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   505篇
  免费   1篇
综合类   1篇
化学工业   1篇
机械仪表   1篇
轻工业   1篇
石油天然气   1篇
无线电   1篇
冶金工业   500篇
  2019年   1篇
  2016年   1篇
  2013年   1篇
  2003年   1篇
  2002年   2篇
  1999年   15篇
  1998年   149篇
  1997年   87篇
  1996年   76篇
  1995年   30篇
  1994年   28篇
  1993年   32篇
  1992年   4篇
  1991年   6篇
  1990年   6篇
  1989年   6篇
  1988年   8篇
  1987年   5篇
  1986年   3篇
  1985年   6篇
  1983年   1篇
  1982年   3篇
  1981年   2篇
  1980年   5篇
  1977年   12篇
  1976年   16篇
排序方式: 共有506条查询结果,搜索用时 15 毫秒
501.
502.
503.
504.
505.
Recent studies demonstrate the relationship of microvessel density to malignant progression in breast cancer (N. Weidner, J. P. Semple, W. R. Welch, and J. Folkman, N. Engl. J. Med., 324: 1-8, 1991), underscoring the importance of angiogenesis in this tumor. Crucial in tumor angiogenesis are the paracrine actions of tumor-secreted factors (e.g., vascular endothelial growth factor), which have been thought to derive from the tumor epithelial cells themselves. We demonstrate that in response to hypoxic conditions, human mammary fibroblasts dramatically up-regulate vascular endothelial growth factor mRNA and increase vascular endothelial growth factor protein levels in accordance with the degree of oxygen deprivation. Thus, mammary stromal cells, only recently considered in the regulation of breast carcinomas, may play a hitherto unrealized role in breast cancer angiogenesis.  相似文献   
506.
PURPOSE: We determined if urethral preservation and orthotopic bladder replacement in patients with transitional cell carcinoma within the prostatic urethra or prostate placed these patients at risk for urethral recurrence or death. MATERIALS AND METHODS: The clinical course of all patients undergoing urethral preservation and orthotopic bladder replacement was reviewed. The urethra was sacrificed only if the distal prostatic urethral margin was positive for transitional cell carcinoma. The pathological T stage and the grade of the primary malignancy, local recurrence, site of recurrence (urethral, pelvic, distant) and death were documented. RESULTS: Of 81 patients 70 were evaluable (June 1996) with a mean followup of 35 months. Of the 70 patients 48 were alive without evidence of disease for a mean of 38 months (range 8 to 107) and 5 died without evidence of disease. Eight of these 53 patients (15%) had prostatic involvement (carcinoma in situ in 6, intraductal carcinoma in 1 and stromal invasive transitional cell carcinoma in 1). Of the 70 patients 17 had disease recurrence (13 died of disease and 4 are alive, 1 of whom had urethral recurrence without initial prostatic transitional cell carcinoma). Of the 17 patients (35%) 6 had transitional cell carcinoma prostatic involvement (carcinoma in situ in 4 and stromal invasion in 2), and 5 of these 6 died, none with or of urethral recurrence but of the primary bladder pathology. Of these 5 patients 1 had stromal invasive transitional cell carcinoma of the prostate and experienced a bulbar urethra recurrence at 1 month and a pelvic recurrence at 3 months, and died at 5 months. Death was not secondary to the urethral recurrence. Thus, of the 14 patients who had prostatic transitional cell carcinoma, only 1 had urethral recurrence (7%), and this recurrence did not present as the cause of death. CONCLUSIONS: The guidelines for urethral resection can be relaxed, increasing the opportunities for orthotopic reconstruction, without placing the patients at increased risk for death of transitional cell carcinoma.  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