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101.
Ionic liquids (ILs) are salts with an extremely low melting point. Substantial efforts have been made to address their low melting point from the enthalpic standpoint (i.e. interionic interactions). However, this question is still open. In this study, we report our findings that entropic (large fusion entropy), rather than enthalpic, contributions are primarily responsible for lowering the melting point in many cases, based on a large thermodynamic dataset. We have established a computational protocol using molecular dynamics simulations to decompose fusion entropy into kinetic (translational, rotational, and intramolecular vibrational) and structural (conformational and configurational) terms and successfully applied this approach for two representatives of ILs and NaCl. It is revealed that large structural contribution, particularly configurational entropy in the liquid state, plays a deterministic role in the large fusion entropy and consequently the low melting point of the ILs.Large structural entropy makes salts liquid at room temperature. 相似文献
102.
Yoshifumi Karakawa Kazuhiko Oka Hitoshi Odashima Kojiro Takagi Shozo Tsunekawa 《Journal of Molecular Spectroscopy》2001,210(2)
The rotational spectrum of methyl formate (HCOOCH3) has been observed in the frequency range from 7 to 200 GHz. We newly assigned 1612 lines in the ground torsional state and simultaneously analyzed both A- and E-species data including previously reported lines on the basis of the internal axis method. A total of 3077 lines were fitted to a 1σ standard deviation of 139 kHz, and molecular parameters were determined. 相似文献
103.
Nobuo Yamada Dr. Hiroki Noguchi Yoshifumi Orimoto Dr. Yutaka Kuwahara Prof. Dr. Makoto Takafuji Shaheen Pathan Dr. Reiko Oda Almara Mahammadali Rahimli Prof. Dr. Mahammadali Ahmed Ramazanov Prof. Dr. Hirotaka Ihara 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(43):10141-10148
In this work, a new class of totally organic fluorescent nanogel particles and their exceptionally specific behaviors based on their unique structures are introduced, which draws a sharp line from conventional fluorophore-doped and fluorophore-branched-type particles. The nanogel particles, the diameter of which could be controlled by adjusting reaction conditions, such as the solvent system, were spontaneously fabricated with a spherical shape by direct polymerization of non-heterocyclic aromatic compounds, such as 2,6-dihydroxyanthracene, 2,6-dihydroxynaphthalene, and 9,9-bis(4-hydroxyphenyl)fluorene with triazinane as the cross-linker. A fluorophoric moiety formed from a polymer main chain was realized in the particle, and consequently, the resultant content of the fluorophoric moiety was around 70–80 wt % per particle. The uniqueness and versatility of the particles can be emphasized by their good compatibility with various solvents due to their amphiphilic and ampholytic swelling properties, but also by their remarkable fluorescent solvatochromism in the dispersion state. Furthermore, these behaviors were preserved even in their polymer composite system. This study also demonstrates that various fluorescent polymer films can be fabricated with emission color control due to memorization of the solvatochromism phenomenon of the dispersed fluorescent nanoparticles. 相似文献
104.
105.
Shoichi Ichinose 《Letters in Mathematical Physics》1986,11(2):113-120
The gauge fixing problem in the conformal (spinor and scalar) QED is examined. For the analysis, we generalize Dirac's manifestly conformal-covariant formalism. It is shown that the (vector and matter) fields must obey a certain mixed (conformal and gauge) type of transformation law in order to fix the local gauge symmetry preserving the conformal invariance in the Lagrangian. 相似文献
106.
Wataru Ichinose 《Communications in Mathematical Physics》1997,189(1):17-33
We study the formulation of the Feynman path integral through broken line paths in non-relativistic quantum mechanics. This
formulation is very familiar to us and well known to be useful. But its rigorous meaning is given little except for special
cases. In the present paper, using the ideas in the theory of difference methods and the theory of pseudo-differential operators,
we show rigorously for some class of potentials that this formulation is well defined and that this Feynman path integral
gives the probability amplitude, i.e., the solution of the Schr?dinger equation.
Received: 21 August 1996 / Accepted: 13 February 1997 相似文献
107.
Mizue Fujio Toshikazu Adachi Yoshifumi Shibuya Akihisa Murata Yuho Tsuno 《Tetrahedron letters》1984,25(40):4557-4560
Substituent effects of p-MeO and p-MeS groups deactivated by additional m-substituents in cumyl and α-phenylethyl solvolyses were studied to provide evidence for the higher resonance demand in the α-phenylethyl system. 相似文献
108.
Yutaka Nagai Nakahara Kouji Yoneyama Yoshifumi Kawano Katsuyasu Tanaka Katsumi Nakata Ryouhei 《Journal of Physics and Chemistry of Solids》2004,65(11):1861-1870
The characteristics of high-temperature ionic thermocurrent (HT ITC) in CaF2 doped with different sodium concentrations were studied by the Teflon-insulated electrode ITC method. It was shown that, with increasing sodium concentration, the HT ITC band moved toward a Na+-FV dipole band with a peak at 162 K. The results of analyses of the HT ITC spectra using an equivalent electric circuit proved that the activation energy of space charge migration related to HT ITC was also strongly dependent on the doped sodium concentrations if varied from 0.94 to 0.46 eV with increasing sodium concentration in our ITC study. In addition, the broadening of the Na+-FV dipole band was observed in 3 nominal mole% NaF-doped CaF2, which was accompanied by a considerable decrease of the activation energy from 0.46 to 0.29 eV without showing marked temperature shifts of the peak ITC bands. 相似文献
109.
110.
The atomic and electronic structure of the {211} =3 boundary in diamond has been calculated by using the transferable tight-binding method. Several atomic models with symmetry consistent with the electron microscopy observation have been dealt with. The four-fold coordinated model is the most stable, although its interfacial energy is fairly high as compared with four-fold coordinated configurations in Si and other boundaries in diamond. Thus the models with three-fold coordinated sites may exist partially as defects. The electron energy-loss spectra of this boundary have been calculated by the tight-binding method for the first time. The K-edge spectra of the models with three-fold coordinated sites have small peaks below the bulk conduction-band peak caused by unoccupied gap states. These can explain the increases at the position of the * peak below the * peak in the observed spectra of this boundary. 相似文献