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111.
This study presents a set of the generalized parameters from a unique resource for the elements which are from the first-period to the fourth-period (H to Xe). In addition, these series of parameters are used to examine forty-five compounds consisting of the fourth-period elements and the second-period transition metal elements. Herein, the major calculation theory applied is the s-p-d INDO MO method. To verify the reliability of the molecular calculations, similar calculations of the STO-3G and STO-3G* ab inito methods, along with the semiempirical PM3 and AM1 methods are also compared. Results in this study demonstrate that the s-p-d INDO MO computed with the generalized parameter is the best available method. 相似文献
112.
Alexander Shluger 《Theoretical chemistry accounts》1985,66(6):355-363
A modified calculation scheme of the INDO method is applied for calculating the electronic structure of perfect and imperfect oxide crystals. In order to obtain a flexible scheme permitting reliable calculation of both the electronic structure and the defect conformations, the INDO parameters for H, Li, Mg, Si, O are fitted directly to reproduce one-electron energies as well as the vicinity of the potential energy curve minima for a series of diatomic molecules and the electronic structure of MgO and -crystoballite form of SiO2. The method is tested on the Li2SiO3 crystal calculated within the framework of the large unit cell model. 相似文献
113.
Diane C. Rawlings Ernest R. Davidson Martin Gouterman 《Theoretical chemistry accounts》1982,61(3):227-241
Symmetry instabilities were encountered during MINDO/3 geometry optimizations of the sirohydrochlorin and porphine isomers leading to bond alternating optimal structures. Transition energies and oscillator strengths were calculated with INDO/S/CI. Our calculations predict the ground state cis and trans isomers of sirohydrochlorin to be close in energy and confirm the experimental assignment of the absorptions bands, with the cis tautomer having a red shifted spectrum.Part 41. Gouterman, M., Sayer, P., Shankland, E., Smith, J. P.: Inorg. Chem. 20, 87 (1981) 相似文献
114.
Intermediate neglect of differential overlap (INDO) calculations were used to study the structure of C75B?—the isoelectronic molecule of C76. It was found that the boron atom mainly substitutes the second carbon atom (there are 19 types of carbon atoms in C76). The electronic spectra of all the possible isomers of C75B? were calculated based on the optimized geometries. It was shown that the UV‐Vis spectra of C75B? and C76 resemble each other in many ways with the exception of the absorptions beyond 700 nm. The red shift of the absorptions was rationalized and nature of transition of the peaks discussed. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003 相似文献
115.
INDO SCF MO calculations are reported for the complexes (C5H5)M(C7H7) (M = Ti, V and Cr), and for the corresponding V and Cr cations. The results correctly predict1
A
1 ground states for the V+ and the neutral Ti and Cr species, and for the neutral V and Cr+ complexes confirm the2
A
1 ground levels. The formally metald-levels followed theH
core sequencee
2<a
1<e
1, and the most important interactions were those between the metale
2 level and the ligand C7H7 -orbitals, and between the metale
1 level and the ligand C5H5 -orbitals. Calculations also satisfactorily reproduced other experimental quantities, and the results indicate that thee
2 ligand interaction becomes more important, and thee
1 ligand interaction less important, with increasing size of the ligand ring. 相似文献
116.
用INDO(Intermediate neglect differential overlap)系列方法对Cn78进行系统研究.结果表明,Cn78(G2v)比Cn78(C2v')稳定;Cn78(C2v)和Cn78(C2v')未发生Jahn-Teller畸变;Cn78随n绝对值增大,体系能量升高.以优化构型为基础,首次计算Cn78电子光谱,对电子跃迁进行理论指认,讨论Cn78光谱特征吸收与C78相比发生红移的原因. 相似文献
117.
Intermediate neglect of differential overlap (INDO) is the most commonly utilized semiempirical technique for performing excited state calculations on large organic systems such as organic semiconductors and fluorescent dyes. The calculations are typically done at the singles-configuration interaction (SCI) level. Direct methods provide a more efficient means of performing configuration interaction (CI) calculations, and the computational trade offs associated with various approaches to direct-CI theory have been well characterized for ab initio Hamiltonians and high-order CI. However, the INDO and SCI approximations lead to a new set of trade offs. In particular, application of the electron-electron interactions in the atomic basis leads to savings in computational time that scale as the number of atomic orbitals, which for a large organic system can be two to three orders of magnitude. These savings are largest when only a few low-lying excited states are generated and when a full SCI basis, which includes excitations between all filled and empty molecular orbitals, is used. In addition, substantial memory savings are achieved in the direct method by avoiding the evaluation of the two electron integrals in the molecular orbital basis. The method is demonstrated by calculating the absorption spectrum of a poly(paraphenylenevinylene) oligomer containing 16 phenyl rings. 相似文献
118.
119.
C60亮氨酸衍生物的合成及其理论研究 总被引:1,自引:1,他引:0
用1,3-偶极环加成方法合成了含吡咯环C60衍生物C66NH13,并以FTIR、UV-Vis、1HNMR和LD-TOFMS进行表征.用AM1方法对两种可能的加成产物-[6,6]和[6,5]异构体进行几何构型优化.结果表明,[6,6]异构体更稳定.以优化构型为基础,用INDO/CI方法计算两种加成产物的UV谱,结果表明,[6,6]异构体的特征吸收与实验值一致.本文对这两种异构体的电子跃迁进行理论指认,并分析了光谱红移的原因. 相似文献
120.