全文获取类型
收费全文 | 59篇 |
免费 | 4篇 |
专业分类
化学 | 39篇 |
数学 | 8篇 |
物理学 | 16篇 |
出版年
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2014年 | 2篇 |
2013年 | 6篇 |
2012年 | 2篇 |
2011年 | 2篇 |
2010年 | 3篇 |
2008年 | 2篇 |
2007年 | 6篇 |
2006年 | 2篇 |
2005年 | 1篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1994年 | 1篇 |
1990年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1974年 | 2篇 |
排序方式: 共有63条查询结果,搜索用时 0 毫秒
41.
Derivatives (dinitriles, anhydrides, imides, N-phenylimides) of substituted 1-phenylnaphthalene-2,3-dicarboxylic and 1-phenylphenanthrene-2,3-dicarboxylic acids were prepared by the reactions of 2-bromomethylbenzophenones with various dienophiles. Starting from these derivatives, gallium complexes of substituted tetra-1-phenyl-2,3-naphthalocyanines and tetra(1-phenyl-2,3-phenanthro)porphyrazine were synthesized.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 5, 2005, pp. 841–846.Original Russian Text Copyright © 2005 by Donyagina, Luk”yanets. 相似文献
42.
Complex formation of 3,5,10,12,17,19,24,26-octa(carboxymethoxy)-1,8,15,22-tetraundecylcalix[4]arene (H8X) with Li+, Na+, K+, and NH4
+ ions was studied by 1H NMR spectroscopy and pH-metry in water—DMSO solutions. Binding of one cation occurs during the stepped deprotonation of four carboxymethyl groups in H8X. The K+ ion was found to be bound more efficiently than Li+ and Na+. The further deprotonation to the penta- and hexaanion leads to the coordination with two cations. The most stable binuclear complex is formed with the Li+ ion. 相似文献
43.
Liberman E. Yu. Pod”el’nikova E. S. Simakina E. A. Kon’kova T. V. Kleusov B. S. 《Russian Journal of Applied Chemistry》2019,92(5):655-660
Russian Journal of Applied Chemistry - Method of coprecipitation with a subsequent thermal treatment was used to synthesize highly dispersed Mn2O3-Bi2O3-ZrO2-CeO2 solid solutions. The elemental and... 相似文献
44.
Presented work introduces methods for improving linearity of a heterodyne laser interferometer system. The heterodyne configuration exhibits high potential in demanding applications, like pico/nano positioning. Those applications require superior accuracy, more difficult to obtain in a homodyne configuration of the laser interferometer. The homodyne setup is more susceptible to external light, variation of DC offset and higher noises, especially the 1/f noise. Those issues are filtered out in the heterodyne configuration. The main disadvantage of heterodyne setup are higher measurement nonlinearities. In this paper there are first introduced sources of nonlinearities and their impact on the overall accuracy. According to those findings there are proposed techniques to eliminate error caused by parasite beams, i.e. nonlinearities. Presented method is based on digital signal processing and is reliable and easy to use. In the shown approach the nonlinearities correction is completely automatic. Such system is applicable for X/Y positioning stages. Presented configuration of the laser interferometer is able to track the displacement with 100 pm resolution up to 7 m/s of translation velocity. The resolution can be improved to 10 pm by limitation of maximal velocity. In the paper there is confirmed that errors caused by nonlinearities are in range of ±0.6 nm. Achieved accuracy is comparable to capacitance gauges with presented laser interferometer having much better dynamic range. 相似文献
45.
Conformational analysis of 6,6-biquinolyl and its dication was performed using dipole moments and data from electric and magnetic birefringence. The rotation angles between the quinoline rings for thecis- andtrans-conformers in solution are 50°. The emergence of positive charges on both heteroaromatic rings does not result in noticeable changes in the spatial structure.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 330–332, February, 1994. 相似文献
46.
V. E. Semenov A. E. Nikolaev A. V. Kozlov S. N. Pod”yachev O. A. Lodochnikova O. N. Kataeva Sh. K. Latypov V. S. Reznik 《Russian Journal of Organic Chemistry》2008,44(6):891-900
The structure of a series of macrocyclic compounds consisting of a pyrimidine or 1,3,5-triazine ring and an aza-or thiapolymethylene bridge connecting the N1 and N3 atoms of the heteroring is discussed. Some macroheterocycles undergo methylation at the sulfur atom by the action of methyl p-toluenesulfonate. The length of the polymethylene bridge determines conformation of the macroring. Compounds with a shorter bridge both in crystal and in solution are characterized by closely located structural fragments, while extension of the polymethylene chain gives rise to an unfolded structure. Conformational changes in solution are promoted by protonation of the bridging nitrogen atom, and deprotonation restores the initial structure of the macroring. The basicity of the bridging nitrogen atom depends on the geometric parameters of the macroring. 相似文献
47.
48.
Prediction of polymer properties using infinite chain descriptors (ICD) and machine learning: Toward optimized dielectric polymeric materials
下载免费PDF全文
![点击此处可从《Journal of Polymer Science.Polymer Physics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
49.
50.
B. P. Voznyuk N. A. Lesnik Yu. A. Pod’yelets V. N. Pushkar 《Hyperfine Interactions》1990,59(1-4):361-363
The longitudinal relaxation process in thin59Co films with different domain vall percentages has been investigate using a spin-echo technique at room temperature. It has
been obtained that the HHR signal decay behaviour did not depend on the domain wall effects. 相似文献