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排序方式: 共有587条查询结果,搜索用时 15 毫秒
71.
72.
73.
The Electronic State of Hydrogen in the α Phase of the Hydrogen‐Storage Material PdH(D)x: Does a Chemical Bond Between Palladium and Hydrogen Exist? 下载免费PDF全文
Shun Dekura Prof. Hirokazu Kobayashi Prof. Ryuichi Ikeda Prof. Mitsuhiko Maesato Haruka Yoshino Prof. Masaaki Ohba Prof. Takayoshi Ishimoto Dr. Shogo Kawaguchi Prof. Yoshiki Kubota Dr. Satoru Yoshioka Prof. Syo Matsumura Prof. Takeharu Sugiyama Prof. Hiroshi Kitagawa 《Angewandte Chemie (International ed. in English)》2018,57(31):9823-9827
The palladium–hydrogen system is one of the most famous hydrogen‐storage systems. Although there has been much research on β‐phase PdH(D)x, we comprehensively investigated the nature of the interaction between Pd and H(D) in α‐phase PdH(D)x (x<0.03 at 303 K), and revealed the existence of Pd?H(D) chemical bond for the first time, by various in situ experimental techniques and first‐principles theoretical calculations. The lattice expansion, magnetic susceptibility, and electrical resistivity all provide evidence. In situ solid‐state 1H and 2H NMR spectroscopy and first‐principles theoretical calculations revealed that a Pd?H(D) chemical bond exists in the α phase, but the bonding character of the Pd?H(D) bond in the α phase is quite different from that in the β phase; the nature of the Pd?H(D) bond in the α phase is a localized covalent bond whereas that in the β phase is a metallic bond. 相似文献
74.
Daniella Bekiranov Takayoshi Ogawa Gustavo Ponce 《Proceedings of the American Mathematical Society》1997,125(10):2907-2919
An interaction equation of the capillary-gravity wave is considered. We show that the Cauchy problem of the coupled Schrödinger-KdV equation,
is locally well-posed for weak initial data . We apply the analogous method for estimating the nonlinear coupling terms developed by Bourgain and refined by Kenig, Ponce, and Vega.
75.
Takayoshi Ogawa Takashi Suzuki 《Transactions of the American Mathematical Society》1998,350(12):4897-4918
We study the asymptotic behavior of solutions to a semilinear elliptic equation associated with the critical nonlinear growth in two dimensions.
where is a unit disk in and denotes a positive parameter. We show that for a radially symmetric solution of (1.1) satisfies
Moreover, by using the Pohozaev identity to the rescaled equation, we show that for any finite energy radially symmetric solutions to (1.1), there is a rescaled asymptotics such as
locally uniformly in . We also show some extensions of the above results for general two dimensional domains.
76.
Shigeyasu Tanaka Yoshio Honda Norifumi Kameshiro Ryuta Iwasaki Nobuhiko Sawaki Takayoshi Tanji Mikio Ichihashi 《Journal of Crystal Growth》2004,260(3-4):360-365
We have investigated the morphology of the high-temperature-grown AlN nucleation layer and its role in the early stage of GaN growth, by means of transmission electron microscopy. The nitride was selectively grown on a 7-degree off-oriented (0 0 1) patterned Si substrate by metalorganic vapor phase epitaxy. AlN was deposited on the inclined unmasked (1 1 1) facet in the form of islands. The size of the islands varied along the slope, which is attributable to the diffusion of the growth species in the vapor phase. The GaN nucleation occurred at the region where rounded AlN islands formed densely. The threading dislocations were observed to generate in the GaN nucleated region. 相似文献
77.
Wang GX Han GF Ye Q Xiong RG Akutagawa T Nakamura T Chan PW Huang SD 《Dalton transactions (Cambridge, England : 2003)》2008,(19):2527-2530
A homochiral rare-earth metal Tb complex that exhibited a very large dielectric anisotropic property with a temperature-independent feature is obtained. Our findings on high-dielectric anisotropy will provide a new impetus in this field of materials science. 相似文献
78.
