首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   271篇
  免费   17篇
  288篇
  2023年   2篇
  2022年   4篇
  2021年   6篇
  2019年   2篇
  2018年   5篇
  2017年   3篇
  2016年   5篇
  2015年   5篇
  2014年   10篇
  2013年   12篇
  2012年   20篇
  2011年   11篇
  2010年   13篇
  2009年   11篇
  2008年   16篇
  2007年   7篇
  2006年   9篇
  2005年   7篇
  2004年   3篇
  2003年   5篇
  2002年   6篇
  2001年   12篇
  2000年   8篇
  1999年   6篇
  1998年   5篇
  1997年   4篇
  1996年   2篇
  1995年   4篇
  1993年   2篇
  1992年   3篇
  1991年   3篇
  1990年   4篇
  1989年   3篇
  1988年   7篇
  1987年   3篇
  1986年   4篇
  1985年   2篇
  1984年   2篇
  1972年   2篇
  1971年   2篇
  1970年   2篇
  1966年   3篇
  1963年   2篇
  1962年   3篇
  1950年   2篇
  1948年   2篇
  1938年   4篇
  1932年   3篇
  1908年   1篇
  1902年   2篇
排序方式: 共有288条查询结果,搜索用时 15 毫秒
61.
62.
63.
Accumulation of beta-amyloid (Aβ), produced by the proteolytic cleavage of amyloid precursor protein (APP) by β- and γ-secretase, is widely believed to be associated with Alzheimer’s disease (AD). Research around the high-throughput screening hit (S)-4-chlorophenylsulfonyl isoleucinol led to the identification of the Notch-1-sparing (9.5-fold) γ-secretase inhibitor (S)-N-(5-chlorothiophene-2-sulfonyl)-β,β-diethylalaninol 7.b.2 (Aβ 40/42 EC50 = 28 nM), which is efficacious in reduction of Aβ production in vivo.  相似文献   
64.
The genetic polymorphism that has the greatest impact on immune control of human immunodeficiency virus (HIV) infection is expression of HLA-B*57. Understanding of the mechanism for this strong effect remains incomplete. HLA-B*57 alleles and the closely related HLA-B*5801 are often grouped together because of their similar peptide-binding motifs and HIV disease outcome associations. However, we show here that the apparently small differences between HLA-B*57 alleles, termed HLA-B*57 micropolymorphisms, have a significant impact on immune control of HIV. In a study cohort of >2,000 HIV C-clade-infected subjects from southern Africa, HLA-B*5703 is associated with a lower viral-load set point than HLA-B*5702 and HLA-B*5801 (medians, 5,980, 15,190, and 19,000 HIV copies/ml plasma; P = 0.24 and P = 0.0005). In order to better understand these observed differences in HLA-B*57/5801-mediated immune control of HIV, we undertook, in a study of >1,000 C-clade-infected subjects, a comprehensive analysis of the epitopes presented by these 3 alleles and of the selection pressure imposed on HIV by each response. In contrast to previous studies, we show that each of these three HLA alleles is characterized both by unique CD8(+) T-cell specificities and by clear-cut differences in selection pressure imposed on the virus by those responses. These studies comprehensively define for the first time the CD8(+) T-cell responses and immune selection pressures for which these protective alleles are responsible. These findings are consistent with HLA class I alleles mediating effective immune control of HIV through the number of p24 Gag-specific CD8(+) T-cell responses generated that can drive significant selection pressure on the virus.  相似文献   
65.
66.

Introduction  

There is an ever-increasing need for animal models to evaluate efficacy and safety of new therapeutics in the field of rheumatoid arthritis (RA). Particularly for the early preclinical evaluation of human-specific biologicals targeting the progressive phase of the disease, there is a need for relevant animal models. In response to this requirement we set out to develop a model of collagen-induced arthritis (CIA) in a small-sized nonhuman primate species (300 to 400 g at adult age); that is, the common marmoset (Callithrix jacchus).  相似文献   
67.
The Stomach, Helicobacter pylori, and Acid Secretion   总被引:1,自引:0,他引:1  
Robert H. Riddell  MD 《Helicobacter》2006,11(6):592-593
  相似文献   
68.
Background: Failure to maintain weight losses in lifestyle change programs continues to be a major problem and warrants investigation of innovative approaches to weight control. Objective: The goal of this study was to compare two novel group interventions, both aimed at improving weight loss maintenance, with a control group. Methods and Procedures: A total of 103 women lost weight on a meal replacement‐supplemented diet and were then randomized to one of three conditions for the 14‐week maintenance phase: cognitive‐behavioral treatment (CBT); CBT with an enhanced food monitoring accuracy (EFMA) program; or these two interventions plus a reduced energy density eating (REDE) program. Assessments were conducted periodically through an 18‐month postintervention. Outcome measures included weight and self‐reported dietary intake. Data were analyzed using completers only as well as baseline‐carried‐forward imputation. Results: Participants lost an average of 7.6 ± 2.6 kg during the weight loss phase and 1.8 ± 2.3 kg during the maintenance phase. Results do not suggest that the EFMA intervention was successful in improving food monitoring accuracy. The REDE group decreased the energy density (ED) of their diets more so than the other two groups. However, neither the REDE nor the EFMA condition showed any advantage in weight loss maintenance. All groups regained weight between 6‐ and 18‐month follow‐ups. Discussion: Although no incremental weight maintenance benefit was observed in the EFMA or EFMA + REDE groups, the improvement in the ED of the REDE group's diet, if shown to be sustainable in future studies, could have weight maintenance benefits.  相似文献   
69.
Over 3500 patients with recent onset inflammatory polyarthritis (IP) have been recruited by the Norfolk Arthritis Register (NOAR) since 1990. Longitudinal data from this cohort have been used to examine the prevalence and predictors of remission, functional disability, radiological outcome, cardiovascular mortality and co-morbidity and the development of non-Hodgkin's lymphoma. Rheumatoid factor titre, high baseline C-reactive protein and high baseline HAQ score are all predictors of a poor outcome. There is a strong association between possession of the shared epitope and the development of erosions. Patients who satisfy the American College of Rheumatology criteria for rheumatoid arthritis (RA) have a worse prognosis than those who do not. However, it appears that these patients are a poorly defined subset of all those with IP rather than having an entirely separate disease entity. New statistical techniques offer exciting possibilities for using longitudinal datasets such as NOAR to explore the long-term effects of treatment in IP and RA.  相似文献   
70.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号