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   41398篇
  免费   3772篇
  国内免费   57篇
耳鼻咽喉   336篇
儿科学   1271篇
妇产科学   1114篇
基础医学   5540篇
口腔科学   597篇
临床医学   5016篇
内科学   7978篇
皮肤病学   455篇
神经病学   4255篇
特种医学   1140篇
外科学   5030篇
综合类   738篇
一般理论   95篇
预防医学   5241篇
眼科学   519篇
药学   2474篇
中国医学   21篇
肿瘤学   3407篇
  2023年   367篇
  2022年   565篇
  2021年   1219篇
  2020年   768篇
  2019年   1191篇
  2018年   1223篇
  2017年   926篇
  2016年   1001篇
  2015年   1039篇
  2014年   1375篇
  2013年   2015篇
  2012年   2922篇
  2011年   2924篇
  2010年   1538篇
  2009年   1392篇
  2008年   2301篇
  2007年   2266篇
  2006年   2232篇
  2005年   2175篇
  2004年   1936篇
  2003年   1686篇
  2002年   1553篇
  2001年   728篇
  2000年   746篇
  1999年   716篇
  1998年   421篇
  1997年   310篇
  1996年   290篇
  1995年   244篇
  1994年   236篇
  1993年   229篇
  1992年   459篇
  1991年   444篇
  1990年   437篇
  1989年   444篇
  1988年   359篇
  1987年   364篇
  1986年   354篇
  1985年   336篇
  1984年   281篇
  1983年   229篇
  1982年   194篇
  1981年   180篇
  1980年   144篇
  1979年   221篇
  1978年   188篇
  1977年   150篇
  1974年   181篇
  1973年   142篇
  1972年   157篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
A 66-year-old woman presented with an alien limb syndrome without dementia. The course of her illness was unremitting and at autopsy 6 years later her diagnosis was confirmed as corticobasal degeneration without Alzheimer-type pathology. Although the presence of ballooned achromatic cortical neurons and cell loss from the substantia nigra distinguishes such patients, the site and density of achromatic neurons has not previously been quantified. We show that immunohistochemistry for the cell stress protein ubiquitin selectively stains these achromatic neurons, whereas they do not stain for abnormally phosphorylated tau protein. Phosphorylated neurofilament antibodies recognise both ballooned and non-ballooned neurons. In this case, high densities of ubiquitin-positive ballooned neurons were found in frontal cortical regions with the highest densities in layers V and VI of the anterior cingulate cortex. In addition, high densities of ubiquitin-positive ballooned neurons were found in the insular cortex, claustrum and amygdala. These results confirm past reports of frontal pathology, but show that there is also considerable pathology in insular and parahippocampal cortical regions and some subcortical regions. Our findings suggest that the distribution and staining characteristics of ballooned neurons in corticobasal degeneration may help to differentiate these cases pathologically, while the absence of dementia appears to be an important clinical criterion.  相似文献   
62.
This article identifies common characteristics of educationally related programs that form a common basis for understanding and working with gifted programs. Special approaches and programs for educational enrichment as well as specific activities that have been successful are discussed.  相似文献   
63.
64.
65.
66.
67.
68.
In a survey of the 50 State health agencies in the spring of 1992, officials were asked about their manpower and research needs in the specific areas of administration, behavioral and social science, education and information, environmental health, environmental protection, epidemiology, laboratory, law, occupational health, policy and planning, and statistics. In all, 40 agencies (80 percent) responded. Indepth telephone interviews to determine whether universities and schools and graduate programs in public health filled these needs completed the data collection process. Agency officials indicated that their resources were least adequate in environmental protection, behavioral and social science, and occupational health. They did not feel their research needs were being met. There was a general feeling that universities and schools and programs in public health have different agendas than State agencies and that practical solutions to the shortage of research resources are not forthcoming from these sources. Suggestions are made as to what can be done to improve relationships between those who train public health personnel and those who employ them.  相似文献   
69.
Current immunosuppressive regimens for clinical transplantation are immunologically non-specific, are associated with acute and chronic toxic side-effects [1] and are unable to prevent chronic graft loss in a significant proportion of patients. Additionally, new and increasingly powerful drugs are being introduced to induce non-specific immunosuppression, and therefore this is likely to be followed by an increase in related complications such as the induction of cancers. Hence, there is a need for an alternative approach. It has been shown that long-term survival of murine cardiac grafts can be induced by the monoclonal antibody YIS 191 that depletes CD4 +T cells in vivo [2]. In this study, we have investigated the ability of a non-depleting antibody to produce better graft survival.  相似文献   
70.
A 59-year-old male presented with systemic mastocytosis with extensive skeletal involvement resulting in vertebral compression fractures and bone pain. Histomorphometric analysis of bone revealed increased mast cells, elevated static parameters of bone resorption, and low bone formation. Serum calcium, phosphorus, and alkaline phosphatase were normal; however, serum 1,25-dihydroxyvitamin D3 and osteocalcin levels were low. Histamine levels in plasma and urine were elevated. Following therapy with ketotifen, the patient had resolution of bone pain along with decreased flushing and pruritus. Elevated plasma and urine histamine levels normalized, as did 1,25-dihydroxyvitamin D3 and osteocalcin levels. Indices of low bone formation improved on therapy. Eroded surfaces improved but remained elevated. This case is the first demonstration that bone symptoms and histomorphometric change in systemic mastocytosis are reversed with inhibition of mast cell degranulation. The role of mast cells and their products in bone metabolism is poorly understood, but the therapy of bone disease in systemic mastocytosis should include inhibition of the release of mast cell products along with the use of histamine antagonist.  相似文献   
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