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   319篇
  免费   0篇
化学工业   7篇
冶金工业   312篇
  2013年   1篇
  2011年   1篇
  2010年   1篇
  2008年   1篇
  2007年   1篇
  2000年   1篇
  1999年   1篇
  1998年   80篇
  1997年   62篇
  1996年   31篇
  1995年   27篇
  1994年   20篇
  1993年   17篇
  1992年   2篇
  1991年   5篇
  1990年   6篇
  1989年   4篇
  1988年   2篇
  1987年   4篇
  1986年   2篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1982年   4篇
  1981年   2篇
  1980年   5篇
  1978年   1篇
  1977年   9篇
  1976年   23篇
  1975年   1篇
排序方式: 共有319条查询结果,搜索用时 31 毫秒
31.
BACKGROUND: Heart transplantation (HT) as a therapeutic option for end-stage chronic Chagas' heart disease (CCHD) is controversial. Reactivation of Trypanosoma cruzi infection and recurrence of the disease in the allograft are likely to occur. Furthermore, active myocarditis has been reported to predispose patients to an increased incidence and severity of rejection. METHODS AND RESULTS: We prospectively investigated the long-term follow-up of 10 patients with CCHD who underwent HT. Immunosuppression was based on cyclosporine A and azathioprine. T cruzi reactivation was prevented with benzonidazole. Besides allograft rejection surveillance, T cruzi infection was monitored through blood tests, myocardial biopsies, and serological tests. Over a mean follow-up period of 34 +/- 38 months (range, 73 to 124 months), 7 patients are alive and in NYHA functional class I. Life expectancy was 78% for the second year and 65% for 10 years. Rejection was less frequent in chagasic than in age- and sex-matched control patients (mean +/- SD, 1.60 +/- 1.26 versus 5.70 +/- 1.89 episodes per patient, respectively; P = .0001); decreased severity of rejection was also observed (P = .006). T cruzi parasitemias detected on three occasions were successfully treated with benzonidazole. There were no signs of recurrence of the disease in the allograft. CONCLUSIONS: These results suggest an important role of HT in the treatment of CCHD. There was a low frequency of T cruzi infection reactivation and no signs of recurrence of the disease in the allograft. The surprisingly decreased rejection incidence and severity require further studies for elucidation.  相似文献   
32.
Canine juvenile-onset insulin-dependent diabetes mellitus is a rare disease. While pancreatic acinar atrophy is a well known picture in the dog, the simultaneous occurrence with an endocrine insufficiency has never been clearly established. The clinical, pathological and immunohistochemical findings of a three-month-old German shepherd dog with insulin-dependent diabetes mellitus concurrent with exocrine pancreatic insufficiency are described.  相似文献   
33.
34.
35.
BACKGROUND: The fact that few doctors have their own GP may help explain doctors' poor health outcomes. Barriers to the doctor as patient role may arise from problematic perceptions of the 'doctor' subject position and from its subjugation of 'other-than-doctor' positions. Medical culture appears to foster and construct inappropriate health seeking behaviour of doctors. OBJECTIVE: A behaviour model is proposed--delusion, denial and delay; self-investigation, self-diagnosis, self-treatment and self-referral. Application of a behaviour change model could facilitate the doctor as patient role. DISCUSSION: Literary theory and sociology critiques may help peel off the social construction of 'doctor'. The realisation of such myths may allow access to medical care enjoyed by the general community.  相似文献   
36.
37.
A study was made of the influence of psycho-emotional strain, experienced by students when taking examinations, on the erythrocyte electrophoretic mobility (EPM). It has been shown that students under psycho-emotional strain the mean value of EPM remains the same, but changes were observed in the form of EPM distribution, while estimated by asymmetry and excession coefficients. Similar results were obtained when adrenalin was added to the blood.  相似文献   
38.
Murine peritoneal macrophages, activated by BCG vaccine, and human peripheral blood monocytes, activated by lipopolysaccharides, exerted neurite stimulating or neurite inhibiting effects in various periods of activation. The supernatants of these preparations were active in organotypic culture of chick embryo dorsal root ganglia. The inhibition of neurite growth on the 1st day of cultivation was followed by the neurite-stimulating effect. The fluctuation of neurite-inhibition and neurite-stimulation effect of macrophage supernatants suggest the availability of certain changes in cytokine composition in different periods of macrophage activation.  相似文献   
39.
As a preliminary step in an analysis of Hox gene expression and radial body plan specification in sea urchin development, we amplified partial homeobox sequences in H. purpurescens by PCR using degenerate primers. The primers, HoxE and HoxF (Pendleton et al., 1993), spanned a highly conserved region of 82 nucleotides encompassing amino acids 21-47 of the homeodomain. Seven Hox-type homeobox sequences and two non-Hox homeobox sequences were identified. The seven Hox-type sequences were placed provisionally in Hox paralogous groups, one in paralogous group 3, three in paralogous groups 6-8 and three in paralogous groups 9 13. The non-Hox sequences had similarities with Xlox and Gbx homeobox genes.  相似文献   
40.
Rat aortic lysyl oxidase cDNA was expressed under a metallothionein promoter in Chinese hamster ovary cells using a dihydrofolate reductase selection marker. One methotrexate-resistant cell line, LOD-06, generated by transfecting with full-length cDNA, yielded lysyl oxidase proteins consistent with the 50 kDa proenzyme and a 29 kDa mature catalyst. A second cell line, LOD32-2, was generated by transfection with a truncated cDNA lacking sequences which code for the bulk of the propeptide region. Both cell lines secreted apparently identical, 29 kDa forms of mature lysyl oxidase each of which catalyzed the deamination of human recombinant tropoelastin and alkylamines, consistent with the known specificity of lysyl oxidase. The secreted enzyme forms were inhibited by chemical inhibitors of lysyl oxidase activity, including beta-aminopropionitrile, phenylhydrazine, ethylenediamine, alpha, alpha'-dipyridyl, and diethyldithiocarbamate. Sensitivity to these agents is consistent with the presence of copper and carbonyl cofactors in the expressed enzymes, characteristic of lysyl oxidase from connective tissues. These results indicate the lack of essentiality of the deleted proprotein sequence for the proper folding, generation of catalytic function, and secretion of lysyl oxidase.  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