全文获取类型
收费全文 | 828篇 |
免费 | 32篇 |
国内免费 | 3篇 |
专业分类
化学 | 650篇 |
晶体学 | 33篇 |
力学 | 12篇 |
数学 | 37篇 |
物理学 | 131篇 |
出版年
2022年 | 16篇 |
2021年 | 13篇 |
2020年 | 10篇 |
2019年 | 14篇 |
2018年 | 26篇 |
2017年 | 13篇 |
2016年 | 14篇 |
2015年 | 26篇 |
2014年 | 18篇 |
2013年 | 63篇 |
2012年 | 46篇 |
2011年 | 42篇 |
2010年 | 25篇 |
2009年 | 24篇 |
2008年 | 37篇 |
2007年 | 51篇 |
2006年 | 38篇 |
2005年 | 38篇 |
2004年 | 29篇 |
2003年 | 23篇 |
2002年 | 41篇 |
2001年 | 21篇 |
2000年 | 17篇 |
1999年 | 9篇 |
1998年 | 11篇 |
1997年 | 11篇 |
1996年 | 9篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 8篇 |
1992年 | 19篇 |
1991年 | 11篇 |
1990年 | 13篇 |
1989年 | 14篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1984年 | 14篇 |
1983年 | 15篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1969年 | 2篇 |
排序方式: 共有863条查询结果,搜索用时 31 毫秒
81.
Natarajan Raman Ramaraj Jeyamurugan Mariyyappan Subbulakshmi Raja Boominathan Chithu Ramakrishnan Yuvarajan 《Chemical Papers》2010,64(3):318-328
A novel series of Co(II), Ni(II), Cu(II), Zn(II), and VO(IV) complexes has been synthesized from the Schiff base derived from
4-[(3,4-dimethoxybenzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one and 1,2-diaminobenzene. Structural features
were determined by analytical and spectral techniques. Binding of synthesized complexes with calf thymus DNA (CT DNA) was
studied by spectroscopic methods and viscosity measurements. Experimental results indicate that the complexes are able to
form adducts with DNA and to distort the double helix by changing the base stacking. Lower DNA affinity of the VO(IV) complex
is caused by the change of coordination geometry by the vanadyl ion resulting in a somewhat unfavorable configuration for
the DNA binding. Oxidative DNA cleavage activities of the complexes were studied with supercoiled (SC) pUC19 DNA using gel
electrophoresis; the mechanism studies revealed that the hydroxyl radical is likely to be the reactive species responsible
for the cleavage of pUC19 DNA by the synthesized complexes. The in vitro antimicrobial screening effects of the investigated
compounds were monitored by the disc diffusion method. The synthesized Schiff base complexes exhibit higher antimicrobial
activity than the respective free Schiff base. 相似文献
82.
Ponnusamy Sami Kandasamy Venkateshwari Natarajan Mariselvi Arunachalam Sarathi Kasi Rajasekaran 《Transition Metal Chemistry》2010,35(2):137-142
l-cysteine undergoes facile electron transfer with heteropoly 10-tungstodivanadophosphate,
[ \textPV\textV \textV\textV \textW 1 0 \textO 4 0 ]5 - , \left[ {{\text{PV}}^{\text{V}} {\text{V}}^{\text{V}} {\text{W}}_{ 1 0} {\text{O}}_{ 4 0} } \right]^{5 - } , at ambient temperature in aqueous acid medium. The stoichiometric ratio of [cysteine]/[oxidant] is 2.0. The products of the
reaction are cystine and two electron-reduced heteropoly blue, [PVIVVIVW10O40]7−. The rates of the electron transfer reaction were measured spectrophotometrically in acetate–acetic acid buffers at 25 °C.
The orders of the reaction with respect to both [cysteine] and [oxidant] are unity, and the reaction exhibits simple second-order
kinetics at constant pH. The pH-rate profile indicates the participation of deprotonated cysteine in the reaction. The reaction
proceeds through an outer-sphere mechanism. For the dianion −SCH2CH(NH3
+)COO−, the rate constant for the cross electron transfer reaction is 96 M−1s−1 at 25 °C. The self-exchange rate constant for the
- \textSCH2 \textCH( \textNH3 + )\textCOO - \mathord