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排序方式: 共有484条查询结果,搜索用时 0 毫秒
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Hisanao Hazama Hirofumi Nagao Ren Suzuki Michisato Toyoda Katsuyoshi Masuda Yasuhide Naito Kunio Awazu 《Rapid communications in mass spectrometry : RCM》2008,22(10):1461-1466
The mass spectra of peptides obtained with different matrices were compared using a matrix-assisted laser desorption/ionization (MALDI) ion source and a multi-turn time-of-flight (TOF) mass spectrometer, MULTUM-IMG, which has been developed at Osaka University. Two types of solid matrices, alpha-cyano-4-hydroxycinnamic acid (CHCA) and 2,5-dihydroxybenzoic acid (DHB), and a liquid matrix made from a mixture of 3-aminoquinoline and CHCA were used. When measuring the peak signal intensity of human angiotensin II [M+H]+ from a fixed sample position, the liquid matrix produced a stable signal over 1000 laser shots, while the signal obtained with CHCA and DHB decayed after about 300 and 100 shots, respectively. Significant differences in the mass resolving power were not observed between the spectra obtained with the three matrices. Signal peak areas were measured as a function of the cycle number in a multi-turn ion trajectory, i.e., the total flight time over a millisecond time scale. For both [M+H]+ of human angiotensin II and bovine insulin, the decay of the signal peak area was the most significant with CHCA, while that measured with DHB was the smallest. The results of the mean initial ion velocity measurements suggested that the extent of metastable decomposition of the analyte ions increased in order of DHB, the liquid matrix, and CHCA, which is consistent with the difference in the decay of the signal peak area as the total flight time increased. 相似文献
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Koji Aoyama Yasunori Kimura Wataru Takahashi Masashi Toyoda 《Nonlinear Analysis: Theory, Methods & Applications》2007
In this paper, to find a common fixed point of a family of nonexpansive mappings, we introduce a Halpern type iterative sequence. Then we prove that such a sequence converges strongly to a common fixed point of nonexpansive mappings. Moreover, we apply our result to the problem of finding a common fixed point of a countable family of nonexpansive mappings and the problem of finding a zero of an accretive operator. 相似文献
447.
Kenji Toyoda Yosuke Nakano Ikutaro Hamada Kyuho Lee Susumu Yanagisawa Yoshitada Morikawa 《Journal of Electron Spectroscopy and Related Phenomena》2009,174(1-3):78
We have studied the interaction of pentacene with a Cu(1 1 1) surface using density functional theory (DFT) within a generalized gradient approximation (GGA) and the van der Waals density functional [vdW-DF, M. Dion, H. Rydberg, E. Schröder, D.C. Langreth, B.I. Lundqvist, Phys. Rev. Lett. 92 (2004) 246401]. The adsorption energy is accurately predicted by vdW-DF, while the equilibrium distances between pentacene and the metal substrate (ZC) are overestimated by both GGA and vdW-DF. The work function changes depend significantly on ZC. The experimental work function change can be successfully reproduced by GGA if the experimentally reported adsorption geometry is used, whereas the magnitude of the work function change is underestimated if calculated adsorption geometries are applied. We examined the IDIS model [H. Vázquez, R. Qszwaldowski, P. Pou, J. Ortega, R. Pérez, F. Flores, A. Kahn, Europhys. Lett. 65 (2004) 802] to compare it with the GGA results. The interface dipoles estimated by the IDIS model fairly agree with the GGA results, provided that the adsorption distance is large. On the other hand, they tend to deviate from the GGA results as the adsorption distance becomes smaller, where back donation from the metal surface to the adsorbate occurs. Our analysis reveals that at experimentally reported metal–organic distance, back donation is significant enough to induce polarization of pentacene molecules perpendicular to the surface, which leads to a reduction of the work function. Thus, at the experimentally reported metal–organic distance, the work function change estimated by a simple IDIS model deviates from that calculated by self-consistent GGA calculations. We also found that at the experimentally reported metal–organic distance, the transferred electrons create weak chemical bonds between pentacene and the Cu(1 1 1) surface, illustrating the reactive nature of pentacene. 相似文献
448.
Katsuya Ichihashi Daisuke Konno Kseniya Yu. Maryunina Katsuya Inoue Kazuhiro Toyoda Shogo Kawaguchi Yoshiki Kubota Yoko Tatewaki Tomoyuki Akutagawa Takayoshi Nakamura Sadafumi Nishihara 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(13):4213-4216
Artificial ion channels are of increasing interest because of potential applications in biomimetics, for example, for realizing selective ion permeability through the transport and/or exchange of selected ions. However, selective ion transport and/or exchange in the crystalline state is rare, and to the best of our knowledge, such a process has not been successfully combined with changes in the physical properties of a material. Herein, by soaking single crystals of Li2([18]crown‐6)3[Ni(dmit)2]2(H2O)4 ( 1 ) in an aqueous solution containing K+, we succeeded in complete ion exchange of the Li+ ions in 1 with K+ ions in the solution, while maintaining the crystalline state of the material. This ion exchange with K+ was selectively conducted even in mixed solutions containing K+ as well as Na+/Li+. Furthermore, remarkable changes in the physical properties of 1 resulted from the ion exchange. Our finding enables not only the realization of selective ion permeability but also the development of highly sensitive biosensors and futuristic ion exchange agents, for example. 相似文献
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Y. Soneda J. Yamashita M. Kodama H. Hatori M. Toyoda M. Inagaki 《Applied Physics A: Materials Science & Processing》2006,82(4):575-578
The specific capacitance of exfoliated carbon fibers (ExCF) which were synthesized from pitch-based carbon fibers showed a
strong dependence with the concentration of sulfuric acid electrolyte and reached 1.4 F/m2 in 18 M H2SO4 solution. Since the capacitance value is quite large compared with the case of conventional activated carbons, faradic reactions
(charge transfer reactions) are the cause of pseudo-capacitance. ExCF, however, gave a featureless cyclic voltammogram in
18 M H2SO4 solution. In the case of exfoliated natural graphite, the intercalation of H2SO4 molecules is evidenced by redox peaks observed in the voltammograms in the same conditions. Therefore, a strong interaction
between the H2SO4 molecules and the ExCF surface might be the reason for the origin of pseudo-capacitance with ExCF in H2SO4 electrolyte.
PACS 81.05.Uw; 82.45.Fk; 82.47.Uv 相似文献