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   234篇
  免费   8篇
  国内免费   36篇
耳鼻咽喉   1篇
儿科学   8篇
妇产科学   4篇
基础医学   11篇
口腔科学   7篇
临床医学   38篇
内科学   70篇
皮肤病学   6篇
神经病学   5篇
特种医学   64篇
外科学   15篇
综合类   16篇
预防医学   7篇
眼科学   1篇
药学   17篇
肿瘤学   8篇
  2020年   1篇
  2018年   2篇
  2017年   2篇
  2016年   4篇
  2014年   6篇
  2013年   4篇
  2012年   4篇
  2011年   5篇
  2010年   13篇
  2009年   13篇
  2008年   6篇
  2007年   28篇
  2006年   2篇
  2005年   7篇
  2004年   6篇
  2003年   4篇
  2002年   4篇
  2001年   7篇
  2000年   3篇
  1999年   2篇
  1998年   18篇
  1997年   13篇
  1996年   17篇
  1995年   8篇
  1994年   14篇
  1993年   19篇
  1992年   1篇
  1991年   3篇
  1990年   5篇
  1989年   9篇
  1988年   7篇
  1987年   2篇
  1986年   4篇
  1985年   8篇
  1984年   4篇
  1983年   1篇
  1982年   1篇
  1981年   6篇
  1980年   11篇
  1976年   2篇
  1975年   1篇
  1968年   1篇
排序方式: 共有278条查询结果,搜索用时 15 毫秒
11.
12.
We have studied the role of different conditioning regimens for engraftment of genetically marked hematopoietic repopulating cells in dogs. Peripheral blood (PB) and/or marrow cells collected after treatment with recombinant canine stem cell factor (rcSCF) or cyclophosphamide were transduced in a vector-containing long-term culture system. Three different vector-producing cell lines with similar viral titers were used. In two of them, the neo-containing LN vector was packaged either in the PA317 cell line with an amphotropic murine retrovirus envelope or the PG13 cell line with the gibbon ape leukemia virus (GALV) envelope. The MFG/GC vector produced in PA317 cells contained the human glucocerebrosidase gene. Nineteen dogs received either no conditioning (group A, n = 5), irradiation to both humeri with 1,000 cGy (group B, n = 5), a sublethal dose of cyclophosphamide 40 mg/kg (group C, n = 4), a sublethal dose of 200 or 300 cGy total body irradiation (TBI) (group D, n = 3), or an otherwise lethal dose of 920 cGy TBI (group E, n = 3) before intravenous (groups A, C, D, E) or intramedullary (group B) infusion of the transduced autologous hematopoietic cells. Transduction efficiency of hematopoietic cells at the time of infusion into the animals was similar among the different conditioning groups. Dogs were observed for at least 6 months. PB granulocytes were obtained at least every 3 weeks after transplant and analyzed by polymerase chain reaction for the presence of the transduced genes. The percentages of positive results in dogs more than 4 weeks after transplantation were 0% without conditioning, 5% with local irradiation, 18% with sublethal cyclophosphamide, 33% with sublethal TBI, and 17% with otherwise lethal TBI. Analyzing the influence of conditioning regimens by a generalized estimating equation (GEE) technique, which considered the use of different retrovirus vectors and the number of mononuclear cells infused as potential confounding variables, we found that engraftment of genetically marked repopulating cells was significantly improved (P < .001) in dogs receiving systemic conditioning with either otherwise lethal TBI, sublethal TBI, or sublethal cyclophosphamide compared to dogs with local irradiation only or no conditioning. Within the limitation of the experimental design, these data suggest that myeloablative or myelosuppressive conditioning improves engraftment of genetically marked hematopoietic repopulating cells.  相似文献   
13.
14.
