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81.
82.
Polanski J Gieleciak R Magdziarz T Bak A 《Journal of chemical information and computer sciences》2004,44(4):1423-1435
Shape analysis is a powerful tool in chemistry and drug design, and molecular surface defines shape in the molecular scale. In the current publication we presented a novel formalism for the comparative molecular surface analysis (s-CoMSA). The method enables both quantitative modeling of 3D-QSAR and finding possible pharmacophoric sites. The method provides very predictive models for the CBG activity of the benchmark steroid series, tinctorial properties of the heterocyclic azo dyes and anti-HIV activity of the HEPT series. 相似文献
83.
A number of new 15- and 1 8-membered ring aza-crown (4, 5, 8–13, 17, 18) and lariat ethers (6, 7) incorporating glucose or galactose units have been synthesized in good yields by a simple route. Their extracting abilities were measured with Li+, Na+, K+ and NH
4
+
cations. The substituents at the nitrogen atom and the type of monosaccharide affected this property significantly. 相似文献
84.
Summary The ground state (X
1+) and several excited state (A
3,c
3+,C
1,D
1+, andE
3+) potential energy surfaces for the diatomic molecules MgAr, CdAr, and BeAr have been computed using complete active space self-consistent field (CASSCF) wavefunctions and valence double- and triplezeta quality basis sets augmented with polarization and diffuse functions. Pump-and-probe laser experiments have examined the quenching, of excited singlet states of metal-rare gas complexes such as CdXe to produce triplets that dissociate to3
P
Jmetal atoms. This quenching, which is detected for CdXe but not for CdAr or MgAr, is thought to occur via a crossing or strong coupling of a repulsive triplet curve correlating to the underlying3
P state of the metal, with an attractive singlet curve that correlates to the higher1
P state of the metal. The present work indicates that the attractiveC
1 and repulsivec
3+ curves of MgAr and CdArdo not intersect in the energetically accessible region of theC
1 surface, unlike the corresponding curves for the CdXe diatom. These data are consistent with the absence of3
P
J Cd atoms in the MgAr and CdAr experiments, respectively. However, an alternative quenching mechanism involving vibronic coupling between theC
1 vibrational eigenstates and the continuum eigenstates of the underlying repulsive3+ surface may be operative; this possibility is examined qualitatively and predicted to be unlikely for MgAr (due to small spin-orbit coupling) and CdAr (due to unfavorable vibronic factors). BeAr, which has yet to be probed experimentally, is predicted to be bound by 770 and 900 cm–1 in theD
1+ state (which has metal 2s2p character) and theE
3+ state (which has Rydberg metal 2s3s character), respectively, and to display interesting potential curve intersections.Dedicated to Prof. Klaus Ruedenberg 相似文献
85.
In continuation of our studies of the pyrolysis (1000°C) of (CH3)2NCN to alleged CH2=NCN (I), N-cyanoformimine, (CD3)2NCN has been prepared and pyrolyzed (1000°C) to CD2=NCN (II) as seen by its observed rotational transitions (18.6–40.0 GHz). The published rigid structural model of I and a corresponding structure of II are practically identical. 相似文献
86.
87.
Experimental and theoretical studies are made of the consequences of a nonlinear coupling process between pump rf waves and interchange modes in mirror plasmas. It is demonstrated that the interchange-stable operation window exists depending on the applied rf power and gamma=omega(0)/Omega(i), where omega(0) (Omega(i)) is the angular frequency of the applied rf wave (ion cyclotron frequency). Results are shown that the nonlinear wave coupling process gives rise to the operation window near the resonance (gamma approximately equal to 1), which is elucidated by theoretical analyses combined with full rf wave simulations. 相似文献
88.
J. Bak G. Melchart E. Uggerøj J.S. Forster P.R. Jensen H. Madsbøll S.P. Møller H. Nielsen G. Petersen H. Schiøtt J.J. Grob P. Siffert 《Physics letters. [Part B]》1980,93(4):505-508
A very strong and dramatic bending effect has been found for 12 GeV/c positive particles channeled along crystal axes and planes. For a combination of axial and planar channeling the bending efficiency is 5–10%. The maximum bending angle was 52 mrad obtained over a 20 mm long 〈111〉 Si-crystal. The axial channeling is also able to bend negative particles. 相似文献
89.
Chemical kinetics of a system of reacting polymers is modelled by an equation which shares certain properties with Boltzmann's equation. Being more tractable, however, this evolution may be of an illustrative value for the latter. The existence and uniqueness of solutions are analysed. We derive an entropy production inequality which is used to prove global exponential decay of the free energy. With its aid a uniform rate for strong convergence to equilibrium is proven. The generators of the linearlized flow at the vicinity of the equilibria are diagonalized.Work partly supported by U.S. National Science Foundation grant MCS 75-21684 A02 相似文献
90.