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   297篇
  免费   16篇
  国内免费   7篇
耳鼻咽喉   1篇
儿科学   29篇
妇产科学   7篇
基础医学   31篇
口腔科学   15篇
临床医学   46篇
内科学   37篇
皮肤病学   7篇
神经病学   17篇
特种医学   38篇
外科学   49篇
综合类   7篇
预防医学   11篇
药学   15篇
肿瘤学   10篇
  2023年   1篇
  2022年   1篇
  2021年   2篇
  2020年   5篇
  2019年   2篇
  2018年   7篇
  2017年   3篇
  2016年   3篇
  2015年   8篇
  2014年   9篇
  2013年   7篇
  2012年   11篇
  2011年   10篇
  2010年   17篇
  2009年   21篇
  2008年   8篇
  2007年   20篇
  2006年   31篇
  2005年   5篇
  2004年   3篇
  2003年   2篇
  2002年   12篇
  2001年   5篇
  2000年   3篇
  1999年   4篇
  1998年   16篇
  1997年   16篇
  1996年   12篇
  1995年   7篇
  1994年   14篇
  1993年   11篇
  1992年   6篇
  1991年   2篇
  1989年   1篇
  1988年   5篇
  1987年   2篇
  1986年   4篇
  1985年   7篇
  1984年   3篇
  1982年   3篇
  1981年   4篇
  1978年   2篇
  1976年   1篇
  1975年   1篇
  1969年   1篇
  1968年   2篇
排序方式: 共有320条查询结果,搜索用时 15 毫秒
61.
Toxins produced by staphylococci and enterobacteria isolated from the nasopharynx of cases of sudden infant death syndrome (SIDS) have a lethal effect when injected into chick embryos. If the toxins are progressively diluted the lethal effect disappears, but certain combinations of toxins show synergy so that if sublethal doses are mixed a highly lethal effect is produced. In this paper it is shown that nicotine at very low concentrations (less than that produced in man by 0.05 cigarettes) potentiates the lethal action of certain SIDS associated bacterial toxins and markedly potentiates the lethal action of synergistic combinations of bacterial toxins. These results could explain, at least in part, why parental smoking increases the risk of SIDS. They also provide further support for the common bacterial toxin hypothesis of cot death.  相似文献   
62.
Elevated sleep arousal thresholds in enuretic boys: clinical implications   总被引:1,自引:0,他引:1  
Enuretic children are described as difficult to arouse from sleep. We studied auditory sleep arousal thresholds in enuretic boys and report on die clinical implications of these findings. Fifteen enuretic and 18 control subjects (7–12-year-old males) were studied in a sleep laboratory for four consecutive nights using standard polysomnographic recording techniques. Sleep was undisturbed for the initial two nights and waking thresholds were measured on the following two nights. Enuretic children wet most frequently in the first two-thirds of the night. Arousal attempts were successful 39.7% of the time in controls and only 9.3% of the time in enuretics. In conclusion, enuretic males were more difficult to arouse than age-matched controls. The elevated arousal thresholds may be due to delayed maturation. Treatment programmes that rely on awakening should be aware of these features.  相似文献   
63.
Bordin  JO; Heddle  NM; Blajchman  MA 《Blood》1994,84(6):1703-1721
A considerable literature has accumulated over the past decade indicating that leukocytes present in allogeneic cellular blood components, intended for transfusion, are associated with adverse effects to the recipient. These include the development of febrile transfusion reactions, graft-versus-host disease, alloimmunization to leukocyte antigens, and the immunomodulatory effects that might influence the prognosis of patients with a malignancy. Moreover, it has become evident that such leukocytes may be the vector of infectious agents such as CMV, HTLV-I/II, and EBV as well as other viruses. An interesting development that has occurred coincidentally in transfusion medicine is that agencies responsible for the provision of blood products are being designated manufacturers of biologicals. The trend among manufacturers of biologicals is to try to produce pure products to provide for the specific therapeutic need of patients. Thus, with the realization that allogeneic leukocytes and their products may have adverse biologic activities, there is increasing pressure from various sources for the reduction of the leukocyte content in allogeneic blood components to minimize the occurrence of their adverse effects. Although the threshold leukocyte number below which these effects might no longer occur is still to be determined, a 2 to 3 log10 leukocyte reduction, provided by the currently available commercial leukocyte filters, has been shown to reduce the frequency of many of such reactions. On the other hand, the immunosuppressive effects produced by the infusion of allogeneic leukocytes might be beneficial for some patients, ie, for the maintenance of kidney allografts, in possibly reducing the relapse rate in patients with inflammatory bowel diseases, and in ameliorating recurrent spontaneous abortion. Moreover, therapeutic granulocyte transfusions may be of benefit in certain well- defined categories of patients infected with bacteria, yeast, and/or fungi. These include neonates with bacterial sepsis associated with bone marrow failure as well as severely neutropenic leukemic patients with an infection unresponsive to appropriate and specific antibiotic therapy. Many of the results obtained with the use of leukocyte depletion filters are tantalizing, but the actual clinical benefit of leukodepletion has not been established in most instances, because much of the available data are retrospective or from uncontrolled clinical trials. Moreover, issues of cost-effectiveness and quality control have not been considered adequately. Properly designed prospective clinical trials are essential to provide data with which to answer such questions and also to help define the optimal conditions required for the preparation of blood components ultimately destined for clinical use. Only with the availability of such data can sound decisions be made about the clinical value of leukodepletion.  相似文献   
64.
65.
Inthispaper ,wereportedriskfactorsassociatedwithHIVinfectionamongwomenandtheirimplicationsforAIDSpreventioneffortsintheDodomaregion ,Tanzania .1 SUBJECTSANDMETHODS1.1 Thepopulationandsampleselection ThestudywasconductedintheDodomaregion ,whichhasanestimate…  相似文献   
66.
A prospective study was undertaken to identify possible factors related to the duration of breast feeding. Two hundred and thirty-eight mothers who had delivered normal single babies with birth weights greater than 2.5 kg and had initiated breast feeding were randomly selected at the maternity hospital, Hospital de Clinicas de Porto Alegre, Brazil, and followed by mail questionnaires until termination of breast feeding, or until the end of the first year. If no reply was received, telephone contact or home visits were made. The group of mothers who stopped breast feeding prior to the end of the third month was compared with those who extended breast feeding beyond three months with respect to socioeconomic, biological, environmental, medical and psychological factors. The variables with a significant coefficient of association with early termination of breast feeding were maternal education, past experience with breast feeding, help of a maid, help with housework provided by a relative, breast feeding orientation during prenatal care and encouragement from the husband. These factors act simultaneously, with interactions among them.  相似文献   
67.
68.
69.
70.
A patient with nasopharyngeal carcinoma developed clubbing and hypertrophic osteoarthropathy 6 months before radiological detection of secondary deposits in the lung. Another patient with nasopharyngeal carcinoma developed digital clubbing and hypertrophic osteoarthropathy 6 months after the discovery of lung metastases. Development of a paraneoplastic syndrome in the form of hypertrophic osteoarthropathy and digital clubbing is very rare. This manifestation of nasopharyngeal cancers is presented, with a short review of its biology and pathogenesis.  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