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   1277篇
  免费   100篇
  国内免费   3篇
耳鼻咽喉   17篇
儿科学   97篇
妇产科学   21篇
基础医学   210篇
口腔科学   13篇
临床医学   138篇
内科学   284篇
皮肤病学   22篇
神经病学   93篇
特种医学   28篇
外科学   116篇
综合类   7篇
预防医学   104篇
眼科学   16篇
药学   71篇
中国医学   1篇
肿瘤学   142篇
  2023年   15篇
  2022年   20篇
  2021年   37篇
  2020年   17篇
  2019年   46篇
  2018年   46篇
  2017年   30篇
  2016年   37篇
  2015年   36篇
  2014年   45篇
  2013年   74篇
  2012年   98篇
  2011年   115篇
  2010年   50篇
  2009年   51篇
  2008年   97篇
  2007年   72篇
  2006年   86篇
  2005年   73篇
  2004年   58篇
  2003年   66篇
  2002年   40篇
  2001年   4篇
  2000年   7篇
  1999年   6篇
  1998年   6篇
  1997年   13篇
  1996年   8篇
  1995年   9篇
  1994年   4篇
  1993年   5篇
  1992年   10篇
  1991年   12篇
  1990年   7篇
  1989年   6篇
  1988年   8篇
  1987年   4篇
  1985年   3篇
  1983年   3篇
  1982年   3篇
  1979年   3篇
  1978年   2篇
  1977年   4篇
  1976年   2篇
  1974年   2篇
  1972年   11篇
  1971年   2篇
  1969年   5篇
  1968年   6篇
  1966年   2篇
排序方式: 共有1380条查询结果,搜索用时 15 毫秒
81.
The authors report their experience in preschool vision screening in the east of France, involving the Mother and Child Welfare Service and the School Health Service, under the administration of the National Ministry of Education. The review underlines the importance of early diagnosis of visual disorders in children before they reach three years of age. They recommend screening of every child at least once before the age of four years.  相似文献   
82.
83.
84.
We have proposed earlier that the poor capacity of the lipocalin allergen Bos d 2 to stimulate highly allergic subjects' peripheral blood mononuclear cells could be ascribed to endogenous lipocalins and could be related to the allergenic potential of the molecule. Here, we have characterized the proliferative and cytokine responses of human T cell clones against the immunodominant epitope of Bos d 2. We observed, for clone F1-9, that a substitution of aspartic acid for asparagine in the core region of the epitope increased the stimulatory capacity of the peptide about 100-fold in comparison with the natural peptide. For clone K3-2, from a different patient, the substitution of lysine for glutamine or isoleucine for leucine in the core region resulted in about 30-fold and 10-fold increases in the stimulatory capacity of the peptides, respectively. The clones also recognized self-protein-derived peptides but not the peptides derived from other lipocalins. We suggest that the poor recognition of the immunodominant epitope of Bos d 2 can be a factor accounting for Bos d 2-allergic subjects' weak cellular responses. Suboptimal recognition of self and allergen epitopes by T cells may be of significance for the allergenicity of proteins.  相似文献   
85.
86.
87.
88.
Experiments in mice and recent human clinical studies have clearly shown the contribution of CD8+ T lymphocyte in the control of tumor development. CD8+ T lymphocytes are a constitutive component of the immune response during the development of cancer. In murine models, the efficiency of various cancer vaccines mainly depends on their ability to induce CD8+ T lymphocytes. Clinical responses in immunotherapy treated cancer patients have been associated with the presence of antitumor specific CD8+ T lymphocytes. In spontaneous regressive melanomas, intratumor antigen specific CD8+ cytotoxic T cells were expanded suggesting their involvement in the tumor shrinkage. Administration of antitumor specific cytotoxic T clones in mice resulted in antitumor responses which directly demonstrated the therapeutic efficiency of these cells. However, in most cases during cancer progression, the presence of antitumor CD8 T lymphocyte is not associated with clinical responses. Intrinsic functional abnormalities of these cells or a defect of CD8+ T cell migration to the tumor may in part explain their failure to inhibit tumor development. On the other hand, tumors also develop immune escape mechanisms (down modulation of tumor antigens, secretion of immunosuppressive factors, expression of anti-apoptotic molecules by the tumors, or pro-apoptotic factors inducing T cell death) to resist to the CD8+ T cell attack. To circumvent these tumor escape mechanisms, efficient cancer vaccines will have to recruit CD8+ T cells associated with other immune effectors.  相似文献   
89.
A cohort of 215 sarcoidosis patients from the ACCESS study underwent a clinical evaluation at study enrollment and two years later. Approximately 80% of subjects had an improved or stable FVC, FEV1, chest radiograph determined by Scadding stage, and dyspnea scale. African-Americans had less improvement in FVC than Caucasians (p = 0.04). Patients with erythema nodosum at presentation were more likely to have improvement in the chest radiograph at two-year follow-up (p = 0.007). Patients with a lower annual family income were more likely to worsen with respect to dyspnea (p = 0.01) and more likely to have new organ involvement at two-year follow-up (p = 0.045). The development of new organ involvement over the two year follow-up period was more common in African-Americans compared to Caucasians (p = 0.002) and more likely in those with extrapulmonary involvement at study entry (p = 0.003). There was an excellent concordance between changes in FVC and FEV1 over the two-year period. However, changes in FVC alone were inadequate to describe the change in pulmonary status of the patients, as changes in chest radiographic findings or the level of dyspnea did often but not always move in the same direction as FVC. In conclusion, data from this heterogeneous United States sarcoidosis population indicate that sarcoidosis tends to improve or remain stable over two years in the majority of patients. Several factors associated with improved or worse outcome over two years were identified.  相似文献   
90.
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