全文获取类型
收费全文 | 1002篇 |
免费 | 23篇 |
国内免费 | 3篇 |
专业分类
化学 | 713篇 |
晶体学 | 4篇 |
力学 | 10篇 |
数学 | 34篇 |
物理学 | 267篇 |
出版年
2022年 | 5篇 |
2021年 | 12篇 |
2020年 | 7篇 |
2019年 | 11篇 |
2018年 | 7篇 |
2017年 | 5篇 |
2016年 | 14篇 |
2015年 | 15篇 |
2014年 | 14篇 |
2013年 | 48篇 |
2012年 | 40篇 |
2011年 | 76篇 |
2010年 | 34篇 |
2009年 | 44篇 |
2008年 | 53篇 |
2007年 | 61篇 |
2006年 | 51篇 |
2005年 | 53篇 |
2004年 | 42篇 |
2003年 | 39篇 |
2002年 | 33篇 |
2001年 | 31篇 |
2000年 | 23篇 |
1999年 | 16篇 |
1998年 | 13篇 |
1997年 | 9篇 |
1996年 | 12篇 |
1995年 | 13篇 |
1994年 | 17篇 |
1993年 | 8篇 |
1992年 | 16篇 |
1991年 | 14篇 |
1990年 | 15篇 |
1989年 | 10篇 |
1988年 | 14篇 |
1987年 | 12篇 |
1986年 | 9篇 |
1985年 | 22篇 |
1984年 | 12篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 14篇 |
1980年 | 11篇 |
1979年 | 14篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1973年 | 8篇 |
1972年 | 3篇 |
1968年 | 2篇 |
排序方式: 共有1028条查询结果,搜索用时 11 毫秒
91.
Takahito Itoh Motoka Ikeda Nobuyuki Hirata Yuji Moriya Zhaoyin Wen Yoshiaki Ichikawa Masataka Kubo Osamu Yamamoto 《Ionics》2002,8(1-2):44-52
Terminal-acetylated hyperbranched poly(ethylene glycol) derivatives containing diethylene, triethylene, and hexaethylene and
3,5-dioxybenzoate branching units (poly-Ac1a, poly-Ac1b, and poly-Ac1c) were synthesized. Electrochemical and thermal properties of the hyperbranched polymer electrolytes with lithium salts such
as LiCF3SO3 and LiN(CF3SO2)2, the composite hyperbranched polymer electrolytes with LiN(CF3SO2)2 containing α-LiAlO2 and γ-LiAlO2 fillers, and the hyperbranched polymer blended poly(ethylene oxide) electrolytes with LiN(CF3SO2)2 were investigated and discussed.
Paper presented at the 8th EuroConference on Ionics, Carvoeire, Algarve, Portugal, Sept. 16–22, 2001. 相似文献
92.
T. Araki J. Kubo E. A. Paschos 《The European Physical Journal C - Particles and Fields》2006,45(2):465-475
We consider leptogenesis in a minimal S3 extension of the standard model with an additional Z2 symmetry in the leptonic sector. It is found that the CP phase appearing in the mass matrix of the left-handed neutrinos is the same as that for the CP asymmetries responsible for leptogenesis. Because of the discrete S3 x Z2 flavor symmetries, the CP asymmetries are strongly suppressed. To obtain a realistic size of the baryon number asymmetry in the universe, we therefore
have to assume that resonant enhancement of the CP asymmetries takes place, and that three degenerate right-handed neutrino masses of O(10) TeV are present.
Arrival of the final proofs: 22 November 2005
PACS:
11.30.Hv, 12.15.Ff, 14.60.Pq 相似文献
93.
Ken Hosoya Hiroshi Aoki Takuya Kubo Masashi Teramachi Nobuo Tanaka Jun Haginaka 《Journal of polymer science. Part A, Polymer chemistry》2005,43(12):2556-2566
Highly crosslinked polymer networks were characterized in terms of structural differences based on the crosslinked network structures with their chromatographic molecular retentivity for some polyaromatic hydrocarbons (PAHs). Because PAHs and some sterically bulky solutes were used in the chromatographic characterization, tiny differences in the crosslinked polymer networks were observed in terms of the chromatographic molecular retentivity. Ethylene dimethacrylate afforded molecular retentivity for anthracene, and this recognition ability changed with the polymerization time. In addition, 1,4‐butanediol dimethacrylate afforded molecular retentivity for pyrene, and this retentivity was larger than that for anthracene. The polymerization methods also affected the resulting polymer networks drastically. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2556–2566, 2005 相似文献
94.
