全文获取类型
收费全文 | 9438篇 |
免费 | 312篇 |
国内免费 | 7篇 |
专业分类
化学 | 4981篇 |
晶体学 | 62篇 |
力学 | 226篇 |
数学 | 2048篇 |
物理学 | 2440篇 |
出版年
2022年 | 76篇 |
2021年 | 111篇 |
2020年 | 155篇 |
2019年 | 149篇 |
2018年 | 174篇 |
2017年 | 179篇 |
2016年 | 371篇 |
2015年 | 327篇 |
2014年 | 385篇 |
2013年 | 682篇 |
2012年 | 467篇 |
2011年 | 622篇 |
2010年 | 362篇 |
2009年 | 327篇 |
2008年 | 348篇 |
2007年 | 314篇 |
2006年 | 239篇 |
2005年 | 130篇 |
2004年 | 161篇 |
2003年 | 165篇 |
2002年 | 171篇 |
2001年 | 124篇 |
2000年 | 140篇 |
1999年 | 120篇 |
1998年 | 125篇 |
1997年 | 107篇 |
1996年 | 101篇 |
1995年 | 82篇 |
1994年 | 89篇 |
1993年 | 88篇 |
1992年 | 90篇 |
1991年 | 78篇 |
1990年 | 96篇 |
1989年 | 80篇 |
1988年 | 82篇 |
1987年 | 74篇 |
1985年 | 100篇 |
1984年 | 117篇 |
1983年 | 72篇 |
1982年 | 92篇 |
1981年 | 96篇 |
1980年 | 84篇 |
1979年 | 101篇 |
1978年 | 96篇 |
1977年 | 85篇 |
1976年 | 115篇 |
1975年 | 98篇 |
1974年 | 97篇 |
1973年 | 74篇 |
1968年 | 74篇 |
排序方式: 共有9757条查询结果,搜索用时 15 毫秒
51.
Miloslav Duchoň Anatolij Dvurečenskij Paolo de Lucia 《International Journal of Theoretical Physics》1997,36(9):1941-1958
We present a solution to the moment problem for effect algebras, concerning mean values of all powers of an observable concentrated
on the interval [0, 1] for states from a convex set. We give a solution for particular examples, e.g., for the set of all
effect operators. We examine how this problem is related to a socalled E-property. Finally, we give a solution for observables
studied in the operational approach to physical theories. 相似文献
52.
Dislocation motion in the real lattice of alloys is highly complex. In a certain temperature range the dynamic strain ageing phenomena have been reported. In this paper the influence of mobile solute atoms (as obstacles) on the motion of dislocation is analysed. Both processes are assumed to be thermally activated. A new model based on this assumption is proposed. The dislocation velocity and the friction stress (due to solute-dislocation interactions) are calculated. A change in the friction stress caused by solute mobility is discussed. 相似文献
53.
54.
Marko D. Mihovilovic Bernhard Müller Markus Spina Arjumand I. Durrani Peter Stanetty Georg Dazinger Karl Kirchner 《Monatshefte für Chemie / Chemical Monthly》2006,137(6):785-794
Summary. Recombinant Escherichia coli overexpressing Pseudomonas sp. NCIMB 9872 cyclopentanone monooxygenase (CPMO, EC 1.14.13.16) and Acinetobacter sp. NCIMB 9871 cyclohexanone monooxygenase (CHMO, EC 1.14.13.22) have been utilized in whole-cell Baeyer-Villiger biotransformations of prochiral bicycloketones. A significant difference in substrate acceptance and stereoselectivity was
observed for bicyclo[3.3.0] and bicyclo[4.3.0] substrates. A plausible mechanism of these transformations was established
by means of high level DFT/B3LYP calculations suggesting an essential difference in electronic requirements for a successful
enzymatic conversion, which was similarly encountered in recombinant whole-cell mediated biooxidations. Some of the lactones
produced in the biocatalytic Baeyer-Villiger oxidation represent key intermediates for the synthesis of indole alkaloids. 相似文献
55.
56.
Š. Jakševičius 《Lithuanian Mathematical Journal》1992,32(2):174-180
Kaunas Academy of Agriculture, 4324 Noreikiškés, Lithuania. Translated from Lietuvos Matematikos Rinkinys, Vol. 32, No. 2,
pp. 221–228, April–June, 1992. 相似文献
57.
58.
The paper is devoted to the research of large deviation probabilities in the approximation by compound Poisson law. 相似文献
59.
Oriňák Andrej Arlinghaus Heinrich Frank Vering Guido Justinová Martina Oriňáková Renáta Turčániová L’udmila Halama Maroš 《平面色谱法杂志一现代薄层色谱法》2003,16(1):23-27
JPC – Journal of Planar Chromatography – Modern TLC - Two interfaces have been tested for coupling thin-layer chromatography (TLC) with time-of-flight secondary-ion mass spectrometry... 相似文献
60.
The effective signal in x-ray diffraction analysis of material properties often contains high frequency (noise) and low frequency
(trend) components as additive parts. It is necessary to extract the effective signal from the noise to ensure high quality
of signal processing. Digital filters of Volterra type are proposed for filtering purposes and a comparison of Volterra filtration
implemented on x-ray diffraction data versus results from a set of other digital filters is given. 相似文献