Elimination of neoplastic B cell populations from autologous bone marrow grafts also removes normal B lymphocytes. This is potentially hazardous for the reconstitution of the immune system in patients undergoing high-dose chemotherapy and total body irradiation followed by autologous marrow rescue. Five pediatric patients with B cell non- Hodgkin's lymphoma in first remission undergoing such a regimen were studied. They received bone marrow pretreated with anti-Y 29/55 monoclonal antibody and complement. B and T lymphocyte subpopulations reached normal levels within 6 months after autologous bone marrow transplantation (ABMT), and serum immunoglobulin levels became normal within 4 to 9 months. Vaccination with diphtheria and tetanus toxoid, trivalent poliomyelitis vaccine of the Salk type, and pneumococcal capsular antigens (38 to 54 months after transplantation) gave rise to specific antibody production. ABO isoagglutinins could be demonstrated in all patients. The response pattern was similar to that of patients who received unmanipulated autologous bone marrow. It is concluded that ex vivo anti-Y 29/55 depletion of the marrow graft does not induce relevant disturbances of humoral immune functions.  相似文献   
15.
Recent reports indicate an increasing prevalence of overweight among Filipino children. Considering the known association of physical activity (PA) with obesity, this study reports the findings of an objective monitoring of PA in a sample of Filipino children. The study also explores the relationship of PA with fundamental movement skills (FMS) proficiency. Thirty‐two children (6.54 ± 2.45 years old) wore an accelerometer for 7 days of PA monitoring and were assessed on five FMS (throw, catch, kick, run, jump). The children met the World Health Organization's recommendation of 60 min of PA per day, with more active time being accrued during weekdays than weekends. Children with greater FMS proficiency were found to spend more time in PA than those who were less skillful during weekends. Further research is recommended to examine PA and FMS proficiency associations, exploring the role of social interactions on weekends and weekdays.  相似文献   
16.
Gene conversion is a likely cause of mutation in PKD1   总被引:3,自引:0,他引:3  
Approximately 70% of the gene responsible for the most common form of autosomal dominant polycystic kidney disease ( PKD1 ) is replicated in several highly homologous copies located more proximally on chromosome 16. We recently have described a novel technique for mutation detection in the duplicated region of PKD1 that circumvents the difficulties posed by these homologs. We have used this method to identify two patients with a nearly identical cluster of base pair substitutions in exon 23. Since pseudogenes are known to be reservoirs for mutation via gene conversion events for a number of other diseases, we decided to test whether these sequence differences in PKD1 could have arisen as a result of this mechanism. Using changes in restriction digest patterns, we were able to show that these sequence substitutions are also present in N23HA, a rodent-human somatic cell hybrid that contains only the PKD1 homologs. Moreover, these changes were also detected in total DNA from several affected and unaffected individuals that did not harbor this mutation in their PKD1 gene copy. This is the first example of gene conversion in PKD1 , and our findings highlight the importance of using gene-specific reagents in defining PKD1 mutations.   相似文献   
17.
替硝唑软膏的研制与临床应用   总被引:9,自引:0,他引:9  
目的:研究替硝唑软膏,并应用于临床。方法:参照同类制剂,确定最优组方和制备方法,采用紫外分光光度法测定含量,用比较法进行临床疗效观察。结果:制剂制备简单,含量测定方法简便,结果可靠,经临床应用牙周炎、牙龈炎患者62例,总有效率95.3%。结论:本品是治疗牙周炎、牙龈炎的理想制剂,值得推广应用。  相似文献   
18.

Background  

Children in urban public housing are at high risk for asthma, given elevated environmental and social exposures and suboptimal medical care. For a multifactorial disease like asthma, design of intervention studies can be influenced by the relative prevalence of key risk factors. To better understand risk factors for asthma morbidity in the context of an environmental intervention study, we conducted a detailed baseline evaluation of 78 children (aged 4–17 years) from three public housing developments in Boston.  相似文献   
19.
Depressive symptoms were measured in a cohort of community-based adolescents (n = 163) at two time-points, with 1 year intervening. At Time 2, participants also answered a scale about past-year stressful life events. Depressive symptoms increased from Time 1 to Time 2, the effect being stronger for girls than for boys. Depressive symptoms were significantly correlated with concurrent measures of recent stressful life events, but this relationship disappeared after controlling for previous depressive symptoms. Rather, previous level of depressive symptoms predicted stressful life events. This demonstrates that a unidirectional model of stressful life events as the cause of depressive symptoms in adolescents is too simplistic.  相似文献   
20.
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