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   971篇
  免费   1篇
化学工业   1篇
机械仪表   1篇
能源动力   1篇
一般工业技术   4篇
冶金工业   961篇
自动化技术   4篇
  2022年   1篇
  2019年   1篇
  2017年   1篇
  2016年   2篇
  2014年   1篇
  2006年   2篇
  2005年   1篇
  2004年   1篇
  2003年   2篇
  2002年   1篇
  1999年   21篇
  1998年   284篇
  1997年   168篇
  1996年   106篇
  1995年   53篇
  1994年   62篇
  1993年   57篇
  1992年   5篇
  1991年   7篇
  1990年   14篇
  1989年   10篇
  1988年   10篇
  1987年   7篇
  1986年   1篇
  1985年   6篇
  1983年   2篇
  1982年   5篇
  1981年   6篇
  1980年   10篇
  1978年   5篇
  1977年   35篇
  1976年   81篇
  1975年   2篇
  1955年   2篇
排序方式: 共有972条查询结果,搜索用时 15 毫秒
51.
52.
53.
The deregulation of cyclin D1 (BCL-1, PRAD1, CCND1) protein, normally synthesized in the G1 phase of the cell cycle, has been implicated in the pathogenesis of some malignant neoplasms, including invasive mammary carcinomas. We used rabbit polyclonal antibody 19 to detect cyclin D1 in 55 infiltrating ductal carcinomas and compared the findings to six important clinicopathologic parameters and cyclin D1 gene amplification. Nuclear immunoreactivity of variable intensity for cyclin D1 was present in 35% of the neoplasms, whereas immunoreactivity of normal mammary epithelial nuclei was absent. No significant correlations were observed between immunoreactivity and patient age, axillary lymph node status, estrogen receptors, progesterone receptors, histologic grade, or any of its three components. There was a correlation between cyclin D1 immunostaining and tumor size (P = 0.013). Fourteen of 15 tumors 2 cm or less were negative, whereas 7 of 12 neoplasms larger than 4 cm were immunopositive. Fifteen percent of the invasive carcinomas had cyclin D1 gene amplification. Of these eight tumors, six showed cyclin D1 immunoreactivity (P = 0.017). In this study, cyclin D1 was detected immunohistochemically in approximately one-third of infiltrating ductal carcinomas; approximately one-third of these had detectable cyclin D1 gene amplification. These results further implicate cyclin D1 in breast tumorigenesis and are additional evidence for the role of cell cycle regulatory proteins in invasive mammary carcinoma.  相似文献   
54.
55.
56.
Previous results, using a passive transfer assay, have shown that recrudescences of Plasmodium chabaudi chabaudi AS strain are antigenically different from the infecting parental population and also that the recrudescence appears to be a mix of antigenic types. This present study examines further these recrudescent populations using an indirect fluorescent antibody test on live, schizont-infected red blood cells. This analysis shows that ten clones derived from a recrudescence are all antigenically different from the parent population and that some are different from each other. The use of this method to examine the antigenic types of recrudescent clones after transmission through mosquitoes also demonstrates a resulting change in antigenicity. Such results showing a link between mosquito transmission and varying antigenicity may have important implications in terms of immunity and vaccine development.  相似文献   
57.
Despite the fact that the neuroleptic drugs have been widely used for more than 40 years, one of their most common side-effects, akathisia, has been relatively neglected. There are still no universally agreed diagnostic criteria for akathisia, particularly chronic akathisia, and in this review article, we discuss the controversies surrounding the voluntary nature of its motor features and the importance of the dysphoric component. We also review the published epidemiological studies to show the great variation in frequency of occurrence. Finally, we discuss the possible neurotransmitters involved in the pathophysiology and treatment of this condition.  相似文献   
58.
59.
60.
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