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61.
Hongfang Yang Dr. Li Han Jing Zhao Prof. Dr. Xinyu Song Prof. Dr. Qisheng Song Prof. Dr. Yuxiang Bu 《Chemphyschem》2012,13(18):4148-4154
Graphene oxide has attracted intense research interest recently because the graphene oxide synthesis route, as a promising alternative for cost‐effective mass production of graphene, has been explored. To further study the oxidation process and possible mechanism and to explore applicability of the oxidized products, we have performed a computational study on three series of oligoacene dioxides, focusing on their structures and electronic properties. Taking 1,5‐dioxidized naphthalene as a starting point, three series of oligoacene dioxides are considered as follows: 1) middle insertion by 1–2 benzene rings; 2) single‐side expansion using 1–2 benzene rings; 3) double‐side expansion using two benzene rings. On the basis of density functional theory and complete active space self‐consistent field (CASSCF) calculations, we reveal that oligoacene dioxides in the middle insertion series have a triplet ground state, whereas those in the single‐side expansion series and the double‐side expansion series have open‐shell broken‐symmetry singlet diradical ground states except for their common origin naphthalene‐1,5‐dioxide whose ground state is triplet and which is also viewed as the origin of the middle insertion series. Magnetic coupling interactions of these oligoacene dioxides are also determined. This work should help people toward an atomistic understanding of the electronic structures and properties of possible intermediates or products and even the oxidation mechanism of graphene sheets, and provides a reasonable strategy of designing novel graphene‐oxide‐based magnetic materials. 相似文献
62.
Jiqing Xu Renzhang Wang Chunxiao Guo Guoyu Yang Qingxin Zeng Weiming Bu Ling Ye Yuguo Fan Guangdi Yang 《中国科学B辑(英文版)》2001,44(2):137-146
A nickel-1,10-phenanthroline complex supported on an octamolybdate, [(Ni(phen)2
2(ξ-Mo8O26)], has been hydrothermally synthesized with MoO3, H2MoO4, Ni(OAc)2 6H3O and 1,10-phenathroline (1,10-phen) as raw materials. The crystals of the compound belong to monoclinic P21/n space group,a = 1.2952(2),b = 1.6659(10),c = 1.3956(12) nm, β =106.273(8)°,V = 2.8906(5) nm3,Z = 2. 5604 observable reflections (I >2σ(I)) were used for structure resolution and refinements to converge to finalR
1 = 0.0414,wR
2 = 0.0815. The result of structure determination shows that the compound contains octamolybdate possessing a novel structure
type (named as ξ-isomer). The feature of ξ-[Mo8O26]4- is that it is composed of Mo6O6 ring and two MoO6 octahedral located at cap positions on opposite faces. The Mo6O6 ring contains two octahedral and four trigonal-bipyramidal MoVI atoms. Each ξ-[Mo8O26]4- unit is bonded with two [Ni(phen)2]2+ through terminal oxygen atoms of octahedral and neighbouring trigonal-bipyramidal Mo atom in the Mo6O6 ring. IR and UV-Vis spectra of the compound were measured and its electronic structure was studied by EHMO method. 相似文献
63.
Yongjin Fang Bu Yuan Guan Deyan Luan Xiong Wen Lou 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(23):7821-7825
Metal sulfides have received considerable attention for efficient sodium storage owing to their high capacity and decent redox reversibility. However, the poor rate capability and fast capacity decay greatly hinder their practical application in sodium‐ion batteries. Herein, an elegant multi‐step templating strategy has been developed to rationally synthesize hierarchical double‐shelled nanoboxes with the CoS2 nanosheet‐constructed outer shell supported on the CuS inner shell. Their structure and composition enable these hierarchical CuS@CoS2 nanoboxes to show boosted electrochemical properties with high capacity, outstanding rate capability, and long cycle life. 相似文献
64.
