全文获取类型
收费全文 | 812篇 |
免费 | 0篇 |
国内免费 | 2篇 |
专业分类
综合类 | 2篇 |
化学工业 | 9篇 |
金属工艺 | 4篇 |
无线电 | 1篇 |
一般工业技术 | 1篇 |
冶金工业 | 793篇 |
原子能技术 | 2篇 |
自动化技术 | 2篇 |
出版年
2012年 | 1篇 |
2010年 | 1篇 |
2007年 | 1篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 6篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 22篇 |
1998年 | 266篇 |
1997年 | 157篇 |
1996年 | 86篇 |
1995年 | 46篇 |
1994年 | 35篇 |
1993年 | 50篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 8篇 |
1988年 | 5篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1978年 | 1篇 |
1977年 | 30篇 |
1976年 | 54篇 |
排序方式: 共有814条查询结果,搜索用时 906 毫秒
111.
This study was designed to determine what effect physical training has on heart rate and stroke volume responses to exercise stress and to determine if exercise altered the distribution of uterine blood flow. Measurements were made in ten pregnant ewes at rest and immediately following exercise on a treadmill. Five ewes underwent physical training for 3 wk prior to measurement. An increase in heart rate with no change in stroke volume was observed following exercise in both trained and untrained ewes. Total uterine blood flow was not changed following exercise, but distribution was altered in favor of the placenta. Blood flow was evenly distributed within the placenta before and after exercise. The redistribution of flow to the placenta that occurs after exercise. tphe redistribution of flow to the placenta that occurs after exercise might represent a compensatory mechanism for the fetus. 相似文献
112.
LB Simper 《Canadian Metallurgical Quarterly》1976,138(29):1757-1758
113.
114.
Cells of nasal placode of chick embryos were studied with thymidine H3 and autoradiography. Our results shown, that the nuclei in the nasal placode synthesize DNA in the outer zone, then migrate toward the inner zone to undergo division and subsequently return to the outer zone. 相似文献
115.
116.
117.
LB Burkert VS Sharma AV Pisciotta HM Ranney S Bruckheimer 《Canadian Metallurgical Quarterly》1976,48(5):645-651
A severe hemolytic crisis was observed in a 34-yr-old female of English-Irish extraction following a viral illness treated with acetaminophen. Heinz bodies and heat instability were present only during a transient hemolytic event. A challenge dose of acetaminophen caused no detectable hematologic abnormality. Structural studies of the hemoglobin during hemolysis and again after complete recovery localized the abnormality to tryptic peptide beta Tp-5, and automated sequencing of I 125-labeled beta chains indicated a replacement of phenylalanine (C7) beta 41 by tyrosine. Substitution of the next residue, phenylalanine (CD1) beta 42 by serine (Hb Hammersmith), has resulted in chronic severe Heinz body hemolytic anemia. The lack of chronic anemia in the present disorder may reflect the different relationships of beta41 and beta 42 and/or the similarities in volume and hydrophobicity of tyrosine and phenylalanine. It is suggested that substitution of tyrosine for phenylalanine in Hb Mequon may disturb the critical environment around the heme group and render it susceptible to oxidative denaturation in the presence of infections and/or drugs. 相似文献
118.
119.
120.