全文获取类型
收费全文 | 68篇 |
免费 | 1篇 |
专业分类
化学 | 55篇 |
晶体学 | 1篇 |
数学 | 1篇 |
物理学 | 12篇 |
出版年
2015年 | 3篇 |
2013年 | 4篇 |
2005年 | 1篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 5篇 |
1971年 | 1篇 |
1968年 | 2篇 |
1967年 | 12篇 |
1965年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有69条查询结果,搜索用时 296 毫秒
1.
KL Britton HF Rogers Y Asano T Dairi Y Kato TJ Stillman DW Rice 《Acta crystallographica. Section D, Biological crystallography》1998,53(4):124-126
The novel NAD+-linked opine dehydrogenase from a soil isolate Arthrobacter sp. strain 1C belongs to an enzyme superfamily whose members exhibit quite diverse substrate specificites. Crystals of this opine dehydrogenase, obtained in the presence or absence of co-factor and substrates, have been shown to diffract to beyond 1.8 ? resolution. X-ray precession photographs have established that the crystals belong to space group P21212, with cell parameters a = 104.9, b = 80.0, c = 45.5 ? and a single subunit in the asymmetric unit. The elucidation of the three-dimensional structure of this enzyme will provide a structural framework for this novel class of dehydrogenases to enable a comparison to be made with other enzyme families and also as the basis for mutagenesis experiments directed towards the production of natural and synthetic opine-type compounds containing two chiral centres. 相似文献
2.
The C2H4 was investigated ab initio for the equilibrium distance of the centers, taking all 16 electrons into account, using the Allgemeines Programmsystem/SCF ? MO ? LC (LCGO ) Methode. A total energy of ?76.77 a.u. and an ionization energy of 10.55 eV were found. 相似文献
3.
Many-body perturbation theory is used for the calculation of the quadrupole polarizability of the Be atom within the finite-field perturbation scheme. The correlation corrections exhibit a considerable dependence on the f-type orbital exponents and the final results are in the range 287–294 au. The convergence of the correlation perturbation series is discussed. 相似文献
4.
The (Li2H)+ has been investigated ab initio in the linear configuration, with the H atom in the middle of the system, for five different distances RLiH, taking all six electrons into account, using the Allgemeines Programmsystem/SCF? MO? LC(LCGO) Verfahren. A bond distance RLiH of 3.14 a.u., a total energy of ?15.289 a.u., and an ionization energy of 15.1 eV were found. Comparing the results of SCF investigations, the formation energy of (Li2H)+ from LiH and Li+ was computed to be 59.7 kcal/mole (2.58 eV). Using the energy curve near the minimum, a force constant for the symmetric vibration of k = 0.13777 × 106 dyn/cm and a frequency ω = 577.9 cm?1 were found. 相似文献
5.
The expressions for Rosen–Morse Franck–Condon factors derived previously yield a double sum with alternating terms. For higher
values of the quantum number the numerical calculation of the Franck–Condon factors by electronic computers using these expressions
leads to numerical overflow inspite of the use of double-precision (32 digits) arithmetic. High values for the quantum number
in the final ground state of the Rosen–Morse potential occur in molecular nonradiative rate calculations. Furthermore, the
expressions show a lack of clearness with respect to the parameters of the potential. For out-of-plane modes exact closed
form expressions and exact recurrence relations are derived. Asymptotic expressions for the matrix elements are calculated.
Exact closed form expressions for matrix elements with quantum numbers which correspond to regions close to the dissociation
barrier are given.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
7.
The energy surfaces of the systems LiOH
2
+
and NaOH
2
+
are studied for a number of different geometries within the SCF MO LCAO framework, using a gaussian basis set to approximate the wavefunction. In the minimum energy geometry of both systems the positive ion is bound to the oxygen atom of the water molecule. The computed binding energies and bond distances are: B
SCF(LiOH
2
+
) = 36.0 kcal/mole, d(LiO) = 3.57 a.u., and B
SCF(NaOH
2
+
) = 25.2 kcal/mole, d(NaO) = 4.23 a.u., resp. The results are compared with those of H3O+ and discussed in view of ion-solvent interaction in aquous solutions.It is a pleasure to thank our technical staff for the careful preparation of the input for the programs and for its enthusiastic and skilful assistance in running the computer. 相似文献
8.
Ohne Zusammenfassung
Wir danken Herrn Prof. Dr. H. Hartmann für das Interesse an dieser Arbeit und die Förderung der Untersuchungen. Einer von uns (G. D.) dankt ferner der Deutschen Forschungsgemeinschaft für ein Stipendium. 相似文献
A punch card index for documentation of quantum chemistry
Une documentation de la chimie quantique à l'aide des cartes perforées
Wir danken Herrn Prof. Dr. H. Hartmann für das Interesse an dieser Arbeit und die Förderung der Untersuchungen. Einer von uns (G. D.) dankt ferner der Deutschen Forschungsgemeinschaft für ein Stipendium. 相似文献
9.
The many-body perturbation theory is employed for the calculation of the interaction potential for the F- … He system in the framework of the supermolecule method. A particular attention is paid to the choice of the basis set functions for the two subsystems and the related basis set superposition effects. It has been found that the main features of the interaction potential are recovered in the SCF approximation. The SCF potential has its minimum at the distance R = 6·4 a 0 with the interaction energy of 53 cm-1. The complete fourth-order MBPT method gives the potential minimum position and depth equal to 6·5 a 0 and 64 cm-1, respectively. The basis set superposition effects estimated by using the counterpoise technique are negligibly small for the SCF interaction potential, while at the correlated level their magnitude is comparable to the value of the total correlation contribution to the interaction energy. The basis set superposition effect in calculations of the electron correlation contribution to weak intermolecular interactions is found to be the major factor limiting the reliability of the corresponding theoretical data. 相似文献
10.
Tatiana Korona Bogumil Jeziorski Robert Moszynski Geerd H. F. Diercksen 《Theoretical chemistry accounts》1999,101(4):282-291
Symmetry-adapted perturbation theory is extended to the (quasi) degenerate, open-shell case. The new formalism is tested
in calculations of the interaction energies for a helium atom in the ground state interacting with an excited hydrogen atom.
It is shown that the method gives satisfactory results if the coupling with higher Rydberg states of the dimer is small, as
is the case for the A2Σ+,B2Π,E2Π,32Π, and 12Δ states of HeH. For the C2Σ+ state convergence of the method is very slow, but it can be improved by including the n=3 states in the model space.
Received: 3 June 1998 / Accepted: 9 September 1998 / Published online: 7 December 1998 相似文献