Ya‐Pan Wu Jun‐Wu Tian Shan Liu Bo Li Jun Zhao Lu‐Fang Ma Dong‐Sheng Li Ya‐Qian Lan Xianhui Bu 《Angewandte Chemie (International ed. in English)》2019,58(35):12185-12189
Embedding cubane [M4(OH)4] (M=Ni, Co) clusters within the matrix of metal–organic frameworks (MOFs) is a strategy to develop materials with unprecedented synergistic properties. Herein, a new material type based on the pore‐space partition of the cubic primitive minimal‐surface net (MOF‐14‐type) has been realized. CTGU‐15 made from the [Ni4(OH)4] cluster not only has very high BET surface area (3537 m2 g?1), but also exhibits bi‐microporous features with well‐defined micropores at 0.86 nm and 1.51 nm. Furthermore, CTGU‐15 is stable even under high pH (0.1 m KOH), making it well suited for methanol oxidation in basic medium. The optimal hybrid catalyst KB&CTGU‐15 (1:2) made from ketjen black (KB) and CTGU‐15 exhibits an outstanding performance with a high mass specific peak current of 527 mA mg?1 and excellent peak current density (29.8 mA cm?2) at low potential (0.6 V). The isostructural cobalt structure (CTGU‐16) has also been synthesized, further expanding the application potential of this material type. 相似文献
65.
66.
The tittle compounds have directly been synthesized by one-step reaction of two different aldehydes in the presence of ammonia in good to excellent yields. 相似文献
67.
Lukáš Bučinský Stanislav Biskupič Dylan Jayatilaka 《Theoretical chemistry accounts》2011,129(2):181-197
The 2nd order Douglas-Kroll-Hess (DKH2) and the Infinite Order Two Component (IOTC) radial distributions of electron density
of canonical Hartree-Fock (HF) orbitals of radon atom are presented. Furthermore, the total electron density is revisited.
The picture change error (PCE) correction is investigated by analytical means. The point charge model of nucleus and the Gaussian
nucleus model are employed. The basis set is extrapolated by means of including tight s and also p Gaussians within the original triple zeta basis set. It is found that the DKH1 PCE corrected DKH2 total electron and s orbital contact densities are negative for the point charge model of nucleus if tight enough s Gaussians are included in the basis set. It is shown that this failure is caused due to the missing terms of the second order
Douglas-Kroll transformation for the DKH2 electron density. PCE is found the most striking in the DKH2/IOTC electron density
of s orbitals close to the nucleus. The radial distributions of the 2-component p
1/2 orbital densities are considerably affected by PCE at the nucleus as well. Furthermore, the PCE corrected DKH2/IOTC scalar
p orbital densities have a non-zero value of electron density at nucleus and can be considered as an spin-orbit (SO) average
of the p
1/2 and p
3/2 orbitals. The d and f orbitals are affected by PCE in the vicinity of the nucleus only little. The PCE corrected DKH2 and IOTC radial distributions
of orbital densities are nodeless, which is completely in agreement with the radial distribution of the analytic or numeric
DCH orbital densities. 相似文献
68.
Laibin Zhang Huifang Li Jilai Li Xiaohua Chen Yuxiang Bu 《Journal of computational chemistry》2010,31(4):825-836
A comprehensive theoretical study of electronic transitions of naphtho‐homologated base analogs, namely, yy‐T , yy‐C , yy‐A , and yy‐G , was performed. The nature of the low‐lying excited states is discussed, and the results are compared with those from experiment and also with those of y‐bases. Geometrical characteristics of the lowest excited singlet ππ* and nπ* states were explored using the CIS method, and the effects of methanol solution and paring with their complementary natural bases on the relevant absorption and emission spectra of these modified bases were examined. The calculated excitation and emission energies agree well with the measured data, where experimental results are available. In methanol solution, the fluorescence from yy‐A and yy‐G would be expected to occur around 539 and 562 nm, respectively, suggesting that yy‐A is a green‐colored fluorophore, whereas yy‐G is a yellow‐colored fluorophore. The methanol solution was found to red‐shift both the absorption and emission maxima of yy‐A , yy‐T , and yy‐C , but blue‐shift those for yy‐G . Generally, though base pairing has no significant effects on the absorption and fluorescence maxima of yy‐A , yy‐C , and yy‐T , it blue‐shifts those for yy‐G . © 2009 Wiley Periodicals, Inc. J Comput Chem 2010 相似文献
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