全文获取类型
收费全文 | 131篇 |
免费 | 6篇 |
国内免费 | 2篇 |
专业分类
化学 | 99篇 |
晶体学 | 13篇 |
数学 | 1篇 |
物理学 | 26篇 |
出版年
2023年 | 1篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 8篇 |
2013年 | 12篇 |
2012年 | 14篇 |
2011年 | 12篇 |
2010年 | 2篇 |
2009年 | 3篇 |
2007年 | 2篇 |
2006年 | 2篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2002年 | 5篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1995年 | 5篇 |
1992年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 6篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1966年 | 1篇 |
1964年 | 2篇 |
1940年 | 1篇 |
1934年 | 1篇 |
1915年 | 1篇 |
1912年 | 2篇 |
排序方式: 共有139条查询结果,搜索用时 15 毫秒
81.
82.
Robert Kretschmer 《Nachrichten aus der Chemie》2012,60(4):449-450
83.
PM Scheifele MT Johnson L Kretschmer JG Clark D Kemper G Potty 《The Journal of the Acoustical Society of America》2012,132(2):EL88-EL94
Underwater and in-air noise evaluations were completed in performance pool systems at Georgia Aquarium under normal operating conditions and with performance sound tracks playing. Ambient sound pressure levels at in-pool locations, with corresponding vibration measures from life support system (LSS) pumps, were measured in operating configurations, from shut down to full operation. Results indicate noise levels in the low frequency ranges below 100?Hz were the highest produced by the LSS relative to species hearing thresholds. The LSS had an acoustic impact of about 10?dB at frequencies up to 700?Hz, with a 20?dB re 1?μPa impact above 1000?Hz. 相似文献
84.
85.
86.
Krieck S Kretschmer R Görls H Westerhausen M 《Journal of the American Chemical Society》2011,133(18):6960-6963
The reaction of 1,2-diphenylbenzene with rubidium metal in THF yields extremely sensitive and pyrophoric [η(5)-{1,2-diphenyl-2,5-cyclohexadienyl}rubidium](∞) (1). Compound 1 characterizes a possible intermediate in a Birch-type reaction and represents a very rare example of a fully characterized organorubidium complex as well as an open main-group metal pentadienide as part of a six-membered ring. In the solid state the rubidium atoms interact with the cyclohexadienyl moiety, whereas the coordination sphere of the soft cation is additionally stabilized exclusively by several metal π-arene interactions despite the presence of strongly coordinating donors. The bonding situation was elucidated by MP2/def2-TZVPP calculations including population analysis. 相似文献
87.
Jun-Teng Huang Xiang-Li Wang Yang Zhang Mian HR Mahmood Yan-Yuan Huang Xiao Ying Liang-Nian Ji Hai-Yang Liu 《Transition Metal Chemistry》2013,38(3):283-289
The interaction of a water-soluble sulfonated Mn(III) corrole Mn(tpfc)(SO3Na)2 [tpfc = 5,10,15-tris(pentafluorophenyl)corrole] with calf thymus DNA (ct-DNA) has been studied by spectroscopic methods, and the nuclease activity of this complex has also been examined by agarose gel electrophoresis. Mn(tpfc)(SO3Na)2 exhibits weak aggregation tendency in buffer solution and can bind to ct-DNA via an outside binding mode with a binding constant of 1.25 × 104 M?1. The observed increase in Stern–Volmer quenching constant with increasing temperature indicates that the competition of the manganese corrole and ethidium bromide with ct-DNA is a dynamic process. Moreover, the manganese corrole displays good chemical nuclease activity in the presence of hydrogen peroxide via oxidative cleavage of DNA. 相似文献
88.
Dr. Manuel Kretschmer Dr. Michael Dieckmann Prof. Dr. Pengfei Li Dr. Sven Rudolph Dipl.‐Chem. Daniel Herkommer Dr. Johannes Troendlin Prof. Dr. Dirk Menche 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(47):15993-16018
A highly convergent total synthesis of the potent polyketide macrolide rhizopodin has been achieved in 29 steps by employing a concise strategy that exploits the molecule′s C2 symmetry. Notable features of this convergent approach include a rapid assembly of the macrocycle through a site‐directed sequential cross‐coupling strategy and the bidirectional attachment of the side chains by means of Horner–Wadsworth–Emmons (HWE) coupling reactions. During the course of this endeavor, scalable routes for synthesis of three main building blocks of similar complexity were developed that allowed for their stereocontrolled construction. This modular route will be amenable to the development of syntheses of other analogues of rhizopodin. 相似文献
89.
通过间苯二甲醛与5-氟苯基二吡咯甲烷反应合成了一种新的间位苯基桥联的双咔咯1,并利用锰盐与自由咔咯反应制备了其锰的金属配合物2。采用紫外、质谱、核磁、XPS等手段对化合物进行了表征。以苯乙烯为底物考察了锰双咔咯2的催化氧化性质,探讨了时间、溶剂、氧源、轴向配体对催化反应的影响。结果表明以亚碘酰苯和间氯过氧苯甲酸为氧源时催化的主要产物为环氧苯乙烷,而以双氧水和叔丁基过氧化氢为氧源时则主要产物为苯甲醛;在极性溶剂中的催化氧化产率较高。轴向配体对催化氧化有促进作用,不同轴向配体对催化反应产率提高的顺序是:1-甲基咪唑吡啶咪唑。 相似文献
90.
N. Krumbholz T. Hochrein N. Vieweg T. Hasek K. Kretschmer M. Bastian M. Mikulics M. Koch 《Polymer Testing》2009,28(1):30-35
We demonstrated the potential of terahertz spectroscopy for contactless and nondestructive inline control of polymeric compounding processes. Using a fiber-coupled terahertz spectrometer, we investigated molten polymers and polymeric compounds. On one hand, we studied the influence of temperature and pressure on the terahertz properties of molten polypropylene. On the other hand, various polypropylene–CaCO3 and PA6–glass-fiber compounds were examined. We showed that the volumetric additive content can be determined from the terahertz refractive index of the compound. Real-time measurements demonstrated the applicability of terahertz technology as a valuable tool for the inline control of production processes. 相似文献