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   34篇
  免费   0篇
化学   21篇
晶体学   1篇
力学   1篇
数学   1篇
物理学   10篇
  2023年   1篇
  2013年   1篇
  2012年   1篇
  2010年   1篇
  2009年   1篇
  2006年   1篇
  2002年   2篇
  2001年   1篇
  2000年   1篇
  1999年   3篇
  1997年   1篇
  1992年   1篇
  1991年   1篇
  1990年   2篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1977年   1篇
  1976年   2篇
  1975年   1篇
  1974年   5篇
  1973年   1篇
  1967年   1篇
排序方式: 共有34条查询结果,搜索用时 15 毫秒
1.
A series of 1-aminoalkyl-pyrrolo[2,3-c]azepin-8-one derivatives was synthesized and evaluated as alpha 1 adrenergic and serotonin 2 (5-HT2) receptor antagonists, with the aim of finding a novel antihypertensive agent potently exhibiting both activities. Some compounds with a 4-[4-(4-fluorobenzoyl)piperidino]butyl group at the 1-position exhibited both activities, and varied significantly in terms of the substituents at the 4-position of the pyrroloazepine ring. Among the compounds obtained in this study, (E)-1-[4-[4-(4-fluorobenzoyl)piperidino]-butyl]-4-hydroxyimino-7- methyl-1,4,5,6,7,8-hexahydropyrrolo[2,3-c]azepin-8-one (15a, SUN9221) displayed potent alpha 1-adrenergic antagonistic activity (pA2 = 8.89 +/- 0.21) and 5-HT2 antagonistic activity (pA2 = 8.74 +/- 0.22) in isolated guinea pig arteries. This compound exhibited antihypertensive activity and a duration of action equivalent to orally administered prazosin or doxazosin, 3 mg/kg, in conscious spontaneously hypertensive rats, as well as potent antiplatelet aggregation activity.  相似文献   
2.
A new series of 4-(1,4-benzoquinon-2-yl)-4-phenylbutanamides (2) were synthesized for evaluation of their pharmacological activities. All these compounds synthesized showed significant antilipidperoxidation (ALP) activities with brain homogenate in rats and some of them possessed a protective effect against hypobaric hypoxia in mice. Especially, a thiomorpholine derivative (2l, SUN-4757) showed a wide efficacy spectrum to a variety of experimental screening assays designed for cerebral protective agents, and it had a high LD50 value.  相似文献   
3.
We discuss the notion of spin squeezing considering two mutually exclusive classes of spin-s states, namely, oriented and non-oriented states. Our analysis shows that the oriented states are not squeezed while non-oriented states exhibit squeezing. We also present a new scheme for construction of spin-s states using 2s spinors oriented along different axes. Taking the case of s=1, we show that the ‘non-oriented’ nature and hence squeezing arise from the intrinsic quantum correlations that exist among the spinors in the coupled state.  相似文献   
4.
5.
β-FeSi2 bulk crystals were grown by a molten salt method with Cu or Co addition. The effect of the Cu or Co addition on the structural, electrical and thermoelectric properties was investigated. A p-type semiconducting β-FeSi2 crystal was obtained without any impurity addition. On the other hand, n-type β-FeSi2 crystals were obtained by Co doping with 1.5–4 mol% addition. For the Cu addition, β-FeSi2 crystals with large diameter columnar domains were obtained, and an increased β-phase formation was observed. In addition, a slight decrease in the carrier density and a slight increase in the Hall mobility were observed, probably due to the elimination of crystalline defects. The structural and electrical modifications of the β-FeSi2 crystals by the impurity addition is discussed.  相似文献   
6.
MK Mahanta  KS Goswami 《Pramana》2001,56(4):579-584
The aim of this brief report is to study the behaviour of sheath structure in a multi-component plasma with dust-neutral collisions. The plasma consists of electrons, ions, micron size negatively charged dust particles and neutrals. The sheath-edge potential and sheath width are calculated for collisionally dominated sheath. Comparison of collisionless and collisionally dominated sheath are made.  相似文献   
7.
8.
As an extension of our previous investigation, a series of 7-aminoalkylpyrrolo[2,3-c]azepine derivatives was synthesized and evaluated as alpha1-adrenergic- and serotonin 2 (5-HT2)-receptor antagonists, with the aim of finding a novel potent antihypertensive agent with both activities. Among the compounds obtained in this study, (E)-1-ethyl-7-[3-[4-(4-fluorophenyl)piperazin-1-yl]propyl]-4-hy droxyimino-1,4,5,6,7,8-hexahydropyrrolo[2,3-c]azepin-8-on e (16d) displayed potent alpha1-adrenoceptor blocking activity (pA2=7.83+/-0.20) and 5-HT2-receptor blocking activity (pA2=9.47+/-0.17) in isolated guinea pig arteries. At 3 mg/kg oral administration, compound 16d exhibited antihypertensive activity more potent than that of doxazosin in deoxycorticosterone acetate (DOCA)-salt hypertensive dogs. Furthermore, this compound reduced the rate of mouse acute pulmonary thromboembolytic death induced by collagen and serotonin at oral doses of 0.3 mg/kg or more, and its effect lasted for at least 6 h at 3 mg/kg.  相似文献   
9.
The effect of atmospheric water vapor on the kinetic rate behavior of the thermal decomposition of copper(II) carbonate hydroxide, Cu2CO3(OH)2, was investigated by means of TG-DTA coupled with a programmable humidity controller. With increasing water vapor pressure p(H2O) from 0.8 to 10.6 kPa, a systematic reduction of the reaction temperature of the thermal decomposition was observed as the continuous trend from the previous works at the lower p(H2O). Through a comparative kinetic analysis of the reaction at different p(H2O), a catalytic action of the atmospheric water vapor on the nucleation process at the first half of the reaction was identified as the possible origin of the reduction of the reaction temperature.  相似文献   
10.
A highly convenient method for the synthesis of 2-substituted pyrrole derivatives 7a-c from pyrrole using phosgene was developed. Successively, 7-methyl-6,7-dihydro-1H,5H-pyrrolo[2,3-c]azepine-4,8-dione 1a and 6,7-dihydro-1H,5H-pyrrolo[2,3-c]azepine-4,8-dione 1b (aldisin) were synthesized by phosphorus pentoxide/methanesulfonate and polyphosphoric acid cyclization.  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