0026amp; Rheumatology》1977,20(3):829-833
Thirty-seven patients with criteria for systemic lupus erythematosus (SLE) and 18 normal controls were studied for their spontaneous background IgM antibody plaque-forming cell number to specific chemical haptens. Active SLE patients had significantly more plaque-forming cells in their peripheral blood to a total of five chemical determinants than did patients with inactive disease or controls. This increased number of plaque forming-cells correlated with depressed serum C3 levels by Spearman rank-order analysis. The finding of elevated numbers of spontaneous IgM plaque-forming cells to defined chemical haptens supports the concept that active SLE demonstrates a generalized increase in B-cell activity toward a variety of antigens. 相似文献
64.
65.
66.
Beatriz Gómez-González Horacio Merchant LariosAlfonso Escobar 《International journal of developmental neuroscience》2011,29(8):839-846
Brain endothelial ultrastructural properties contribute to maintain proper blood-brain barrier (BBB) function. Several physiological and pathological conditions have been shown to alter BBB permeability to blood-borne molecules, acute and chronic stress among them. In the rat, early life stress increased transvascular transport of Evans blue, however, the route of tracer extravasation is not fully known; therefore the aim of the present experiment was to describe the ultrastructural changes in endothelial cells subsequent to chronic perinatal stress in order to ascertain the route for transvascular transport of an electrodense tracer. Pregnant Wistar rats and their litters were used. Four pregnant rats were subjected to forced swimming between gestational days 10 to 20. After delivery, half of the control litters underwent 180 min maternal separation from postnatal day 2 to 20. Controls were kept free of any stress manipulation. At sacrifice between postnatal days 1 to 30 subjects were given intracardially the lectin wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP). WGA-HRP stained hippocampi were processed for ultrastructural analysis, transmission electron micrographs were obtained and endothelial ultrastructural parameters quantified using the ImageJ software. Both stress procedures accelerated gross microvessel development by decreasing capillary wall thickness and endothelial microvilli. However, early-life stress also neutralized endothelial glycocalyx, increased vesicle-mediated transport and tended to promote the formation of secondary lysosomes containing endocytosed WGA-HRP vesicles, all parameters of altered endothelial cell function. Tight junction development in both stress groups was similar to the control pups. 相似文献
67.
MSTM Almeida SCB Lima LL Carvalho JVM Almeida LG Santos JRA Rolim TE Rocha 《Journal of cutaneous pathology》2010,37(11):1170-1173
Systemic sclerosis (SSc) is an autoimmune systemic disease characterized by small vessel involvement that leads to tissue ischemia and fibroblast stimulation resulting in accumulation of collagen (fibrosis) in the skin and internal organs. Lipomembranous panniculitis is a peculiar type of fat necrosis and has been reported with clinical conditions, commonly with peripheral vascular diseases. We describe a case of a 43‐year‐old woman with SSc manifestations, who presented with black scaly skin plaques, associated with thickening of the subcutaneous fat tissue, on the lateral surface of her thighs, her calves, gluteal area and lower abdomen. Biopsy revealed lipomembranous panniculitis. Lipomembranous changes have been seen in connective tissue disorders such as lupus profundus, morphea, systemic sclerosis and panniculitis associated with dermatomyositis, but rarely in thighs, calves, gluteal area and lower abdomen. Almeida MSTM, Lima SCB, Carvalho LL, Almeida JVM, Santos LG, Rolim JRA, Rocha TE. Panniculitis–An unusual cutaneous manifestation of systemic sclerosis. 相似文献
68.
69.
70.
Video as an Effective Method to Deliver Pretest Information for Rapid Human Immunodeficiency Testing
Roland C. Merchant MD MPH ScD Melissa A. Clark PhD Kenneth H. Mayer MD George R. Seage III MPH ScD Victor G. DeGruttola ScD Bruce M. Becker MD MPH 《Academic emergency medicine》2009,16(2):124-135
Objectives: Video‐based delivery of human immunodeficiency virus (HIV) pretest information might assist in streamlining HIV screening and testing efforts in the emergency department (ED). The objectives of this study were to determine if the video “Do you know about rapid HIV testing?” is an acceptable alternative to an in‐person information session on rapid HIV pretest information, in regard to comprehension of rapid HIV pretest fundamentals, and to identify patients who might have difficulties in comprehending pretest information. Methods: This was a noninferiority trial of 574 participants in an ED opt‐in rapid HIV screening program who were randomly assigned to receive identical pretest information from either an animated and live‐action 9.5‐minute video or an in‐person information session. Pretest information comprehension was assessed using a questionnaire. The video would be accepted as not inferior to the in‐person information session if the 95% confidence interval (CI) of the difference (Δ) in mean scores on the questionnaire between the two information groups was less than a 10% decrease in the in‐person information session arm’s mean score. Linear regression models were constructed to identify patients with lower mean scores based upon study arm assignment, demographic characteristics, and history of prior HIV testing. Results: The questionnaire mean scores were 20.1 (95% CI = 19.7 to 20.5) for the video arm and 20.8 (95% CI = 20.4 to 21.2) for the in‐person information session arm. The difference in mean scores compared to the mean score for the in‐person information session met the noninferiority criterion for this investigation (Δ = 0.68; 95% CI = 0.18 to 1.26). In a multivariable linear regression model, Blacks/African Americans, Hispanics, and those with Medicare and Medicaid insurance exhibited slightly lower mean scores, regardless of the pretest information delivery format. There was a strong relationship between fewer years of formal education and lower mean scores on the questionnaire. Age, gender, type of insurance, partner/marital status, and history of prior HIV testing were not predictive of scores on the questionnaire. Conclusions: In terms of patient comprehension of rapid HIV pretest information fundamentals, the video was an acceptable substitute to pretest information delivered by an HIV test counselor. Both the video and the in‐person information session were less effective in providing pretest information for patients with fewer years of formal education. 相似文献