Abe T Miyakushi S Nagai K Norimatsu T 《Physical chemistry chemical physics : PCCP》2008,10(11):1562-1568
Some types of phthalocyanines (MPc (M = H(2), Cu, or Zn), a p-type semiconductor) were used in combination with 3,4,9,10-perylenetetracarboxyl-bisbenzimidazole (PTCBI, an n-type semiconductor), with which those photoelectrode characteristics in the water phase were investigated in terms of kinetics. Each film of the PTCBI/MPc bilayer functioned as a photoanode, where the photoinduced oxidation of thiol occurs at the MPc/water interface along with the hole conduction through the MPc layer. The holes originate on account of the photophysical events in the p/n interior, involving the charge separation of excitons at the p/n interface. The typical photoelectrochemical characteristic in the PTCBI/MPc photoanodes involved a transient photocurrent occurring in the initial stage under illumination (under potentiostatic conditions): thereafter, it attained a steady state. Moreover, both the initial spiky photocurrents and the steady-state photocurrents exhibited saturation at higher concentrations. An analysis with photoelectrode kinetics was performed by assuming an adsorption step prior to a rate-limiting charge transfer step, where equations were applied to photocurrents based on the Langmuir adsorption equilibrium. The kinetic analyses evidently showed that the photoanodic reactions are kinetically dominated by the charge transfer between MPc and thiol, where the overall kinetics for thiol oxidation decreases in the following order: H(2)Pc > ZnPc > CuPc; that is, it appeared that H(2)Pc acts as the more efficient photofunctional interface capable of oxidation in the water phase when PTCBI was concurrently employed as an electron conductor. Considering that the photocurrent generated is proportional to the surface concentration of thiol (Gamma) at the MPc as well as the intrinsic oxidation rate (cf., ZnPc > H(2)Pc approximately CuPc), the higher efficiency in the output at the H(2)Pc surface was attributed to an exceptionally high Gamma (i.e., from the kinetic analyses, the Gamma value at the H(2)Pc surface was also inferred to be 2-3 times higher than that at the other MPcs). Through the present kinetic analysis, it also revealed that the activity for thiol oxidation taking place at Pc ring is comparable to that at the conventional active catalysts (i.e., polycarboxyphthalocyaninato Co(ii) and Fe(iii)) where a central metal is an active site. 相似文献
79.
Gibbs energies of activation for viscous flow of binary water (1) + dimethyl sulfoxide (2) mixtures, Δμ
12○, and of lysozyme (3) in corresponding ternary mixtures, Δμ
3○, were determined at 298.15 K. The binary mixtures have a maximum in the value of the excess quantity for Δμ
12○ at a dimethyl sulfoxide mole fraction of x
2≈0.31. The values of Δμ
3○ are larger than Δμ
12○ at all values of x
2, even when normalized by their molar volumes, suggesting that the solvents interact more strongly with lysozyme than with
themselves. The values of Δμ
3○ significantly increased in the range of x
2=0.3 to 0.4 because of an increase in solvent-lysozyme interactions, which resulted from an increase in the accessible surface
area of lysozyme that was exposed by its unfolding. The mean value obtained for Δμ
3○ per amino acid of lysozyme at x
2=0.2 is greater than that for hydrophobic amino acids, indicating that the solvent interacts with hydrophilic amino acids
more strongly than with hydrophobic ones. 相似文献
80.
Takahashi T Asami Y Kitamura E Suzuki T Wang X Igarashi J Morohashi A Shinojima Y Kanou H Saito K Takasu T Nagase H Harada Y Kuroda K Watanabe T Kumamoto S Aoyama T Matsumoto Y Bando T Sugiyama H Yoshida-Noro C Fukuda N Hayashi N 《Chemistry & biology》2008,15(8):829-841
Pyrrole-imidazole polyamide (PIP) is a nuclease-resistant novel compound that inhibits gene expression through binding to the minor groove of DNA. Human aurora kinase-A (AURKA) and -B (AURKB) are important regulators in mitosis during the cell cycle. In this study, two specific PIPs (PIP-A and PIP-B) targeting AURKA and AURKB promoter regions were designed and synthesized, and their biological effects were investigated by several in vitro assays. PIP-A and PIP-B significantly inhibited the promoter activities, mRNA expression, and protein levels of AURKA and AURKB, respectively, in a concentration-dependent manner. Moreover, 1:1 combination treatment with both PIPs demonstrated prominent antiproliferative synergy (CI value [ED(50)] = 0.256) to HeLa cells as a result of inducing apoptosis-mediated severe catastrophe of cell-cycle progression. The novel synthesized PIP-A and PIP-B are potent and specific gene-silencing agents for AURKA and AURKB. 相似文献