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141.
We demonstrate a new method for a real-time imaging of surface acoustic waves at frequencies up to 1 GHz with picosecond temporal and micron spatial resolutions using an ultrafast optical pump and probe technique combined with a common path interferometer. Using samples with isotropic or anisotropic substrates coated with metallic thin films, we observe the propagation of Rayleigh-like modes and surface-skimming bulk modes as well as resolving surface phonon focusing effects. In addition we image surface acoustic wave propagation in a laterally inhomogeneous sample. 相似文献
142.
Y.H. Zhang M. Oshima Y. Toh M. Koizumi A. Osa T. Shizuma T. Hayakawa M. Sugawara H. Kusakari T. Morikawa S.X. Wen L.H. Zhu 《The European Physical Journal A - Hadrons and Nuclei》2002,13(4):429-433
The 109,111,113Rh nuclei have been produced as fission fragments in the fusion reaction 18O + 208Pb at 85 MeV. Their level schemes have been built from gamma-rays detected using the Euroball IV array. High-spin states of
the neutron-rich 111,113Rh nuclei have been identified for the first time. Several rotational bands with the odd proton occupying the πg
9/2, πp
1/2 and π(g
7/2/d
5/2) sub-shells have been observed. A band of low-energy transitions has been identified at excitation energy around 2 MeV in
109,111Rh, which can be interpreted in terms of three-quasiparticle excitation, πg
9/2νh
11/2νg
7/2/d
5/2. In addition another structure built on states located at low excitation energy (608 keV in 111Rh, 570 keV in 113Rh) points out that, as already observed in the lighter isotopes 107,109Rh, triaxial deformation plays a role in the neutron-rich Rh isotopes well beyond the mid-shell.
Received: 15 July 2002 / Accepted: 9 October 2002 / Published online: 3 December 2002
RID="a"
ID="a"e-mail: porquet@csnsm.in2p3.fr
RID="b"
ID="b"Present address: CSNSM IN2P3-CNRS and Université Paris-Sud 91405 Orsay, France.
RID="c"
ID="c"Present address: CEA/Saclay, DSM/DAPNIA/SPhN, 91191 Gif-sur-Yvette Cedex, France.
Communicated by D. Schwalm 相似文献
143.
形变双奇核178Ir转动带能级的旋称反转 总被引:1,自引:0,他引:1
张玉虎 T.Hayakawa M.Oshima Y.Toh J.Katakura Y.Hatsukawa M.Matsuda N.Shinohara T.Ishii H.Kusakari M.Sugawara T.Komatsubara 《中国物理 C》2000,24(12):1123-1130
利用152Sm(31P,5nγ)178Ir反应产生并研究了双奇核178Ir的高自旋态.实验中进行了178Ir核的在束γ测量,包括γ射线的激发函数测量、X–γ和γ–γ符合测量.首次建立了双奇核178Ir基于πh9/2νi13/2和πh11/2νi13/2准粒子组态上的转动带能级纲图.发现在低自旋区,两个转动带能级均出现旋称反转.对此核区半退耦带的旋称反转作了简要的分析和讨论. 相似文献
144.
145.
Asymmetric Total Synthesis of Indole Alkaloids Containing an Indoline Spiroaminal Framework
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Dr. Takeshi Yamada Dr. Tetsuya Ideguchi‐Matsushita Dr. Tomoyasu Hirose Dr. Tatsuya Shirahata Dr. Rei Hokari Dr. Aki Ishiyama Dr. Masato Iwatsuki Dr. Akihiro Sugawara Dr. Yoshinori Kobayashi Dr. Kazuhiko Otoguro Prof. Satoshi Ōmura Prof. Toshiaki Sunazuka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(33):11855-11864
The total synthesis of the indole alkaloids, neoxaline, oxaline and meleagrin A, all containing a unique indoline spiroaminal framework, was accomplished through the stereoselective introduction of a reverse prenyl group to the congested benzylic carbon of furoindoline, a two‐pot transformation of indoline (containing three nitrogen atoms at appropriate positions) to the featured indoline spiroaminal framework, and elimination of carbonate assisted by the adjacent imidazole moiety to construct the (E)‐dehydrohistidine. The absolute stereochemistry of neoxaline was elucidated through our total synthesis. In addition, we evaluated the bioactivity, especially the anti‐infectious properties, of neoxaline and oxaline, and of some synthetic intermediates. 相似文献
146.
