全文获取类型
收费全文 | 208篇 |
免费 | 2篇 |
国内免费 | 2篇 |
专业分类
化学 | 122篇 |
晶体学 | 7篇 |
数学 | 20篇 |
物理学 | 63篇 |
出版年
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2013年 | 8篇 |
2012年 | 6篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 5篇 |
2008年 | 11篇 |
2007年 | 11篇 |
2006年 | 12篇 |
2005年 | 6篇 |
2004年 | 9篇 |
2003年 | 4篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 7篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有212条查询结果,搜索用时 31 毫秒
21.
Kuwamura N Kitano K Hirotsu M Nishioka T Teki Y Santo R Ichimura A Hashimoto H Wright LJ Kinoshita I 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(38):10708-10715
Interchange between the nickel +2 and +3 oxidation states precisely controls the reversible rearrangement of the tris(2-pyridylthio)methanide (tptm) ligand in the organometallic nickel(II) complex [{Ni(μ-Br)-(tptm)}(2)] (2). Oxidation of 2 first gives the corresponding Ni(III) complex [{Ni(μ-Br)(tptm)}(2)][PF(6)](2) (4). However, in solution the tptm ligand in 4 slowly undergoes a rearrangement, in which the N and S atoms of one of the pyridylthiolate arms exchange Ni and C bonding partners, thereby resulting in an "N,S-confused" isomer of tptm in the product, [NiBr(bpttpm)]PF(6) (5; bpttpm= bis(2-pyridylthio)(2-thiopyridinium)-methyl). Reduction of 5 reverses this ligand rearrangement and 2 is reformed quantitatively. The individual steps involved in these unusual ligand rearrangements were investigated by a number of methods, including voltammetric analysis, and a mechanism for this process is proposed. X-ray crystal structure determinations of the key compounds 2, 4 and 5 have been obtained. 相似文献
22.
Highly sensitive photoalignment of liquid crystals (LCs) can be realized by axis-selective triplet energy transfer. Addition of a triplet photosensitizer (phosphorescent donor) into a photocrosslinkable polymer tethering E-cinnamate side chains ensures dramatic enhancement of photosensitivity to generate the optical anisotropy of polymer film and surface-assisted LC photoalignment. Photoirradiation of triplet photosensitizer-doped polymer films with linearly polarized 365 nm light for the selective excitation of triplet sensitizer gives rise to optical anisotropy of cinnamates as a result of axis-selective triplet energy transfer. By analyzing phosphorescence spectra with theoretical Perrin's formula, we find that triplet energy transfer is efficient within a radius of ~0.3 nm from the triplet photosensitizer. Such photoaligned polymer films can be used for the surface-assisted orientation photocontrol of not only calamitic LC, but also discotic LC, even for extremely low exposure energies. The present procedure would be greatly advantageous for high-throughput fabrication of optical devices by photoalignment techniques. 相似文献
23.
Humio Ichimura 《Archiv der Mathematik》2011,96(6):555-563
Let p be an odd prime number, and pn0{p^{n_0}} the highest power of p dividing 2
p−1 − 1. Let Kn=Q(zpn+1){K_n={\bf Q}(\zeta_{p^{n+1}})} and Ln,j=Kn+(z2j+2){L_{n,j}=K_n^+(\zeta_{2^{j+2}})} for j ≥ 0. Let hn*{h_n^*} be the relative class number of K
n
, and h
n,j
the class number of L
n,j
, respectively. Let n be an integer with n ≥ n
0. We prove that if the ratio hn*/hn-1*{h_n^*/h_{n-1}^*} is odd, then h
n,j
/h
n−1,j
is odd for any j ≥ 0. 相似文献
24.
