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   1244篇
  免费   1篇
化学工业   6篇
机械仪表   1篇
能源动力   3篇
轻工业   4篇
石油天然气   1篇
无线电   3篇
一般工业技术   3篇
冶金工业   1217篇
原子能技术   1篇
自动化技术   6篇
  2019年   2篇
  2018年   1篇
  2012年   1篇
  2011年   3篇
  2009年   2篇
  2008年   1篇
  2006年   3篇
  2005年   1篇
  2004年   1篇
  2003年   2篇
  2000年   2篇
  1999年   38篇
  1998年   371篇
  1997年   237篇
  1996年   134篇
  1995年   86篇
  1994年   55篇
  1993年   71篇
  1992年   8篇
  1991年   20篇
  1990年   15篇
  1989年   15篇
  1988年   11篇
  1987年   22篇
  1986年   18篇
  1985年   24篇
  1984年   1篇
  1983年   5篇
  1982年   2篇
  1981年   4篇
  1980年   9篇
  1979年   1篇
  1978年   4篇
  1977年   25篇
  1976年   45篇
  1975年   3篇
  1965年   1篇
  1955年   1篇
排序方式: 共有1245条查询结果,搜索用时 0 毫秒
51.
52.
53.
54.
Intracerebral infection of mice aged 2-3 days with hepatitis C virus (HCV) from chronically infected suckling mouse brain cultures and porcine embryo cells resulted in the death of animals after 12-14 days. Repeated passages of HCV in animals decreased the incubation period to just 3-4 days. Blood serum of surviving mice collected during the 4th week postinfection contained antiHCV antibodies detected by enzyme immunoassay and hemagglutination inhibition test. The results are proof of creation of a new in vivo model of experimental HCV infection.  相似文献   
55.
IQs of rapists were compared to IQs of nonrapist prisoners convicted of violent crimes and nonrapist prisoners convicted of nonviolent crimes. Subjects were 136 male convicted felons in the Kentucky State Penitentiary. Determination of violent vs. nonviolent crimes other than rape was made upon consultation with a Kentucky Commonwealth Attorney. The results revealed significantly lower IQs for rapists compared to nonrapists convicted of violent crimes and compared to heterogeneous nonrapist convicts. The present research supports the findings of Karacan and co-workers, indicating a general tendency for rapists to have lower IQs than other convicted prisoners.  相似文献   
56.
Three experiments examined the influence of videotaped classroom events on the academic performance and study behavior of reading-disabled and normally reading children in grades 1 through 6. In experiments 1 and 2a an experimenter-controlled presentation of these distractors resulted in performance decrements, the magnitude of which was greater for higher difficulty tasks. The distractor effects were similar for the two groups in this condition. However, when the children themselves were allowed to control their degree of exposure to the same distractors in experiment 2b, the reading-disabled children were less likely to act to escape the distraction. Results are discussed in terms of children's metacognitive awareness of distraction, and implications for the classroom are considered.  相似文献   
57.
58.
The results of PUVA treatment for severe alopecia areata (AA) were reviewed in 102 patients. Fifty-three per cent had greater than 90% regrowth of hair. Although these results appear to be encouraging, they differ little from what would be expected with no treatment. We consider that PUVA is not an effective treatment for AA.  相似文献   
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