Hideaki Hioki Mizuki Fukutaka Miwa Kubo Mitsuaki Kodama Keiko Ideta 《Tetrahedron》2005,61(45):10643-10651
A new traceless linker was developed to synthesize a library of 42 compounds possessing an azomethine linkage using combinatorial solid-phase parallel synthesis. The loading of the substrates on a solid support and cleavage from the solid support were performed by an imine synthesis and by imine-exchanged process under mild conditions, respectively. Thioesters with a hydroxy group on the central core exhibited liquid crystalline properties with the widest transition temperatures in the library. 相似文献
95.
Atsushi Kubo Thomas P. Spaniol Takehiko Terao 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1998,133(2):330-340
The effect of bulk magnetic susceptibility (BMS) on solid state NMR spectra of paramagnetic compounds was investigated theoretically and experimentally. The BMS shift was calculated for cylindrical and spherocylinderical containers with some ratios of the lengthLand the diameterD. The results show the best resolution can be obtained by using a long cylindrical sample container withL/D> 10 and by exciting only the region near the center of the container. The effect of the random orientations and distributions of crystallites in a powder sample was also calculated according to a model proposed by Schwerket al.[J. Magn. Reson. A119, 157 (1996)] with removing the Fermi contact term from their model. Static and the magic-angle spinning13C NMR spectra were recorded on two paramagnetic compounds of Ln(C2D5SO4)3· 8H2O where Ln = Pr, Yb. The modified theory predicts the BMS broadening of the experimental spectra very well. 相似文献
96.
Kazuhiro Kubo 《Journal of Molecular Spectroscopy》2003,222(2):255-262
Rotational spectra of four rare isotopic species of OCS were observed in the 110-690 GHz region with a source-modulated submillimeter-wave spectrometer. Spectral lines of 18O13CS, O13C36S, 18OC36S, and 18O13C34S were measured in their natural abundances, 21.4, 1.51, 0.29, and 0.95 ppm, respectively. The rotational constants and centrifugal distortion constants were precisely determined from observed line frequencies by least squares methods. In order to facilitate sensitivity examination in the submillimeter-wave region, transition frequencies and peak absorption coefficients were calculated and tabulated for the spectral lines of the four species up to the 1000 GHz region. 相似文献
97.
Polymer electrolytes plasticized with hyperbranched polymer for lithium polymer batteries 总被引:1,自引:0,他引:1
Hyperbranched polymers (HBPs) with different terminal groups and different ethylene oxide (EO) chain lengths were prepared,
and the influence of the HBP structures including molecular weights and molecular weight distribution on the ionic conductivity
and the mechanical property of the composite polymer electrolytes composed of poly (ethylene oxide) (PEO), HBP, BaTiO3 as a ceramic filler, and LiN(CF3SO2)2 as a lithium salt were investigated. It was found that the molecular weights of the HBP do not affect significantly the ionic
conductivity, but the molecular weight distribution might affect it, and also further branching at the terminals of the HBP
led to a decrease in the ionic conductivity. The HBP with longer EO chain length was effective for enhancement of the ionic
conductivity in comparison with the HBP with shorter one. The increase in cross-linkable groups (acryloyl group) at the terminals
of the HBP improved the tensile strength, but caused the ionic conductivity to decrease. Loosely cross-linked composite polymer
electrolyte showed higher ionic conductivity and higher tensile strength than no cross-linked one.
Paper presented at the Patras Conference on Solid State Ionics — Transport Properties, Patras, Greece, Sept. 14 – 18, 2004. 相似文献
98.
T. Ocho S. Kubo M. Ikeda T. Saito Y. Terumichi Y. Hamada S. Tanaka 《Physics letters. A》1980,77(5):318-320
When ohmic heating power is applied during the microwave discharge at the electron cyclotron resonance, the plasma current and density build-up become fast and the loop voltage required to start the tokamak discharge decreases. The micro-wave burst observed in the initial stage is reduced and the burst of hard X-rays, occurring at the quasi-steady stage of discharge in the case of no microwave injection, disappears, suggesting that the production of run-away electrons is suppressed strongly. 相似文献
99.
100.