Takuya Matsumoto Tsutomu Ichimura Takashi Yatsui Motonobu Kourogi Toshiharu Saiki Motoichi Ohtsu 《Optical Review》1998,5(6):369-373
We have developed a novel probe with a nanometric metallized protrusion extending through a subwavelength aperture to increase optical near-field excitation and collection efficiencies. The apex diameter of the fabricated metallized protrusion was 35 nm. The Intensity distribution of the optical near-field at the apex of the probe was measured by scanning another probe across the apex, and it was observed that strong optical near-field was generated at the apex of the metallized protrusion. The width of the intensity distribution was 150 nm including instrumental resolution. Probes with spherical and ellipsoidal metallized protrusion were also fabricated, by which enhancement of the optical near-field is expected due to localized plasmon excitation. 相似文献
25.
Hideo Ichimura David Feinstein Richard F Schwartz 《Journal of Mathematical Analysis and Applications》1980,76(1):270-282
Expressions are given for analytical extraction of parameters for polynomial and single relaxation experiments, and an indication is given of the application of the technique to multiple relaxation experiments. Examples are given for the cases of single and double relaxations. Hypothetical reference is made to time domain reflectometry. 相似文献
26.
Time-resolved absorption spectra of hexafluorobenzene vapor have been observed with ArF laser (193 nm) excitation. The initial intermediate is postulated to be due to HFB2(S0) (hot hexafluorobenzene, with internal energy of 639 kj/mol) because the transient spectrum can be simulated as part of the S3(1E1u) ← S0 transition at 3050 K. 相似文献
27.
Coupled channel calculations for (d, p) reactions were performed in which a strong coupling between the d and p channels was assumed. Reactions investigated were 16O(d, p) 17O(2s) and 40Ca(d, p) 41Ca(2p) at Ed =10.5 MeV and the related (d, d) and (p, p) scattering processes. The nonorthogonality of the d- and p-channels were taken into account. The results of these calculations are presented and are compared with the coupled channel calculations neglecting the channel nonorthogonality and also compared with the DWBA and optical model calculations. 相似文献
28.
Surface segregations of Cu and S in a CuNi (50wt%) alloy at elevated temperatures of ~600°C were studied under scanning Auger electron microscope, JAMP-3. Scanning images of S, Cu and Ni Auger signals have revealed that the surface segregations of both Cu and S take place preferentially depending on grains and the contrasts in S and Cu Auger images are complementary. This leads to another confirmation of the previous work, namely, that the surface segregation of Cu is considerably suppressed by the existence of S at the outermost atom layer. 相似文献
29.
J.M. Fontaine O. Lee-Deacon J.P. Duraud S. Ichimura C. Le Gressus 《Surface science》1982,122(1):40-54
The damaging effects of electron beams during the acquisition of electron spectra have long been an obstacle in surface analysis. In order to understand the physico-chemical processes which take place under electron irradiation in an AlO system, we have carried out an experiment in which artifices, such as heating, charging, and gas contamination, were absent. We have observed with Auger Electron Spectra increases of the oxidation extent and the oxygen concentration on an oxygen exposed (111) textured polycrystalline surface under electron irradiation (5 keV, 9 × 10?5 A/cm2). These increases were not observed on a clean surface, and were very feeble on a (100) single crystal surface. The increase of oxygen concentration was independent of residual gas pressure (3 × 10?9 to 6 × 10?10 Torr) and its composition; and therefore cannot be explained by gas contamination during the experimental period (about 70 min). We attribute the increase of oxidation degree to the transition of chemisorbed oxygen atoms into oxide through direct momentum transfer from the incident electrons. We suggest that the increase of oxygen within the irradiated area is due to the surface diffusion of chemisorbed oxygen atoms from outside the irradiated area. These oxygen atoms are excited by the electrons scattered from the vacuum chamber walls and gain energy through Franck-Condon type mechanism. The absence of chemisorbed oxygen atoms on (100) surface explains the near absence of these increases on this surface. 相似文献
30.
A three-dimensional differential system is proposed, in which the motion becomes chaotic at some parameter value. The asymptotic solution is calculated by using Kuzmak's method. 相似文献