全文获取类型
收费全文 | 2961篇 |
免费 | 209篇 |
国内免费 | 17篇 |
专业分类
化学 | 2088篇 |
晶体学 | 9篇 |
力学 | 80篇 |
数学 | 468篇 |
物理学 | 542篇 |
出版年
2023年 | 49篇 |
2022年 | 46篇 |
2021年 | 67篇 |
2020年 | 130篇 |
2019年 | 145篇 |
2018年 | 68篇 |
2017年 | 46篇 |
2016年 | 149篇 |
2015年 | 132篇 |
2014年 | 130篇 |
2013年 | 186篇 |
2012年 | 243篇 |
2011年 | 257篇 |
2010年 | 132篇 |
2009年 | 97篇 |
2008年 | 173篇 |
2007年 | 130篇 |
2006年 | 115篇 |
2005年 | 142篇 |
2004年 | 88篇 |
2003年 | 75篇 |
2002年 | 59篇 |
2001年 | 31篇 |
2000年 | 35篇 |
1999年 | 30篇 |
1998年 | 20篇 |
1997年 | 16篇 |
1996年 | 23篇 |
1995年 | 23篇 |
1994年 | 19篇 |
1993年 | 19篇 |
1992年 | 10篇 |
1991年 | 8篇 |
1989年 | 13篇 |
1988年 | 9篇 |
1985年 | 10篇 |
1984年 | 8篇 |
1983年 | 12篇 |
1982年 | 12篇 |
1981年 | 8篇 |
1979年 | 10篇 |
1978年 | 15篇 |
1977年 | 10篇 |
1976年 | 8篇 |
1975年 | 11篇 |
1973年 | 7篇 |
1972年 | 9篇 |
1971年 | 8篇 |
1970年 | 9篇 |
1967年 | 7篇 |
排序方式: 共有3187条查询结果,搜索用时 15 毫秒
1.
Interactions of Pt‐ttpy with G‐Quadruplexes Originating from Promoter Region of the c‐myc Gene Deciphered by NMR and Gel Electrophoresis Analysis
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
2.
If the Riemann–Christoffel tensor associated with a field of class of positive definite symmetric matrices of order three vanishes in a connected and simply connected open subset , then this field is the metric tensor field associated with a deformation of class of the set , uniquely determined up to isometries of . We establish here that the mapping defined in this fashion is continuous, for ad hoc metrizable topologies. To cite this article: P.G. Ciarlet, F. Laurent, C. R. Acad. Sci. Paris, Ser. I 335 (2002) 489–493. 相似文献
3.
4.
We obtain asymptotic formulas for all the moments of certain arithmetic functions with linear recurrence sequences. We also apply our results to obtain asymptotic formulas for some mean values related to average orders of elements in finite fields. 相似文献
5.
O. Životský K. Postava L. Kraus M. Foldyna J. Pištora 《Journal of magnetism and magnetic materials》2006
In this paper we investigate the surface magnetic properties of as-quenched (AQ) CoFeCrBSi ribbons prepared by planar flow casting method with using magneto-optic Kerr effect (MOKE). Measured hysteresis loops in longitudinal and transversal configurations enable us to obtain the information of ribbons surface magnetic properties. Moreover, we suggest new magneto-optic method, which is based on measurements of magneto-optical effects depending on DC current flowing through the ribbon. Experimental data of AQ ribbons are then compared with the model, which describes the influence of incidence angle on magneto-optical angles. 相似文献
6.
7.
8.
The non-linear distribution of lattice strain
310vs sin2
observed on the surface of a polished steel specimen can be interpreted by tri-axial stress state with surface components of stress tensor
11(0)=
22(0) and gradientsg
11=
11/T, g
33=
33/T. The distribution of experimental values
is duscussed from the viewpoint of various ways of calculating
11.The authors would like to thank Dr. J. Musil, D. Sc. of the Institute of Physics of Czechoslovak Academy of Sciences for kindly providing the samples which made possible this study. 相似文献
9.
Miscibility relationships in four-component systems containing sodium alkylbenzenesulfonates, toluene, n-butanol, and water were studied at 25°C in the hope of clarifying the complex systems used in the “micellar flood” enhanced oil recovery process. Phase boundary curves for the pseudo three-component systems (constant sulfonate/water ratios, 2.5 moles sulfonate per kg water) were determined. The sulfonates included those of benzene, toluene, xylene, ethylbenzene, isopropylbenzene, mesitylene, cymene, methyl-t-butylbenzene, and diisopropylbenzene, in all of which the alkyl substituents are smaller than in the usual surfactants. The phase boundary curves have similar and fairly symmetrical shapes. The amount of n-butanol (cosolvent) required to produce miscibility decreases with increasing number of alkyl carbons on the benzene ring of the sulfonates and seems relatively independent of the isomeric structure. The sodium salt of diisopropylbenzenesulfonate gives the lowest phase boundary curve (least n-butanol required for miscibility) among the nine sulfonates studied. 相似文献
10.
Wendelin Winfried Knotz Florian Schramm Hans-Wolfgang 《Monatshefte für Chemie / Chemical Monthly》1975,106(1):159-168
Monatshefte für Chemie - Chemical Monthly - Primary, secondary and tertiary aliphatic alcohols quickly react with 1-chloromethyl-isatin (1) to give good yields of alkoxymethylisatines4-novel... 相似文献