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   596篇
  免费   1篇
  国内免费   2篇
电工技术   3篇
综合类   8篇
化学工业   4篇
机械仪表   1篇
建筑科学   4篇
矿业工程   1篇
轻工业   1篇
武器工业   1篇
无线电   7篇
一般工业技术   1篇
冶金工业   566篇
自动化技术   2篇
  2018年   1篇
  2014年   1篇
  2008年   1篇
  2007年   1篇
  2004年   6篇
  2003年   3篇
  2002年   6篇
  2001年   4篇
  2000年   3篇
  1999年   20篇
  1998年   173篇
  1997年   72篇
  1996年   54篇
  1995年   39篇
  1994年   27篇
  1993年   36篇
  1992年   3篇
  1991年   7篇
  1990年   6篇
  1989年   8篇
  1988年   10篇
  1987年   15篇
  1986年   10篇
  1985年   7篇
  1983年   3篇
  1982年   3篇
  1981年   3篇
  1980年   5篇
  1979年   1篇
  1978年   2篇
  1977年   24篇
  1976年   41篇
  1975年   1篇
  1955年   3篇
排序方式: 共有599条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
45.
Four rhesus monkeys were reared for the first eight months of life in total social isolation. One animal died during this period; the three remaining subjects were treated with diazepam in an isolation chamber, in their home cages, and in a playroom testing situation. Diazepam significantly decreased the self-disturbance behaviors of two subjects, and there was even the appearance of some social behaviors, although they were limited and not of the same quality as in nonisolated subjects. The authors discuss the implications of the data for understanding the significance of the social isolation syndrome in monkeys as a model for human psychoses.  相似文献   
46.
The records of 628 patients admitted to the Joint Study of Extracranial Arterial Occlusion with transient symptoms of carotid system ischemic disease were examined to determine the accuracy of predicting disease of the extracranial internal carotid artery on the basis of clinical information alone. A patient with a history of episodes of amaurosis fugax is more likely to have a lesion of the internal carotid artery on the same side than if he were having only transient cerebral ischemic attacks. In patients with transient symptoms and a carotid bruit on the appropriate side, the incidence of an angiographically normal carotid artery was 15%. In those patients with transient symptoms and no palpable pulsation in the cervical region on the appropirate side, the incidence of an angiographically normal carotid artery was zero.  相似文献   
47.
The present report describes an infant with severe combined immunodeficiency and cartilage-hair hypoplasia whose lymphocytes responded to thymosin in vitro. Immunologic evaluation was undertaken at 4 1/2 months of age following a history of recurrent severe infection. Family history included three cousins who died in early infancy, one from streptococcal meningitis and pneumonia, one from generalized varicella, and another from reticuloendotheliosis. Quantitative immunoglobulins were markedly depressed: IgG 141, IgA 0, and IgM 24 mg/100 ml. There was an absolute lymphopenia, multiple skin tests were negative, and in vitro lymphocyte responses to mitogens and antigens were depressed. Spontaneous E rosette determinations were 21% compared with control values of 65.7%. Erythrocyte adenosine deaminase (ADA) activity was normal. The patient's E rosette formation increased in the presence of thymosin, fraction 5, reaching a maximum of 56% with a concentration of 500 mug thymosin. Blastogenic responses to phytohemagglutinin also increased in the presence of thymosin. Transplantation of 24-week fetal thymus in Millipore diffusion chambers and subsequently transplantation of 18-week fetal thymus by intraperitoneal injection was accomplished. E rosettes increased to 35-40% and blastogenic responses to mitogens increased. Eight days after the second transplant the patient underwent a mild graft vs. host reaction which subsided after 1 week and mitogen blastogenic responses again increased to 5-8 times previous values, but still well below control ranges. Repeated episodes of pulmonary infection ensued, cor pulmonale resulted, and the clinical course was relentlessly downhill with the patient expiring from respiratory failure 5 months after transplantation.  相似文献   
48.
Glomerular diseases are associated with changes in glomerular membrane permeability properties that alter filtration rate of plasma water and barrier function of the capillary wall. To estimate intrinsic permeability properties that regulate transmembrane transport of water and macromolecules, theoretical analysis of renal clearance of tracer molecules can be used. The development of adequate theoretical models is required to achieve sufficient accuracy to simulate complicated biological processes. Current research in this area is aimed at improving and validating the presently available models in order to characterize the nature of permeability changes associated with pathological conditions. This is a key step in understanding the pathophysiological nature of glomerular diseases and in the development of effective treatments.  相似文献   
49.
Heartworm infected small animal patients are seldom seen in the Netherlands, because the parasite's life cycle cannot be completed in this climate. We report here four cases of the disease in dogs brought to the Netherlands from endemic heartworm areas. The initial diagnosis was based upon this knowledge and clinical signs (low exercise tolerance and coughing). The diagnosis was confirmed by the radiographic finding of variable pulmonary artery enlargement, the electrocardiographic finding of right ventricular hyperptrophy and the presence of microfilariae in the peripheral blood. Treatment resulted in recovery in three of these patients but the fourth died soon after initiation of the therapy.  相似文献   
50.
IgA class reticulin antibodies were not found in patients with Crohn's disease, ulcerative colitis, and hiatus hernia despite a significant incidence of IgG class reticulin antibodies. None of 56 normal healthy subjects was positive. In contrast, 13 (76%) of the sera from 17 patients with coeliac disease on normal diet were positive for IgA class antibodies as were 19 (20%) of 93 first degree relatives. Seventy-three relatives underwent jejunal biopsy. Grade III (flat) histology was found in 13 and, of these patients, 10 (77%) showed IgA class reticulin antibody in their serum. It is suggested that determination of IgA class reticulin antibodies was a useful test to determine which relative must be biopsied.  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