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701.
Sergey Larin Sergey Lyulin Alexey Lyulin Anatoly Darinskii 《Macromolecular Symposia》2009,278(1):40-47
Complexes formed by star-like polymers of various topology and oppositely charged linear polyelectrolytes were simulated using Brownian dynamics technique. Structural properties and their dependence on the polyelectrotyte charge were investigated and compared with similar data for complexes with dendrimers. Remarkable overcharging was observed for all stars in complexes. 相似文献
702.
A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL. 相似文献
703.
Gromov Oleg I. Feklichev Evgeny D. Zhidomirov Georgy M. Rybaltovskii Alexey O. Sviridov Alexander P. Grigoriev Yuriy V. Ischenko Anatoly A. Bagratashvili Victor N. Golubeva Elena N. 《Journal of nanoparticle research》2019,21(6):1-10
Journal of Nanoparticle Research - One-dimensional silver telluride nanowires (NWs) as potential thermoelectric materials have been studied extensively. At present, most of the efforts are focused... 相似文献
704.
We report the observation of the rotationally resolved spectrum of the c1A1 state of CH2 via sequential single-photon absorptions at visible and near-infrared wavelengths. Direct absorption from the lowest singlet state a1A1 to c1A1 occurs in the near UV, but it is weak because it corresponds to a two electron transition between the dominant single configuration approximations to the electronic wave functions. Some absorption lines in the c-a system were originally reported in 1966 [G. Herzberg and J. W. C. Johns, Proc. R. Soc. London, Ser. A 295, 107 (1966)], but the weak spectra could not be assigned at the time. Interest in the c1A(1) state was rekindled by recent ab initio results [S. N. Yurchenko, P. Jensen, Y. Li, R. J. Buenker, and P. R. Bunker, J. Mol. Spectrosc. 208, 136 (2001)] which prompted the present work. The new spectra provide accurate energies for rotational levels in the v2linear =11,l = 1 level of the state, and permit assignment of most of the line positions measured by Herzberg and Johns. The double-resonance technique used may be easily extended to the measurement of lower rovibrational levels in the electronic state and possibly also to access the d1A2 state which is theoretically expected to lie at similar energies but, for symmetry reasons, is not accessible from the lowest singlet state in a single electric-dipole transition. 相似文献
705.
706.
707.
A new quantitative measure of molecular dissymmetry is proposed that is based on quantum-mechanical counterparts of notions extracted from differential geometry. Starting with the so-called torsion of a curve, we arrive at a chirality operator and appropriate average as the chirality index æ. The essential properties of æ are its additivity and also its ability to vanish for the racemic mixture of chiral structures. Some quantum-chemical approaches to calculating æ are presented, e.g., a typical one using only the adjacency matrix and the coordinates of atoms. Quasi-continuous and continuous systems, such as helices and Möbius-like structures, are studied. 相似文献
708.
709.
Two sorts of bosons in an optical lattice at commensurate filling factors can form five stable super-fluid and insulating ground states with rich and nontrivial phase diagram. The structure of the ground state diagram is established by mapping a d-dimensional quantum system onto a (d+1)-dimensional classical loop-current model and Monte Carlo (MC) simulations of the latter. Surprisingly, the quantum phase diagram features, besides second-order lines, first-order transitions and two multicritical points. We explain why first-order transitions are generic for models with pairing interactions using microscopic and mean-field (MF) arguments. In some cases, the MC results strongly deviate from the MF predictions. 相似文献
710.
We study superfluid-solid zero-temperature transitions in two-dimensional lattice boson-spin models using worm-algorithm Monte Carlo simulations. We observe that such transitions are typically first order with the exception of special high-symmetry points which require fine-tuning in the Hamiltonian parameter space. We present evidence that the superfluid-checkerboard solid and superfluid-valence-bond solid transitions at half-integer filling factor are extremely weak first-order transitions and in small systems can be confused with continuous or high-symmetry points. 相似文献