全文获取类型
收费全文 | 918篇 |
免费 | 32篇 |
国内免费 | 4篇 |
专业分类
化学 | 683篇 |
晶体学 | 8篇 |
力学 | 15篇 |
数学 | 66篇 |
物理学 | 182篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 7篇 |
2020年 | 2篇 |
2019年 | 12篇 |
2018年 | 7篇 |
2017年 | 4篇 |
2016年 | 25篇 |
2015年 | 17篇 |
2014年 | 25篇 |
2013年 | 43篇 |
2012年 | 56篇 |
2011年 | 71篇 |
2010年 | 34篇 |
2009年 | 42篇 |
2008年 | 80篇 |
2007年 | 73篇 |
2006年 | 44篇 |
2005年 | 45篇 |
2004年 | 46篇 |
2003年 | 56篇 |
2002年 | 56篇 |
2001年 | 19篇 |
2000年 | 23篇 |
1999年 | 14篇 |
1998年 | 10篇 |
1997年 | 11篇 |
1996年 | 12篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 14篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 9篇 |
1975年 | 8篇 |
1974年 | 4篇 |
1973年 | 6篇 |
1969年 | 2篇 |
排序方式: 共有954条查询结果,搜索用时 46 毫秒
81.
Hirokazu Fukidome Kei Tanaka Kazuyuki Ueda Toyohiko Kinoshita 《Surface science》2007,601(20):4675-4679
The ultrathin oxidation of a H/Si(1 0 0) surface with microfabricated pn-junctions was studied by photoemission electron microscopy (PEEM), mirror electron microscopy (MEM) and microscopic X-ray photoelectron spectroscopy (μ-XPS). The ultrathin oxidation inverts the contrast of the junctions in PEEM images. It is found by analyzing the intensity profiles of images that the potential distribution across the pn-junctions is also inverted by the oxidation. The charging of the oxide by ultraviolet irradiation from a light source of PEEM is attributed as the cause of the inversion of the contrast shown by μ-XPS and MEM. 相似文献
82.
Kuniharu Fujii Satoshi Kera Mika Oiwa Koji K. Okudaira Kazuyuki Sakamoto Nobuo Ueno 《Surface science》2007,601(18):3765-3768
We have investigated the relation between the intramolecular vibrational modes of pentacene and the charge redistribution at the pentacene-graphite interface by using high-resolution electron-energy-loss-spectroscopy. The three main vibrational peaks shift to lower energies as the pentacene film thickness decreases. In order to discuss this energy shift, we have calculated the vibrational energies of a free pentacene molecule by changing its charge state. We have also calculated the vibrational energies of a pentacene molecule adsorbed on a graphite sheet by changing the pentacene-graphite distance. Taking the experimental and calculation results into account, we conclude that the observed energy shifts result from an intramolecular charge redistribution. The present results indicate that the effect of an intramolecular charge redistribution is essential to discuss the origin of an energy shift observed in a vibrational study of an organic molecule/substrate interface. 相似文献
83.
Tooru Kitagawa Kohji Tashiro Kazuyuki Yabuki 《Journal of Polymer Science.Polymer Physics》2002,40(13):1281-1287
Fourier transform Raman spectra were measured for poly‐p‐phenylenebenzobisoxazole (PBO) fiber subjected to a tensile stress, and the Raman shift factor (the frequency shift caused by 1 GPa tensile stress) depended strongly on the sample‐preparation condition. To clarify the reasons of this dependency, a mechanical series parallel model was adopted that could successfully and quantitatively explain the observed Raman shift factors and gave a concreate heterogeneous stress distribution in the PBO fibers. As a result, a mechanical series model was reasonable for PBO fiber. Broadening of Raman bands, which was observed when the PBO fiber was tensioned, could also be interpreted on the basis of an idea of heterogeneous stress distribution. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1281–1287, 2002 相似文献
84.
Yoshito Hirata Shunsuke Horai Kazuyuki Aihara 《The European physical journal. Special topics》2008,164(1):13-22
We propose a method to reproduce distance matrices and original time series
from recurrence plots. The procedure is to (i)convert a recurrence plot
to a weighted graph and (ii)calculate a distance between each pair
of nodes on this weighted graph.
