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   2349篇
  免费   242篇
  国内免费   13篇
耳鼻咽喉   17篇
儿科学   96篇
妇产科学   31篇
基础医学   335篇
口腔科学   39篇
临床医学   226篇
内科学   569篇
皮肤病学   49篇
神经病学   219篇
特种医学   175篇
外科学   218篇
综合类   43篇
一般理论   1篇
预防医学   147篇
眼科学   70篇
药学   86篇
中国医学   1篇
肿瘤学   282篇
  2021年   30篇
  2019年   23篇
  2018年   33篇
  2017年   20篇
  2016年   19篇
  2015年   33篇
  2014年   31篇
  2013年   61篇
  2012年   83篇
  2011年   91篇
  2010年   64篇
  2009年   64篇
  2008年   82篇
  2007年   95篇
  2006年   88篇
  2005年   92篇
  2004年   92篇
  2003年   100篇
  2002年   77篇
  2001年   81篇
  2000年   68篇
  1999年   64篇
  1998年   42篇
  1997年   47篇
  1996年   36篇
  1995年   34篇
  1994年   34篇
  1993年   18篇
  1992年   52篇
  1991年   45篇
  1990年   48篇
  1989年   49篇
  1988年   49篇
  1987年   67篇
  1986年   52篇
  1985年   67篇
  1984年   41篇
  1983年   47篇
  1982年   28篇
  1981年   25篇
  1980年   36篇
  1979年   42篇
  1978年   28篇
  1977年   37篇
  1976年   26篇
  1975年   30篇
  1974年   35篇
  1973年   31篇
  1972年   28篇
  1969年   20篇
排序方式: 共有2604条查询结果,搜索用时 15 毫秒
991.
Marrie RA, Horwitz RI, Cutter G, Tyry T, Vollmer T. Association between comorbidity and clinical characteristics of MS.
Acta Neurol Scand: 2011: 124: 135–141.
© 2010 John Wiley & Sons A/S. Background – Comorbidity may be associated with the clinical phenotype of disease and may affect prognostication and treatment decisions. Using the North American Research Committee on Multiple Sclerosis Registry, we described comorbidities present at onset and diagnosis of multiple sclerosis (MS) and examined whether comorbidities present at onset were associated with clinical course or age of MS symptom onset. Methods – In 2006, 8983 participants reported their physical and mental comorbidities; smoking status; height; and past and present weight. We compared clinical course at onset and age of symptom onset by comorbidity status. Results – At MS onset, a substantial proportion of participants had physical (24%) or mental (8.4%) comorbidities. The mean (SD) age of MS onset was 31.2 (9.0) years. Vascular, autoimmune, cancer, visual, and musculoskeletal comorbidities were associated with a later age of symptom onset. Among men and women, the odds of a relapsing course at onset were increased if mental comorbidities (OR 1.48; 1.08–2.01) were present at symptom onset. In women, gastrointestinal comorbidities (OR 1.78; 1.25–2.52) and obesity (OR 2.08 1.53–2.82) at MS onset were also associated with a relapsing course at onset. Conclusions – Comorbidity is frequently present at onset of MS and is associated with differences in clinical characteristics.  相似文献   
992.
993.
994.
Mucopolysaccharidosis VI (MPS VI, Maroteaux-Lamy Syndrome) is one of approximately 50 known lysosomal storage disorders. MPS VI is characterized by an absence or deficiency of N-acetylgalactosamine 4-sulfatase (arylsulfatase B) resulting in accumulation of dermatan sulfate. Prior to the availability of enzyme replacement therapy (ERT), the clinical management of MPS VI was limited to supportive care and allogeneic hematopoietic stem cell transplantation (HSCT); however, due to the rarity of this disease, little is known about the long-term outcomes of HSCT for MPS VI. The following retrospective study was performed using aggregate data gathered by the Center for International Blood and Marrow Transplant Research (CIBMTR) between 1982 and 2007 to determine survival probability for patients with MPS VI following allogeneic HSCT. This analysis identified 45 MPS VI patients with a median age of 5 years (range, 1-22 years) at the time they received an allogeneic HSCT. Cumulative incidence (95% CI) of acute graft-vs.-host disease at 100 days was 36% (21-53%). Probability of survival was 78% (65-89%) at 100 days and 66% (52-79%) at 1 and 3 years. While these data are based upon small numbers of recipients, they represent the largest series to date and may help clinicians assess the relative risks and benefits of currently available therapies.  相似文献   
995.
996.
997.
Regulatory T cells control the reactivity of potentially harmful, self-reactive T cells and prevent autoimmune diseases. Significant progress has been made in the identification, derivation, and mechanism of action of T regulatory cells, previously called suppressor T cells. Heterogeneous T regulatory subsets can be grouped into naturally occurring and those induced in the periphery. Here, we consider whether we can harness T regulatory cells to function as a therapeutic agent for patients with established autoimmune diseases. Since the principal function of thymus-derived, natural CD4+CD25+ cells is to prevent autoimmunity, this subset would be an obvious choice. Besides their contact-dependent, cytokine-independent mechanism of action, they can also induce other CD4+ cells to become suppressor cells. However, only few natural CD4+CD25+ cells circulate in human peripheral blood. Alternatively, one can use IL-2 and TGF-beta to generate large numbers of CD4+CD25+ regulatory T cells ex vivo from naive T cells. These cells have the phenotypic and functional properties similar to natural CD4+CD25+ cells, including the capacity to induce CD4+CD25- cells to develop suppressive activity. These natural-like CD4+CD25+ regulatory T cells are the product of separate effects of IL-2 and TGF-beta on both natural CD4+CD25+ and CD4+CD25- cells. The ability of natural-like CD4+CD25+ cells to induce other CD4+CD25- cells to develop suppressive activity is both contact-dependent and cytokine-dependent. Thus, the effects of IL-2 and TGF-beta on both natural CD4+CD25+ cells and CD4+CD25- cells may trigger a continuous loop which results in the renewal of antigen-specific CD4+ regulatory T cells. These studies suggest that the adoptive transfer of CD4+ T regulatory cells generated ex vivo with IL-2 and TGF-beta as a treatment for autoimmune diseases may have sustained, long-term beneficial effects.  相似文献   
998.
We assessed whether sociodemographic and clinical characteristics were determinants of clinical trial participation in the Women's Estrogen for Stroke Trial (WEST) by examining data collected on women with a WEST consent visit completed after June 1996. We found no differences in consent rates by education or ethnic group (32% of white women compared with 34% of black women). Conditions associated with the intervention, such as a history of hysterectomy or previous estrogen replacement use, were strongly associated with a woman's decision to participate in this clinical trial. In multivariate models, features independently associated with consent to participate were age (odds ratio [OR] 0.96, 95% confidence interval [CI] 0.94-0.97), hysterectomy (OR 1.78, 95% CI 1.27-2.50), no cognitive impairment (OR 1.70, 95% CI 1.10-2.63), history of volunteerism (OR 1.62, 95% CI 1.02-2.63), and previous estrogen use (RR 1.58, 95% CI 1.08-2.30).  相似文献   
999.
1000.
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