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   1491篇
  免费   0篇
化学工业   4篇
轻工业   3篇
一般工业技术   3篇
冶金工业   1481篇
  2015年   1篇
  2013年   2篇
  2012年   1篇
  2010年   1篇
  2006年   1篇
  2003年   4篇
  2000年   1篇
  1999年   35篇
  1998年   468篇
  1997年   277篇
  1996年   179篇
  1995年   91篇
  1994年   72篇
  1993年   84篇
  1992年   7篇
  1991年   23篇
  1990年   18篇
  1989年   17篇
  1988年   16篇
  1987年   26篇
  1986年   16篇
  1985年   13篇
  1982年   7篇
  1981年   14篇
  1980年   11篇
  1979年   2篇
  1978年   3篇
  1977年   24篇
  1976年   75篇
  1975年   1篇
  1955年   1篇
排序方式: 共有1491条查询结果,搜索用时 0 毫秒
101.
102.
103.
104.
105.
106.
A prospective vascular audit was performed in this hospital between 1988 and 1994. There was a substantial increase in the number of vascular reconstructions (78 in 1988; 141 in 1994). Aortobifemoral grafts for occlusive disease comprised 18 per cent of the operations in 1988 and 0.7 per cent in 1994 (95 per cent confidence interval 0.086-0.259). There was a corresponding increase in the number of extra-anatomic grafts (from 3 to 20.6 per cent). There was a threefold increase in the number of percutaneous angioplasties performed for iliac occlusive lesions (14 in 1988; 41 plus 13 iliac stent procedures in 1994). This had no impact on the total rate of surgical intervention for aortoiliac disease, although it probably aided the shift to extra-anatomic reconstruction by dilatation of the donor side. To investigate whether this change is national, rather than local, graft sales figures were obtained from two vascular graft companies; these confirmed a national trend away from aortobifemoral grafting and provide some evidence to support an increase in extra-anatomic bypass grafting.  相似文献   
107.
Changes in complete blood count (CBC), bone marrow, reticulocyte count, coagulation profile, biochemical analysis, and serum iron, transferrin, and immunoglobulin M (IgM) concentrations were measured three and 10 days after splenectomy in 12 dogs. Spleens were cultured aerobically for bacteria and submitted for histopathological evaluation in 23 dogs undergoing splenectomy. There were no consistent changes in red blood cell (RBC), white blood cell (WBC), or platelet counts; bone-marrow samples; or biochemical profiles. Serum iron, transferrin, and IgM concentrations remained normal. Eight (35%) bacterial cultures yielded growth. Five of the 23 dogs had pyrexic episodes two-to-five days after surgery. In contrast to previous reports done on healthy dogs, this study shows that dogs with splenic disease have no characteristic changes in hematological or biochemical parameters after splenectomy. Rather, the changes tended to reflect the primary disease process. Splenic vascular compromise or a decrease in processing of bacteria may have resulted in the bacterial growth. There was no direct correlation to pyrexic postoperative episodes.  相似文献   
108.
109.
Direct ethanolic and sequential petroleum ether, chloroform, acetone and ethanolic extracts (50-100 mg/kg, i.p.) of P. pinnata seeds given 30-60 min before revealed anti-inflammatory, analgesic and anti-ulcerogenic activities in rats. The activities were present maximum in petroleum ether and chloroform extracts. However, the extracts also showed shortening of pentobarbitone induced 'sleep time' in rats.  相似文献   
110.
A memory-based processing approach to discourse comprehension emphasizes the rapid deployment of information in memory to facilitate understanding of the text that is currently being read. S. B. Greene, R. J. Gerrig, G. McKoon, and R. Ratcliff (1994) demonstrated that when a text described the reunion of 2 characters who had previously discussed a 3rd character, the accessibility of the 3rd character increased, and the use of an unheralded pronoun (R. J. Gerrig, 1986) to refer to that character was felicitous. In experiments in this article, the authors demonstrate that concepts related to the unheralded pronoun also increase in accessibility and that those concepts form associations in memory with concepts present in the discourse at the time the pronoun is used. The authors also show that the increase in accessibility for the referent of the pronoun, as well as the appropriate long-term memory associations, occurs even in the absence of the pronoun.  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