Takehiro YoshikawaShuichi Sugawara Toshiyuki Takayanagi Motoyuki ShigaMasanori Tachikawa 《Chemical physics》2012,394(1):46-51
Path-integral molecular dynamics simulations have been performed for porphycene and its isotopic variants in order to understand the effect of isotopic substitution of inner protons on the double proton transfer mechanism. We have used an on-the-fly direct dynamics technique at the semiempirical PM6 level combined with specific reaction parameterization. Our quantum simulations show that double proton transfer of the unsubstituted porphycene at T = 300 K mainly occurs via a so-called concerted mechanism through the D2h second-order saddle point. In addition, we found that both isotopic substitution and temperature significantly affect the double proton transfer mechanism. For example, the contribution of the stepwise mechanism increases with a temperature increase. We have also carried out hypothetical simulations with the porphycene configurations being completely planar. It has been found that out-of-plane vibrational motions significantly decrease the contribution of the concerted proton transfer mechanism. 相似文献
147.
Electronic spectra of hexaamminecobalt(III) complex cation in aqueous solution were analyzed to obtain spectral components. Subsequently, based on the spectral components, the coordination geometry around the cobalt(III) ion was investigated, using the reverse angular overlap model method. The result indicates that the geometry is a trigonally compressed octahedron with the polar angle of 57.9?±?1.0° under D3d symmetry, where the polar angle is the angle between the trigonal axis and the Co–N bond. From this angle, the top and side N–Co–N bond angles are calculated as 94.4° and 85.6°, respectively. The density functional theory computation supported this trigonally compressed structure in aqueous solution. 相似文献
148.
This paper is concerned with the melting of a vertical ice plate into a calcium chloride aqueous solution inside a rectangular
cavity. The initial temperature of the ice plate and the mixture are both −5°C and the initial concentration of the mixture
is 20 wt%. The effect of the liquid height H, the width W, the aspect ratio of the liquid region A (=H/W) and the initial ice plate thickness δ
i
on the transient melting mass per unit melting front area, M, is mainly considered numerically. M keeps a similar value in spite of H varied for A = 1 at early melting stage, however, becomes considerably influenced by H as melting progresses. The ice plate melts influenced by A for H = 20 mm fixed at early melting stage due to the fast development of the stagnant region and M decreases with increasing A (=1∼ 10). A dimensionless correlation of the transient melting mass, the aspect ratio and the melting time was presented
under the restricted condition of H = 20 mm. 相似文献
149.
Yusuke Ishigaki Takumi Hashimoto Kazuma Sugawara Shuichi Suzuki Takanori Suzuki 《Angewandte Chemie (International ed. in English)》2020,59(16):6581-6584
Thermally switchable redox properties have been reported to be due to a change in the spin state of newly designed overcrowded ethylenes, which can adopt closed‐shell folded and open‐shell twisted forms. In this study, tetrathienylanthraquinodimethane derivatives were designed to be in thermal equilibrium between a more stable folded form and less stable but more donating twisted diradical in solution, so that the oxidation potential can be controlled by heating/cooling. This is the first example of a switching of redox properties based on a thermally equilibrated twisted diradical, which can be more readily oxidized to the twisted dication. 相似文献
150.
Naoki Saito Masashi Tachi Ryu-Ichi Seki Yayoi Sugawara Eri Takeuchi Akinori Kubo 《合成通讯》2013,43(13):2407-2421
3-Hydroxy-4-methoxy-5-methylbenzaldehyde derivative (1c) has been synthesized in 7 steps from 2,3-dihydroxytoluene (4). An isopropyl derivative has been used to protect a phenol during this transformation. The overall yield of 1c was 37%. 相似文献