全文获取类型
收费全文 | 965篇 |
免费 | 42篇 |
国内免费 | 7篇 |
专业分类
化学 | 519篇 |
晶体学 | 5篇 |
力学 | 55篇 |
数学 | 282篇 |
物理学 | 153篇 |
出版年
2023年 | 12篇 |
2022年 | 20篇 |
2021年 | 30篇 |
2020年 | 27篇 |
2019年 | 22篇 |
2018年 | 15篇 |
2017年 | 13篇 |
2016年 | 54篇 |
2015年 | 39篇 |
2014年 | 48篇 |
2013年 | 76篇 |
2012年 | 88篇 |
2011年 | 63篇 |
2010年 | 45篇 |
2009年 | 39篇 |
2008年 | 55篇 |
2007年 | 44篇 |
2006年 | 44篇 |
2005年 | 21篇 |
2004年 | 32篇 |
2003年 | 40篇 |
2002年 | 20篇 |
2001年 | 13篇 |
2000年 | 11篇 |
1999年 | 13篇 |
1998年 | 11篇 |
1997年 | 8篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 8篇 |
1984年 | 10篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1969年 | 2篇 |
1924年 | 2篇 |
1911年 | 2篇 |
1897年 | 2篇 |
1893年 | 2篇 |
排序方式: 共有1014条查询结果,搜索用时 15 毫秒
71.
72.
Using a global version of the equivariant Chern character, wedescribe the complexified twisted equivariant K-theory of aspace with a compact Lie group action in terms of fixed-pointdata. We apply this to the case of a compact group acting onitself by conjugation and relate the result to the Verlindealgebra and to the Kac numerator at q=1. Verlinde's formulais also discussed in this context. Received February 28, 2007. 相似文献
73.
Corina Fetecau M. Jamil Constantin Fetecau I. Siddique 《International Journal of Non》2009,44(10):854-1090
New exact solutions corresponding to the second problem of Stokes for Maxwell fluids have been established by means of Laplace transforms. For large times, these solutions reduce to the well-known steady-state solutions which are periodic in time and independent of the initial conditions. Furthermore, the transient solutions are in accordance with the previous solutions obtained using the Fourier sine transform. The required time to get the steady-state is determined by graphical illustrations. This time decreases if the frequency of the velocity increases. The effects of the material parameters on the decay of the transients in time are also investigated by graphs. 相似文献
74.
Georgios D. Samaras Nikolaos F. Matsatsinis Constantin Zopounidis 《European Journal of Operational Research》2008
The paper describes a multicriteria decision support system which aims at presenting an evaluation of the Athens Stock Exchange (ASE) stocks, on the basis of fundamental analysis. The system evaluates the stocks based on the method of fundamental analysis ratios, which is the most appropriate evaluation approach regarding investment decisions within a long term horizon. In addition to quantitative data deriving from fundamental analysis, the system uses qualitative data as well, in order to improve the reliability of the evaluation. The system introduced in this paper, utilises multicriteria analysis methodologies in order to rank the stocks by placing the best stock first and the worst last. Stock evaluation considers the specific characteristics of the potential investor, as well as his attitude towards undertaken risk. The final output of the system is four stock rankings which respond to four different criteria groups, depending on the type of accounting plan each listed company belongs to. The system incorporates a large volume of relevant information and operates in ‘real world conditions’ since its data are constantly updated. Finally, the system is intended for both institutional and private investors. 相似文献
75.
76.
Aurelian Luca Maria Sahagia Andrei Antohe Mihail-Răzvan Ioan Leonardo Şerbina Constantin Ivan 《Journal of Radioanalytical and Nuclear Chemistry》2017,311(2):1075-1079
In order to validate its original method for the radon gas activity standardization and to assure the international metrological traceability and equivalence, the Radionuclide Metrology Laboratory of IFIN-HH participated recently in the international comparison CCRI(II)-K2.Rn-222, organized by the International Committee for Weights and Measures—CIPM-CCRI(II)-Radionuclide Measurements. The radon gas sample received, the measurement equipment and the experimental procedures are described. Because the comparison is underway, the results are presented only as relative values to the liquid scintillator vial measurement result. The uncertainty budget of the measurements performed is provided. 相似文献
77.
78.
Holschumacher D Bannenberg T Ibrom K Daniliuc CG Jones PG Tamm M 《Dalton transactions (Cambridge, England : 2003)》2010,39(44):10590-10592
Frustrated carbene-borane Lewis pairs are able to affect the selective cleavage of one of the six P-P bonds in white phosphorus (P(4)) to afford an adduct, in which an abnormal carbene of the imidazolium-4-yl type and B(C(6)F(5))(3) are bound in a trans,trans fashion to a butterfly-like bicyclo[1.1.0]tetraphosphabutane moiety. 相似文献
79.
Constantin JG Fris AR Appignanesi G Carignano M Szleifer I Corti H 《The European physical journal. E, Soft matter》2011,34(11):126
The structure of water clusters (H2O)n (n = 40 -200) and bulk water were examined by molecular dynamics simulations using the TIP4P-ice water model. The analysis of
the low-temperature structures in terms of the local structure index (LSI) showed a bimodal distribution. This finding supports
the two-state picture derived from the analysis of the inherent dynamics of bulk SPC/E water. The water molecules at the outer
interface of the coldest clusters are more structured than those in the inner core. The geometrical constraint of the interface
forces the surface molecules to lose one neighbor and adopt a local angular distribution of hydrogen bonds resembling that
found in the basal plane of ice Ih. 相似文献
80.