全文获取类型
收费全文 | 10286篇 |
免费 | 1919篇 |
国内免费 | 1567篇 |
专业分类
化学 | 8089篇 |
晶体学 | 144篇 |
力学 | 632篇 |
综合类 | 94篇 |
数学 | 1388篇 |
物理学 | 3425篇 |
出版年
2024年 | 18篇 |
2023年 | 159篇 |
2022年 | 311篇 |
2021年 | 344篇 |
2020年 | 383篇 |
2019年 | 436篇 |
2018年 | 358篇 |
2017年 | 316篇 |
2016年 | 528篇 |
2015年 | 605篇 |
2014年 | 618篇 |
2013年 | 775篇 |
2012年 | 911篇 |
2011年 | 914篇 |
2010年 | 734篇 |
2009年 | 692篇 |
2008年 | 729篇 |
2007年 | 586篇 |
2006年 | 527篇 |
2005年 | 495篇 |
2004年 | 448篇 |
2003年 | 410篇 |
2002年 | 516篇 |
2001年 | 423篇 |
2000年 | 267篇 |
1999年 | 225篇 |
1998年 | 193篇 |
1997年 | 134篇 |
1996年 | 120篇 |
1995年 | 112篇 |
1994年 | 89篇 |
1993年 | 71篇 |
1992年 | 58篇 |
1991年 | 60篇 |
1990年 | 39篇 |
1989年 | 28篇 |
1988年 | 21篇 |
1987年 | 18篇 |
1986年 | 10篇 |
1985年 | 8篇 |
1984年 | 15篇 |
1983年 | 11篇 |
1982年 | 4篇 |
1981年 | 13篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1976年 | 3篇 |
1974年 | 5篇 |
1936年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Analytic solutions of an iterative functional equation 总被引:4,自引:0,他引:4
63.
64.
Two homologous series of mesogenic materials which incorporate a 1,4-tetrafluorophenylene moiety and a terminal cyano- or nitro-substituent have been synthesized by using palladiumcatalysed coupling procedures. The compounds exhibit nematic and/or smectic A phases. 相似文献
65.
Y. H. Zhang X. H. Zhou Q. Z. Zhao X. F. Sun X. G. Lei Y. X. Guo Z. Liu X. F. Chen Y. T. Zhu S. X. Wen G. J. Yuan X. A. Liu 《Zeitschrift für Physik A Hadrons and Nuclei》1996,355(1):335-336
High spin states of the odd-odd162Lu nucleus have been studied via147Sm(19F,4nγ)162Lu reaction at 95 MeV beam energy. Level scheme for yrast band based onπ[h11/2 v[i13/2] quasiparticle configuration was established up to I π = (23?) for the first time. This band shows the signature inversion in energy before backbending generally appeared in this mass region. It is stressed that the signature splitting in162Lu is larger than that in the160Tm nucleus. 相似文献
66.
Based on the anisotropic Seebeck tensor coefficients, a light-thermo-radiation detector made of high-Tc superconductor (YBa2Cu3O7-δ) was fabricated, which can function at room temperature. The induced voltaic signals at various modulation frequencies for radiation from He-Ne laser and from a 500 K black body were measured. The noise ratio for detecting He-Ne laser radiation and the D* for black body were evaluated. Compared with bolometer made of high-Tc superconductor which functions at liquid nitrogen, and with pyroelectric detector, it was found that the advantages of this new device are that the device can work at room temperature with very low noise and very fast response. Although having a lower D* value than that of bolometer for the present device construction, we point out the possibility and the direction for improving the D* value, hence the promising prospect of this kind of device. 相似文献
67.
Hua Ning LIU Wen Peng ZHANG 《数学学报(英文版)》2007,23(5):915-924
The main purpose of this paper is to use the generalized Bernoulli numbers, Gauss sums and the mean value theorems of Dirichlet L-functions between a quadratic residue and its inverse modulo p value formula. to study the asymptotic property of the difference (a prime), and to give an interesting hybrid mean 相似文献
68.
Three novel zinc complexes [Zn(dbsf)(H2O)2] ( 1 ), [Zn(dbsf)(2,2′‐bpy)(H2O)]·(i‐C3H7OH) ( 2 ) and [Zn(dbsf)(DMF)] ( 3 ) (H2dbsf = 4,4′‐dicarboxybiphenyl sulfone, 2,2′‐bpy = 2,2′‐bipyridine, i‐C3H7OH = iso‐propanol, DMF = N,N‐dimethylformamide) were first obtained and characterized by single crystal X‐ray crystallography. Although the results show that all the complexes 1–3 have one‐dimensional chains formed via coordination bonds, unique three‐dimensional supramolecular structures are formed due to different coordination modes and configuration of the dbsf2? ligand, hydrogen bonds and π–π interactions. Iso‐propanol molecules are in open channels of 2 while larger empty channels are formed in 3 . As compared with emission band of the free H2dbsf ligand, emission peaks of the complexes 1–3 are red‐shifted, and they show blue emission, which originates from enlarging conjugation upon coordination. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
69.