全文获取类型
收费全文 | 571篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
化学 | 383篇 |
晶体学 | 4篇 |
力学 | 23篇 |
数学 | 78篇 |
物理学 | 91篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 31篇 |
2021年 | 32篇 |
2020年 | 19篇 |
2019年 | 24篇 |
2018年 | 18篇 |
2017年 | 12篇 |
2016年 | 20篇 |
2015年 | 21篇 |
2014年 | 18篇 |
2013年 | 43篇 |
2012年 | 33篇 |
2011年 | 33篇 |
2010年 | 26篇 |
2009年 | 16篇 |
2008年 | 28篇 |
2007年 | 35篇 |
2006年 | 29篇 |
2005年 | 17篇 |
2004年 | 17篇 |
2003年 | 18篇 |
2002年 | 20篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1981年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有579条查询结果,搜索用时 15 毫秒
41.
Dariusz Basiak Wanda Ziemkowska Paweł Socha Łukasz Dobrzycki Zbigniew Ochal Edyta Pindelska 《Journal of Coordination Chemistry》2017,70(9):1528-1535
2-Mercapto-1,3-benzothiazole (mbztH) may act as a chelating or bridging ligand. In this study, reactions of mbztH with Me3Ga and Me3In were examined. The products were characterized by NMR spectroscopy, elemental analyses, melting point, and molecular weight determinations. Formation of mononuclear chelating complexes Me2M(mbzt) (M = Ga, In) was observed in solutions. Crystallization of Me2M(mbzt) yielded uncommon non-symmetrical dinuclear complexes Me4M2(mbzt)2, in which one metal is bonded to two sulfurs and the other to two nitrogens. 相似文献
42.
JPC – Journal of Planar Chromatography – Modern TLC - 相似文献
43.
Nataliya Chumalo Galyna P. Nychyporuk Rainer Pöttgen Dariusz Kaczorowski 《Journal of solid state chemistry》2010,183(12):2963-2967
The indides Ce7Ni5±xGe3±xIn6 and Pr7Ni5±xGe3±xIn6 were synthesized from the elements by arc-melting of the components. Single crystals were grown via special annealing sequences. Both structures were solved from X-ray single crystal diffraction data: new structure type, P6/m, Z=1, a=11.385(2), c=4.212(1) Å, wR2=0.0640, 634F2 values, 25 variables for Ce7Ni4.73Ge3.27In6 and a=11.355(6), c=4.183(2) Å, wR2=0.0539, 563F2 values, 25 variables for Pr7Ni4.96Ge3.04In6. Both indides show homogeneity ranges through Ni/Ge mixing (M sites). This new structure type can be derived from the AlB2 structure type by a substitution of the Al and B atoms by CeM12 and NiIn6Ce3 polyhedra (tricapped trigonal prism). Magnetic susceptibility measurements on a polycrystalline sample of Ce7Ni5Ge3In6 indicated Curie-Weiss like paramagnetic behavior down to 1.71 K with the effective magnetic moment slightly reduced in relation to the value expected for trivalent cerium ions. No magnetic ordering is evident. 相似文献
44.
Emilia Styczeń Zygmunt Warnke Dariusz Wyrzykowski Julia K?ak Jerzy Mroziński Artur Sikorski 《Structural chemistry》2010,21(1):269-276
The crystal structures of tetrabromocobaltate(II) and tetrabromomanganate(II) salts of general formula [(C2H5)4N]2[CoBr4] (1) and [(C4H9)4N]2[MnBr4] (2) were determined. The manganese and cobalt cations are four-coordinated by bromide anions and they adopt a slightly distorted
tetrahedral coordination. In the structure of both compounds there are neither hydrogen bonds nor any unusual short-range intermolecular interactions. Magnetic measurements of the powdered samples gave negative values of the Weiss constants
equal to −4.9 and −1.1 K for (1) and (2), respectively, which suggest antiferromagnetic interactions to be transferred within the crystal lattice. 相似文献
45.
Xiao-Xiong Gan Dariusz Bugajewski 《Bulletin of the Brazilian Mathematical Society》2011,42(3):415-437
Several kinds of formal Laurent series have been introduced with some restrictions so far. This paper systematically sets
up a natural definition and structure of formal Laurent series without those restrictions, including introducing a multiplication
between formal Laurent series. This paper also provides some results on the algebraic structure of the space of formal Laurent
series, denoted by
\mathbbL\mathbb{L}. By means of the results of the generalized composition of formal power series, we define a composition of a Laurent series
with a formal power series and provide a necessary and sufficient condition for the existence of such compositions. The calculus
about formal Laurent series is also introduced. 相似文献
46.
This paper presents a system that accurately measures the distance travelled by ultrasound waves through the air. The simple design of the system and its obtained accuracy provide a tool for non-contact distance measurements required in the laser’s optical system that investigates the surface of the eyeball. 相似文献
47.
Stratified materials are of great importance for many branches of modern industry, e.g. electronics or optics and for biomedical applications. Examination of chemical composition of individual layers and determination of their thickness helps to get information on their properties and function. A confocal 3D micro X‐ray fluorescence (3D µXRF) spectroscopy is an analytical method giving the possibility to investigate 3D distribution of chemical elements in a sample with spatial resolution in the micrometer regime in a non‐destructive way. Thin foils of Ti, Cu and Au, a bulk sample of Cu and a three‐layered sandwich sample, made of two thin Fe/Ni alloy foils, separated by polypropylene, were used as test samples. A Monte Carlo (MC) simulation code for the determination of elemental concentrations and thickness of individual layers in stratified materials with the use of confocal 3D µXRF spectroscopy was developed. The X‐ray intensity profiles versus the depth below surface, obtained from 3D µXRF experiments, MC simulation and an analytical approach were compared. Correlation coefficients between experimental versus simulated, and experimental versus analytical model X‐ray profiles were calculated. The correlation coefficients were comparable for both methods and exceeded 99%. The experimental X‐ray intensity profiles were deconvoluted with iterative MC simulation and by using analytical expression. The MC method produced slightly more accurate elemental concentrations and thickness of successive layers as compared to the results of the analytical approach. This MC code is a robust tool for simulation of scanning confocal 3D µXRF experiments on stratified materials and for quantitative interpretation of experimental results. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
48.
Summary We prove the existence of martingale solutions and of stationary solutions of stochastic Navier-Stokes equations under very general hypotheses on the diffusion term. The stationary martingale solutions yield the existence of invariant measures, when the transition semigroup is well defined. The results are obtained by a new method of compactness. 相似文献
49.
50.