全文获取类型
收费全文 | 4398篇 |
免费 | 271篇 |
国内免费 | 164篇 |
专业分类
化学 | 2794篇 |
晶体学 | 54篇 |
力学 | 134篇 |
综合类 | 12篇 |
数学 | 801篇 |
物理学 | 1038篇 |
出版年
2023年 | 51篇 |
2022年 | 56篇 |
2021年 | 91篇 |
2020年 | 105篇 |
2019年 | 88篇 |
2018年 | 89篇 |
2017年 | 80篇 |
2016年 | 161篇 |
2015年 | 144篇 |
2014年 | 178篇 |
2013年 | 260篇 |
2012年 | 301篇 |
2011年 | 300篇 |
2010年 | 197篇 |
2009年 | 182篇 |
2008年 | 245篇 |
2007年 | 251篇 |
2006年 | 225篇 |
2005年 | 211篇 |
2004年 | 159篇 |
2003年 | 109篇 |
2002年 | 131篇 |
2001年 | 66篇 |
2000年 | 75篇 |
1999年 | 56篇 |
1998年 | 44篇 |
1997年 | 53篇 |
1996年 | 59篇 |
1995年 | 38篇 |
1994年 | 42篇 |
1993年 | 47篇 |
1992年 | 44篇 |
1991年 | 35篇 |
1990年 | 28篇 |
1989年 | 24篇 |
1988年 | 22篇 |
1987年 | 25篇 |
1986年 | 29篇 |
1985年 | 26篇 |
1984年 | 19篇 |
1983年 | 25篇 |
1982年 | 27篇 |
1981年 | 31篇 |
1980年 | 22篇 |
1979年 | 27篇 |
1978年 | 23篇 |
1977年 | 36篇 |
1976年 | 22篇 |
1975年 | 23篇 |
1974年 | 13篇 |
排序方式: 共有4833条查询结果,搜索用时 93 毫秒
71.
72.
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
73.
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
74.
George V. Eleftheriades Gabriel M. Rebeiz 《International Journal of Infrared and Millimeter Waves》1993,14(10):1925-1946
In this paper, an efficient implementation of the spectral domain moment technique is presented for computing the self and mutual coupling between slot antennas on a dielectric half-space. It is demonstrated that by the proper selection of the weighting functions in the method of moments, the analytic evaluation or simplification of the transverse moment integrals is enabled. This results into a significant reduction of the required computational labor. The method is then utilized in order to provide design data for the self and mutual admittances between two slot antennas on a dielectric substrate lens in the case of fused quartz (
r
=3.80), crystal quartz (
r
=4.53), silicon (
r
=11.9) and GaAs (
r
=12.8). The presented technique and associated results are useful when designing twin slot quasi-optical receivers, imaging arrays, phased arrays or power-combining arrays of slot elements at millimeter-wave frequencies. 相似文献
75.
76.
Gabriel Nagy 《Communications in Mathematical Physics》1993,153(2):217-228
We prove that the Haar state associated to the compact matrix quantum groupSU
(N) is faithful for ]–1,1[,0, and anyN2. 相似文献
77.
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
78.
Morelos A Albuquerque IF Bondar NF Carrigan RA Chen D Cooper PS Lisheng D Denisov AS Dobrovolsky AV Dubbs T Endler AM Escobar CO Foucher M Golovtsov VL Gottschalk H Gouffon P Grachev VT Khanzadeev AV Kubantsev MA Kuropatkin NP Lach J Lang Pengfei Li Chengze Li Yunshan Luksys M Mahon JR McCliment E Newsom C Pommot Maia MC Samsonov VM Schegelsky VA Shi Huanzhang Smith VJ Tang Fukun Terentyev NK Timm S Tkatch II Uvarov LN Vorobyov AA Yan Jie Zhao Wenheng Shuchen Z Zhong Yuanyuan 《Physical review letters》1993,71(21):3417-3420
79.
Morelos A Albuquerque IF Bondar NF Carrigan RA Chen D Cooper PS Dai Lisheng Denisov AS Dobrovolsky AV Dubbs T Endler AM Escobar CO Foucher M Golovtsov VL Gottschalk H Gouffon P Grachev VT Khanzadeev AV Kubantsev MA Kuropatkin NP Lach J Lang Pengfei Li Chengze Li Yunshan Luksys M Mahon JR McCliment E Newsom C Pommot Maia MC Samsonov VM Schegelsky VA Shi Huanzhang Smith VJ Tang Fukun Terentyev NK Timm S Tkatch II Uvarov LN Vorobyov AA Yan Jie Zhao Wenheng Zheng Shuchen Zhong Yuanyuan 《Physical review letters》1993,71(14):2172-2175
80.