全文获取类型
收费全文 | 4569篇 |
免费 | 218篇 |
国内免费 | 140篇 |
专业分类
化学 | 3082篇 |
晶体学 | 53篇 |
力学 | 102篇 |
综合类 | 12篇 |
数学 | 628篇 |
物理学 | 1050篇 |
出版年
2023年 | 28篇 |
2022年 | 34篇 |
2021年 | 41篇 |
2020年 | 72篇 |
2019年 | 72篇 |
2018年 | 58篇 |
2017年 | 61篇 |
2016年 | 121篇 |
2015年 | 101篇 |
2014年 | 124篇 |
2013年 | 222篇 |
2012年 | 240篇 |
2011年 | 246篇 |
2010年 | 156篇 |
2009年 | 169篇 |
2008年 | 198篇 |
2007年 | 232篇 |
2006年 | 177篇 |
2005年 | 199篇 |
2004年 | 159篇 |
2003年 | 117篇 |
2002年 | 126篇 |
2001年 | 81篇 |
2000年 | 107篇 |
1999年 | 102篇 |
1998年 | 75篇 |
1997年 | 89篇 |
1996年 | 86篇 |
1995年 | 57篇 |
1994年 | 78篇 |
1993年 | 78篇 |
1992年 | 78篇 |
1991年 | 51篇 |
1990年 | 41篇 |
1989年 | 46篇 |
1988年 | 42篇 |
1987年 | 52篇 |
1986年 | 67篇 |
1985年 | 59篇 |
1984年 | 48篇 |
1983年 | 50篇 |
1982年 | 67篇 |
1981年 | 41篇 |
1980年 | 63篇 |
1979年 | 46篇 |
1978年 | 42篇 |
1977年 | 45篇 |
1976年 | 47篇 |
1975年 | 46篇 |
1974年 | 27篇 |
排序方式: 共有4927条查询结果,搜索用时 46 毫秒
91.
92.
Belz J Cousins RD Diwan MV Eckhause M Ecklund KM Hancock AD Highland VL Hoff C Hoffmann GW Irwin GM Kane JR Kettell SH Klein JR Kuang Y Lang K Martin R May M McDonough J Molzon WR Riley PJ Ritchie JL Schwartz AJ Trandafir A Ware B Welsh RE White SN Witkowski MT Wojcicki SG Worm S 《Physical review letters》1996,76(18):3277-3280
93.
94.
The ligand-field spectrum of [Cr(NH(3))(4)F(2)]AsF(6) has been pressure-tuned up to 100 kbar. The parametrical analysis shows that the absolute values of the two independent tetragonalities of the chromophoric ion both decrease with increasing isotropic pressure so that the molecular ion becomes more isotropic. Moreover, the Cr-N single bonds appear to be more compressible than the Cr-F bonds, for which it is parametrically clear that they have a partial multiple-bond character. While the spectrochemical parameter for F(-), Delta(F), increases with pressure, its two components Delta(sigma)(F) and Delta(pi)(F) decrease. It is confirmed that nephelauxetism increases with pressure. 相似文献
95.
96.
The characterisation and optimisation of an optical immunoassay with label free detection based on Reflectometric Interference Spectroscopy (RIfS) is presented. The immunoprobe is operated in a sequential scheme, where Fab-fragments react with analyte molecules in a first step. In a second step the optical transducer is used to quantify the amount of unoccupied Fab- fragments in the reaction mixture binding to the hapten-modified transducer surface. For optimisation of the test, the Fab-fragment concentration was varied between 2x10(-8) mol/l and 2.5x 10(-9) mol/l. Down to a concentration of 5x10(-9) mol/l a reduction in the limit of detection has been observed. At the lowest concentration investigated no further improvement has been found due to a reduced binding of the analyte and a strong decrease of antibody binding at the transducer surface. This finding could be explained by the thermodynamics of the antigen-antibody reaction and the performance of the optical transducer used. The limit of detection obtained is discussed with respect to thermodynamics, transducer characteristics and immunoprobe test format. 相似文献
97.
Reinhard Honegger 《Letters in Mathematical Physics》1993,27(3):191-203
By means of cocycle techniques in a recent paper, the global dynamics of mean field-boson couplings has been studied. Here, by restricting to the bosonic system the infinite time limit (t ) for very general initial states, one obtains time-asymptotic states on the bosonicC
*-Weyl algebra, in which one partially rediscovers the collective ordering of the infinite mean field lattice. 相似文献
98.
99.
Motivated by the concept of maximum entropy methods in signal and image processing, we introduce and discuss a class of ‘directed diffusion equations’ with suitable boundary conditions. The paradigmatic ‘directed diffusion equation’ is The relative entropy $ Sb[f](t): = - \int_\Omega {f(t,x)} \;\ln \;(f(t,x)/b(x))dx $ is rapidly increasing along solution trajectories of (i). This suggests that solving (i) will yield efficient procedures for entropy maximization. We also discuss the asymptotic behavior of solutions of (i)—this is readily done because (i) has a large family of Ljapunov functionals. 相似文献
100.
Arisaka K Auerbach LB Axelrod S Belz J Biery KA Buchholz P Chapman MD Cousins RD Diwan MV Eckhause M Ginkel JF Guss C Hancock AD Heinson AP Highland VL Hoffmann GW Horvath J Irwin GM Joyce D Kaarsberg T Kane JR Kenney CJ Kettell SH Kinnison WW Knibbe P Konigsberg J Kuang Y Lang K Lee DM Margulies J Mathiazhagan C McFarlane WK McKee RJ Melese P Milner EC Molzon WR Ouimette DA Riley PJ Ritchie JL Rubin P Sanders GH Schwartz AJ Sivertz M Slater WE Urheim J Vulcan WF Wagner DL Welsh RE Whyley RJ 《Physical review letters》1993,71(24):3910-3913