全文获取类型
收费全文 | 1965篇 |
免费 | 43篇 |
国内免费 | 6篇 |
专业分类
化学 | 1196篇 |
晶体学 | 10篇 |
力学 | 36篇 |
数学 | 195篇 |
物理学 | 577篇 |
出版年
2022年 | 13篇 |
2021年 | 21篇 |
2020年 | 24篇 |
2019年 | 12篇 |
2018年 | 19篇 |
2016年 | 28篇 |
2015年 | 27篇 |
2014年 | 36篇 |
2013年 | 73篇 |
2012年 | 91篇 |
2011年 | 132篇 |
2010年 | 49篇 |
2009年 | 46篇 |
2008年 | 97篇 |
2007年 | 95篇 |
2006年 | 105篇 |
2005年 | 104篇 |
2004年 | 99篇 |
2003年 | 90篇 |
2002年 | 86篇 |
2001年 | 55篇 |
2000年 | 51篇 |
1999年 | 15篇 |
1998年 | 19篇 |
1997年 | 20篇 |
1996年 | 32篇 |
1995年 | 17篇 |
1994年 | 35篇 |
1993年 | 38篇 |
1992年 | 40篇 |
1991年 | 37篇 |
1990年 | 25篇 |
1989年 | 23篇 |
1988年 | 14篇 |
1987年 | 11篇 |
1986年 | 19篇 |
1985年 | 23篇 |
1984年 | 18篇 |
1983年 | 20篇 |
1982年 | 10篇 |
1981年 | 11篇 |
1980年 | 14篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 9篇 |
1976年 | 10篇 |
1975年 | 14篇 |
1974年 | 11篇 |
1973年 | 23篇 |
1967年 | 10篇 |
排序方式: 共有2014条查询结果,搜索用时 15 毫秒
61.
The vibrational frequencies and corresponding normal mode assignments of urazole are examined theoretically using the Gaussian98 set of quantum chemistry codes. All normal modes were successfully assigned to one of eight types of motion (N--H stretch, C=O stretch, C--N stretch, N--N stretch, N--H bend, C=O bend, N--C--N bend, ring torsion) utilizing the C2 symmetry of the molecule. The molecular orbitals of urazole are examined. The simultaneous double inversion of the amine groups in urazole is also examined. 相似文献
62.
Jensen JO 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2004,60(11):2561-2566
The normal mode frequencies and corresponding vibrational assignments of Triethynylmethylstannane (SnCH(3)(CCH)(3)) are examined theoretically using the Gaussian 98 set of quantum chemistry codes. Each of the vibrational modes was assigned to one of nine types of motion predicted by a group theoretical analysis (Sn-C stretch, C[triple bond]C stretch, C-H stretch, C[triple bond]C-H bend, Sn-C[triple bond]C bend, C-Sn-C bend, H-C-H bend, CH(3) wag, and CH(3) twist) utilizing the C(3v) symmetry of the molecule. A set of uniform scaling factors was derived for each type of motion. Predicted infrared and Raman intensities are reported. 相似文献
63.
64.
65.
66.
67.
Fulton R Jensen T Johnson DR Kagan H Kass R Morrow F Whitmore J Wilson P Bortoletto D Chen W Dominick J McIlwain RL Miller DH Ng CR Schaffner SF Shibata EI Shipsey IP Yao W Battle M Sparks K Thorndike EH Wang C Alam MS Kim IJ Li WC Romero V Sun CR Wang P Zoeller MM Goldberg M Haupt T Horwitz N Jain V Mestayer MD Moneti GC Rozen Y Rubin P Sharma V Skwarnicki T Thulasidas M Zhu G Csorna SE Letson T Alexander J Artuso M Bebek C Berkelman K Browder T Cassel DG Cheu E Coffman DM Crawford G DeWire JW 《Physical review D: Particles and fields》1991,43(3):651-663
68.
Kubota Y Nelson JK Perticone D Poling R Schrenk S Crawford G Fulton R Jensen T Johnson DR Kagan H Kass R Malchow R Morrow F Whitmore J Wilson P Bortoletto D Brown D Dominick J McIlwain RL Miller DH Modesitt M Ng CR Schaffner SF Shibata EI Shipsey IP Battle M Kroha H Sparks K Thorndike EH Wang C Alam MS Kim IJ Li WC Nemati B Romero V Sun CR Wang P Zoeller MM Goldberg M Haupt T Horwitz N Jain V Mestayer MD Moneti GC Rozen Y Rubin P Skwarnicki T Stone S Thusalidas M Yao W Zhu G Barnes AV Bartelt J 《Physical review D: Particles and fields》1991,44(3):593-600
69.
J. P. Tovborg Jensen J. Kops 《Journal of polymer science. Part A, Polymer chemistry》1980,18(8):2737-2746
Blends of polystyrene and poly(2,6-dimethyl-1,4-phenylene oxide) that cover the entire compositional range have been subjected to the action of singlet oxygen from microwave discharge, dye-sensitized reaction, and photochemical oxidation. With the applied analytical technique, which consisted of infrared (IR) analysis, including ATR technique and a spectroscopic method combined with chemical analysis for hydroperoxide groups, it was not possible to detect any effect of the singlet oxygen treatment. For that reason singlet oxygen does not appear to be important to the initiation of the photooxidation of these blends. In connection with photochemical oxidation the interaction observed between the two components probably involves energy transfer from PS to PPO. This interaction results in the enhancement of reactions in PPO that lead to greater carbonyl group formation and crosslinking. Simultaneously, the probability of chain scission in the PS is lowered with increased PPO content, found by determining the changes in the molecular weights. 相似文献
70.
The normal mode frequencies and corresponding vibrational assignments of tert-butylacetylene (TBA) are examined theoretically using the Gaussian 98 set of quantum chemistry codes. All normal modes were successfully assigned to one of the nine types of motion (C---C stretch, CC stretch, C---H stretch, C---C---C bend, CC---C bend, CC---H bend, H---C---H bend, CH3 rock, and CH3 twist) utilizing the C3v symmetry of the molecule. Calculations were performed at the Hartree–Fock, B3LYP, and MP2 levels of theory using the standard 6-311G** basis. Theoretical results were successfully compared against available experimental data. 相似文献