We demonstrate this method by reproducing the topological shape of
original time series.
We also propose two applications.
The first application is to obtain the maximal Lyapunov exponent
from a recurrence plot without reproducing the shapes
of original time series.
The second application is to reconstruct a common deterministic driving
force from observations of forced systems.
Thus, the method opens new fields in data analysis. 相似文献
85.
86.
We discuss the universal version of the Schwinger terms of current algebra (we call it the universal Schwinger cocycle) forp=3 (herep denotes the class of the Schatten idealI
p
, which is related to the (D+1) space-time dimensions byp=(D+1)/2) in detail, and give a conjecture of the general form of the cocycle for anyp. We also discuss the infinite charge renormalizations, the highest weight vector and state vectors forp=3. Last, we give brief comments on the problems caused by the difficulties to construct the measure of infinite-dimensional Grassmann manifolds. 相似文献
87.
Takashi Yoshida Rong Lu Shuqin Han Kazuyuki Hattori Takahiro Katsuta Kei‐Ichi Takeda Kazutoshi Sugimoto Masamitsu Funaoka 《Journal of polymer science. Part A, Polymer chemistry》2009,47(3):824-832
For the synthesis of a new biologically functional polymer from a natural resource by an environment‐friendly method, the laccase‐catalyzed polymerization of a lignin‐based macromonomer, lignocatechol, was carried out for the first time in ethanol–phosphate buffer solvent system to give crosslinked polymers in good yields. Lignocatechol was prepared by the phase separation system of lignin and catechol in aqueous sulfuric acid. The copolymerization was also performed with urushiol to afford the corresponding copolymers in high yields. The polymerization mechanism was estimated by the IR and pyrolysis GC‐MS measurements, suggesting that the polymerization proceeded mainly at the catechol ring through a quinone radical intermediate. The thermal properties were measured by the DSC, TG, and TMA analyses, indicating that the polymers had high thermal stabilities because of the crosslinked structures. In addition, it was found that the resulting polymers had the affinity of bovine serum albumin (BSA) and glucoamylase. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 824–832, 2009 相似文献
88.
Kazuyuki Moriwaki 《Tetrahedron》2010,66(36):7316-7321
Novel methanofullerenes 3 having ethylthienyl and/or n-pentyl groups were designed and synthesized for the purpose of developing new acceptors for an organic photovoltaic cell with higher performance than that of the [6,6]-phenyl-C61-butylic acid methyl ester (PCBM) used as the standard acceptor. The electronic absorption spectra and cyclic voltammetry (CV) of 3, PCBM, and [6,6]-(thiophene-2-yl)-C61-butylic acid methyl ester (ThCBM) were measured to estimate solubility and reduction potentials as characteristics of n-type semiconductor for organic photovoltaic devices. The CV measurements revealed reversible reduction waves for all of the methanofullerenes and the first reduction potentials of the n-pentyl-substituted 1-(5-ethylthiophene-2-yl)-[6,6]-methanofullerene[60] (3b) and 1-phenyl-[6,6]-methanofullerene[60] (3c) were negatively shifted compared to those of the corresponding terminal methyl ester-substituted homologues (3a and PCBM). The performances of photovoltaic devices consisting of 3b and 3c were slightly higher than those of PCBM. 相似文献
89.
90.
Atsuo Yamada Kazuyuki Saka Makiko Uehara Sou Taminato Ryoji Kanno Fabrice Mauvy Claude Grenier 《Electrochemistry communications》2010,12(12):1690-1693
Electrode–electrolyte hetero-epitaxial systems for solid oxide fuel cells (SOFCs) with two different configuration of Nd2NiO4 + δ(110)//YSZ(100) and Nd2NiO4 + δ(100)//YSZ(110) were successfully fabricated by pulsed laser deposition. Thin films of Nd2NiO4 + δ approximately 20 nm thick were grown on a commercial single crystal of YSZ. The preferred two-dimensional diffusion paths of the oxide ions were perpendicular to the substrate for both configurations and showed oxygen reduction capability different from each other. This opens up new research direction focusing on the details of anisotropic catalytic activity of SOFC cathode depending on the crystalline surface. 相似文献