全文获取类型
收费全文 | 344篇 |
免费 | 6篇 |
国内免费 | 3篇 |
专业分类
化学 | 247篇 |
晶体学 | 7篇 |
力学 | 1篇 |
数学 | 18篇 |
物理学 | 80篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 8篇 |
2015年 | 3篇 |
2014年 | 5篇 |
2013年 | 21篇 |
2012年 | 11篇 |
2011年 | 16篇 |
2010年 | 10篇 |
2009年 | 6篇 |
2008年 | 23篇 |
2007年 | 16篇 |
2006年 | 15篇 |
2005年 | 12篇 |
2004年 | 14篇 |
2003年 | 16篇 |
2002年 | 21篇 |
2001年 | 7篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1997年 | 9篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1990年 | 5篇 |
1988年 | 2篇 |
1986年 | 4篇 |
1985年 | 7篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1974年 | 7篇 |
1973年 | 2篇 |
1968年 | 3篇 |
1967年 | 1篇 |
1962年 | 1篇 |
1959年 | 2篇 |
1937年 | 1篇 |
排序方式: 共有353条查询结果,搜索用时 218 毫秒
81.
A cation-exchange method was used for determining the stability constants of complexes formed between Bi/III/, present in tracer concentrations /ca. 10–11M Bi/, and nitrate ion or chloride ion in 1.OM H/ClO4, NO3/ or 1.OM H/Cl, ClO4/ solutions, respectively. The successive formation constants were calculated using the distribution data. The resulting 1g 1, 1g 2, and 1g 3 values were 0.74, 1.22, and 1.54 for 1.OM H/ClO4, NO3/ solutions, and 2.36, 3.61, and 4.95 for 1.OM H/Cl, ClO4/ solutions, respectively. 相似文献
82.
83.
T. Omori K. Nagasaki E. Watanabe H. Suganuma 《Journal of Radioanalytical and Nuclear Chemistry》1997,220(1):37-40
A new spectrophotometric determination of technetium has been developed by means of the solvent extraction of tris(1,10-phenanthroline)iron(II) ([Fe(phen)3
2+]) with pertechnetate into nitrobenzene. The concentration of technetium can be determined by measuring the characteristic absorbance at 516 nm (=11,700M–1·cm–1) in the organic phase. An important feature of the proposed method is that the concentration of pertechnetate can be determined without complicated processes such as the reduction of pertechnetate and the subsequent formation of a colored chelate. 相似文献
84.
M. Arisaka N. Takuwa H. Suganuma 《Journal of Radioanalytical and Nuclear Chemistry》2000,245(3):469-473
The stability constants (1(F)) of the monofluoro complex of Lu(III) and those (1(Cl)) of the monochloride solvent-shared ion-pair of Lu(III) have been determined in mixed solvents of methanol and water at 0.10 and 1.00 mol·dm–3 ionic strengths, respectively. The variation in ln1(F) with an increase in the mole fraction of methanol (X
s) in the mixed solvent system showed an acute-angled convex inflection point at X
s 0.12, an acute-angled concave inflection point at X
s 0.22, and another acute-angled convex inflection point at X
s 0.27. It was concluded that the first and the second convex inflection points denoted the CN of Lu3+ from CN = 8 to a mixture of CN = 8 and 7 and from CN = 8 and 7 to a mixture containing CN = 6, respectively. The concave point is the starting point of a change in the CN of Lu(III) in LuF2+ from CN = 8 to a mixture of CN = 8 and 7. The values of two inflection points of the CN around Lu3+ are consistent with the inflection points of the variation in the values of ln1(Cl) versus the dielectric constant of the mixed solvent. 相似文献
85.
J. Kamishima T. Ogi R. Minayoshi N. Kinugawa H. Suganuma M. Noguchi K. Ishikawa M. Yanaga 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(2):419-422
Eleven elements in hepatocyte of mice fed with zinc deficient diet and those fed with control diet were determined by INAA.
Zinc concentration, especially, in cytosolic fraction of zinc deficient mice was lower than that of control ones. On the other
hand, cobalt concentrations in all fractions of zinc deficient mice were higher than those of control ones. However, when
SDS-PAGE was performed for cytosolic fraction of hepatic cells, the positions and the number of the protein bands on gel developed
for zinc deficient mice were not different from those for control ones. 相似文献
86.
87.
88.
Enhancement of the Catalytic Activity of Chiral H8‐BINOL Titanium Complexes by Introduction of Sterically Demanding Groups at the 3‐Position
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yasuki Hayashi Nobuaki Yamamura Prof. Dr. Takahiro Kusukawa Prof. Dr. Toshiro Harada 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(34):12095-12105
The activity of chiral titanium catalysts derived from H8‐BINOL ligands in the enantioselective arylation of an aldehyde with PhTi(OiPr)3 is significantly enhanced by an increase of the size of the substituent at the 3‐position. High enantioselectivity (> 90 % ee) can be obtained even at a substrate/catalyst ratio (S/C) of 800 for DTBP‐H8‐BINOL (DTBP=3,5‐di‐tert‐butylphenyl) and DAP‐H8‐BINOL (DAP=3,5‐di(9‐anthraceny)phenyl). These titanium catalysts are successfully applied to the enantioselective arylation and heteroarylation of aldehydes at a S/C ratio of 400 by using organotitanium reagents generated in situ from bromide precursors. The remarkable weakening of the intramolecular aggregation of the two ?Ti(OiPr)3 units in a DPP‐H8‐BINOL (DPP=3,5‐diphenylpheny)‐derived bis‐titanium complex is revealed by X‐ray and variable‐temperature (VT)‐NMR studies. Based on these observations, a catalytic cycle, involving the rate‐limiting aryl group transfer followed by aldehyde complexation and enantioselective arylation, is proposed to account for the high activity of the 3‐substituted H8‐BINOL catalyst system. 相似文献
89.
90.
Representation of Multicomponent Liquid-Liquid Equilibria for Aqueous and Organic Solutions Using a Modified UNIQUAC Model 总被引:6,自引:0,他引:6
Kazuhiro Tamura Yao Chen Kaoru Tada Toshiro Yamada Isamu Nagata 《Journal of solution chemistry》2000,29(5):463-488
A modified form of the UNIQUAC model is presented to accurately reproducebinary phase equilibria and ternary and quaternary liquid-liquid equilibria ofaqueous and organic solutions. The model gives a good representation in thereproduction of binary coexistence curves over a wide temperature range usingtemperature-dependent parameters and of binary vapor-liquid equilibria usingtwo binary energy parameters, and in the correlation of ternary and quaternaryliquid-liquid equilibria using ternary and quaternary parameters, in addition tobinary parameters. The quaternary calculated results are compared with thoseobtained from the modified Wilson and extended UNIQUAC models. 相似文献