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   383篇
  免费   49篇
  国内免费   7篇
耳鼻咽喉   1篇
儿科学   18篇
妇产科学   5篇
基础医学   32篇
口腔科学   16篇
临床医学   56篇
内科学   104篇
皮肤病学   1篇
神经病学   25篇
特种医学   56篇
外科学   27篇
综合类   4篇
一般理论   1篇
预防医学   49篇
眼科学   1篇
药学   22篇
肿瘤学   21篇
  2021年   6篇
  2019年   4篇
  2018年   9篇
  2017年   4篇
  2016年   8篇
  2015年   6篇
  2014年   9篇
  2013年   14篇
  2012年   13篇
  2011年   14篇
  2010年   11篇
  2009年   12篇
  2008年   10篇
  2007年   19篇
  2006年   9篇
  2005年   14篇
  2004年   13篇
  2003年   20篇
  2002年   5篇
  2001年   11篇
  2000年   7篇
  1999年   10篇
  1998年   14篇
  1997年   8篇
  1996年   11篇
  1995年   7篇
  1994年   20篇
  1993年   13篇
  1992年   10篇
  1991年   13篇
  1990年   8篇
  1989年   12篇
  1988年   9篇
  1987年   14篇
  1986年   9篇
  1985年   9篇
  1984年   3篇
  1983年   3篇
  1982年   6篇
  1981年   7篇
  1980年   5篇
  1978年   5篇
  1977年   5篇
  1976年   2篇
  1975年   4篇
  1974年   4篇
  1968年   2篇
  1954年   1篇
  1936年   1篇
  1913年   1篇
排序方式: 共有439条查询结果,搜索用时 15 毫秒
1.
2.
3.
OBJECTIVE: Pancreatic cancer is known to aggregate in some families and has been associated with a wide variety of cancer syndromes. The authors describe their experience with pancreatic cancer and the range of associated cancer syndromes. METHODS: The charts of all patients seen for concern of a hereditary cancer syndrome in the Cancer Genetics Clinic at the University of Alberta between 1995 and 2002 were reviewed. RESULTS: Forty families reported a personal or family history of pancreatic cancer in the context of a possible hereditary cancer syndrome. Three additional families reported a history of pancreatitis. Twenty-four (56%) of those families were suspected of having a hereditary breast and ovarian cancer syndrome. A further seven (16%) were suspected of having hereditary nonpolyposis colon cancer. Only three (7%) were believed to be at risk for a site-specific pancreatic cancer syndrome. Another three (7%) were suspicious for hereditary pancreatitis. The remaining family histories were suggestive of Li-Fraumeni syndrome, von Hippel-Lindau syndrome or a nonspecific cancer predisposition. CONCLUSIONS: With such a wide variety of hereditary cancer syndromes associated with pancreatic cancer, an accurate assessment of the family history is essential to determine the most appropriate cancer screening for at-risk family members and to guide any molecular testing that may be offered.  相似文献   
4.
106 unicondylar knee replacement tibial components were retrieved and analyzed for the amount and type of polyethylene wear. Three different designs were retrieved which had essentially the same femorotibial conformity. Each design showed a characteristic failure pattern. The polyethylene of PCA tibial components showed serious delamination after only short durations, as a result of heat pressing. St Georg sledge prostheses showed some delamination after 4 years' duration due to sub-surface cracks which were initiated by fusion defects in the polyethylene; metal backing of the components did not affect delamination of this prosthesis. The Marmor designs showed the least wear, with shiny depressions and surface pitting; no delamination was observed in the Marmor prosthesis. Molecular weight determination by gel permeation chromatography and analysis of crystallinity using Fourier transformation infra-red spectroscopy demonstrated that St George polyethylene had higher molecular weight and crystallinity than Marmor polyethylene. In some of the components investigated, crystallinity and molecular weight of the polyethylene were reduced under the wear track when compared with the unworn polyethylene. Since fusion defects may cause delamination of polyethylene we urge manufacturers to reduce the number of such defects.  相似文献   
5.
6.
7.
Induction of mucosal tolerance by inhalation of soluble peptides with defined T cell epitopes is receiving much attention as a means of specifically down-regulating pathogenic T cell reactivities in autoimmune and allergic disorders. Experimental autoimmune encephalomyelitis (EAE) induced in the Lewis rat by immunization with myelin basic protein (MBP) and Freund's adjuvant (CFA) is mediated by CD4+ T cells specific for the MBP amino acid sequences 68-86 and 87-99. To further define the principles of nasal tolerance induction, we generated three different MBP peptides (MBP 68-86, 87-99 and the non- encephalitogenic peptide 110-128), and evaluated whether their nasal administration on day -11, -10, -9, -8 and -7 prior to immunization with guinea pig MBP (gp-MBP) + CFA confers protection to Lewis rat EAE. Protection was achieved with the encephalitogenic peptides MBP 68-86 and 87-99, MBP 68-86 being more potent, but not with MBP 110-128. Neither MBP 68-86 nor 87-99 at doses used conferred complete protection to gp-MBP-induced EAE. In contrast, nasal administration of a mixture of MBP 68-86 and 87-99 completely blocked gp-MBP-induced EAE even at lower dosage compared to that being used for individual peptides. Rats tolerized with MBP 68-86 + 87-99 nasally showed decreased T cell responses to MBP reflected by lymphocyte proliferation and IFN-gamma ELISPOT assays. Rats tolerized with MBP 68-86 + 87-99 also had abrogated MBP-reactive IFN-gamma and tumor necrosis factor-alpha mRNA expression in lymph node cells compared to rats receiving MBP 110-128 nasally, while similar low levels of MBP-reactive transforming growth factor-beta and IL-4 mRNA expressing cells were observed in the two groups. Nasal administration of MBP 68-86 + 87-99 only slightly inhibited guinea pig spinal cord homogenate-induced EAE, and passive transfer of spleen mononuclear cells from MBP 68-86 + 87-99-tolerized rats did not protect naive rats from EAE. Finally, we show that nasal administration of MBP 68-86 + 87-99 can reverse ongoing EAE induced with gp-MBP, although higher doses are required compared to the dosage needed for prevention. In conclusion, nasal administration of encephalitogenic MBP peptides can induce antigen-specific T cell tolerance and confer incomplete protection to gp-MBP-induced EAE, and MBP 68-86 and 87-99 have synergistic effects. Non-regulatory mechanisms are proposed to be responsible for tolerance development after nasal peptide administration.   相似文献   
8.
The dietitian plays a leadership role in improving the quality of life of nursing home residents. A better understanding of this role can strengthen practice in this area. This paper attempts to define the role of the dietitian in the nutritional care of the elderly in long-term care facilities. The impact of poor appetites, extended stays and nutrient requirements on menu planning and recipe development are discussed. Resident empowerment, improvement of the dining environment, evaluation of eating skills, and eating rehabilitation are proposed as new roles for the dietitian in the promotion of food consumption. The characteristics of nutritional assessment and therapeutic diets as they relate to long-term geriatric care are discussed.  相似文献   
9.
10.
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