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   201篇
  免费   7篇
  国内免费   1篇
化学   145篇
晶体学   2篇
力学   4篇
数学   23篇
物理学   35篇
  2024年   2篇
  2023年   1篇
  2022年   7篇
  2021年   14篇
  2020年   5篇
  2019年   16篇
  2018年   9篇
  2017年   6篇
  2016年   6篇
  2015年   6篇
  2014年   13篇
  2013年   20篇
  2012年   10篇
  2011年   23篇
  2010年   12篇
  2009年   4篇
  2008年   8篇
  2007年   5篇
  2006年   9篇
  2005年   5篇
  2004年   1篇
  2003年   4篇
  2002年   2篇
  2001年   1篇
  2000年   1篇
  1996年   2篇
  1995年   3篇
  1993年   2篇
  1991年   2篇
  1990年   3篇
  1984年   2篇
  1983年   1篇
  1979年   1篇
  1975年   1篇
  1972年   1篇
  1968年   1篇
排序方式: 共有209条查询结果,搜索用时 15 毫秒
1.
Hydroxyapatite (HA), a natural constituent of bone, was synthesized. HA particles were radiolabeled with 188Re. Radiolabeling efficiency was 95%. In vitro studies showed 5% loss of activity from particles in normal saline over a period of 2 days, whereas a dissociation rate of 9% was observed in human serum albumin.  相似文献   
2.
Acta Mathematica Sinica, English Series - In this research article, we shall give some reverse Arithmetic-Geometric mean inequalities for unital positive linear maps on Hilbert space operators...  相似文献   
3.
Coset diagrams for the orbit of the groupG=〈x,y∶x 2=y 4 =1〉 acting on real quadratic fields give some interesting information. By using these coset diagrams, we show that in the orbitpG, where , the non-square positive integern does not change its value and the real quadratic irrational numbers of the formp, wherep and its algebraic conjugate have different signs, are finite in number and that part of the coset diagram containing such numbers forms a single closed path, which is the only closed path in the orbit ofp.  相似文献   
4.
Summary The lyophilized MIBI kit was dissolved in 1 ml sterile saline or 250<span style='font-size: 12.0pt;font-family:Symbol;mso-bidi-font-family:Symbol'>mg/ml ascorbic acid and dispensed into 0.2 ml fractions, which were stored at -20 °C for 12 days. The solution was prepared by using two different protection methods. In the first method evacuated vials were used for storage of fractionated solution while in the second method an antioxidant agent, ascorbic acid was employed. The radiochemical impurity of 99mTc-MIBI in the unprotected fractions rises with time. Exclusion of air as well addition of ascorbic acid in fractionated solutions gave very good results. The labeling efficiency and biodistribution of fractionated solutions was the same as the lyophilized kit even after 12 days.  相似文献   
5.
Structural and dynamical properties of Zn(II) in aqueous solution were investigated, based on an ab initio quantum mechanical/molecular mechanical (QM/MM) molecular dynamics simulation at double-zeta Hartree-Fock quantum mechanical level including the first and second hydration shells into the QM region. The inclusion of the second shell in the QM region resulted in significant changes in the properties of the hydrate. The first shell coordination number was found to be 6, the second shell consists of approximately 14 water molecules. The structural properties were determined in terms of RDF, ADF, tilt and theta angle distributions, while dynamics were characterized by mean ligand residence times, ion-ligand stretching frequencies and the vibrational and librational motions of water ligands.  相似文献   
6.
A new series of 4-(4'-chlorophenyl)-4-hydroxypiperidine derivatives (2-5), substituted at nitrogen, were synthesized and tested as potential analgesic compounds as well as evaluated for their effect on hypotensive activity. Results showed that all the derivatives exhibit significant analgesic activity in male Wistar rats at a dose of 50 mg/kg of body weight after intramuscular injection, when tested by thermal stimuli (tail flick test). Pethidine was used as reference drug. Compounds 2, 3 and 5 produced reduction in blood pressure in normotensive rat.  相似文献   
7.
The review considers recent advances in using diethanolamine (DEA) in the synthesis of amides, polymerization reactions, and synthesis of heterocycles, crown ethers, Mannich bases, and ionic liquids. Biological activity of DEA and its derivatives is also reviewed.  相似文献   
8.
9.
Molecular Diversity - The terminal oxidases of the oxidative phosphorylation pathway play a significant role in the survival and growth of M. tuberculosis, targeting these components lead to...  相似文献   
10.
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