全文获取类型
收费全文 | 77篇 |
免费 | 1篇 |
专业分类
化学 | 61篇 |
数学 | 10篇 |
物理学 | 7篇 |
出版年
2022年 | 3篇 |
2021年 | 1篇 |
2019年 | 4篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 1篇 |
2013年 | 2篇 |
2012年 | 6篇 |
2011年 | 5篇 |
2010年 | 10篇 |
2009年 | 1篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2006年 | 5篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有78条查询结果,搜索用时 15 毫秒
71.
Central European Journal of Operations Research - Airline alliances provide more flights, include different destinations, and maximize revenues. In an alliance, collaborating airlines can offer... 相似文献
72.
Ayşe Aytaç Veli Deniz Murat Şen El-Sayed Hegazy Olgun Güven 《Radiation Physics and Chemistry》2010,79(3):297-300
The effects of gamma and e-beam irradiation on mechanical and structural properties of nylon 66 (Ny 66), nylon 6 (Ny 6) and poly(ethylene terephthalate) (PET) fabrics used in tyres were investigated. The untreated (greige), treated cords and calendered fabrics were irradiated at different doses. It is found that the effects of high energy irradiation on greige, treated cords and calendered fabrics are similar. No protective effect of compounds used in calendering was observed against radiation-induced oxidative degradation. The deterioration effect of gamma irradiation on mechanical properties is much higher than that of e-beam irradiation for all types of samples. Limiting viscosity numbers of both gamma and e-beam irradiated nylon 6 and nylon 66 cords were found to decrease with increasing dose. It is concluded that PET calendered fabric has higher resistance to ionizing radiation. Ny 6 and Ny 66 calendered fabrics are more sensitive even at low doses. Therefore, the effects of high energy irradiation on tyre cords have to be taken into consideration during tyre design reinforced with particularly Ny fabrics if pre-vulcanization with high energy radiation is to be applied. 相似文献
73.
A proper understanding of the conformational energetics of 1,2-ethanediol (ethylene glycol) is important to the construction of molecular mechanics force fields for the treatment of carbohydrates since these biologically important molecules have a prevalence of vicinal hydroxyl groups. In the present study, quantum mechanical analysis of the 10 unique minimum-energy conformations of ethylene glycol is performed by using 10 model chemistries ranging from HF/6-311++G(d,p) up to a hybrid method that approximates CCSD(T)/cc-pVQZ. In addition, natural bond orbital (NBO) analysis of these conformations with deletion of pairings of CO bond/antibonding and lone pair/antibonding orbitals is used to investigate contributions from the "gauche" effect to ethylene glycol conformational energetics. MP2 with the "correlation consistent" basis sets and DFT/6-311++G(d,p) do the best job of matching the approximate CCSD(T)/cc-pVQZ energies while MP2/6-31G(d) and Hartree-Fock both fare poorly. NBO analysis shows the conformational energies to be independent of the deletion of matrix elements associated with (i) CO bonding and antibonding orbital interactions and (ii) lone pair and antibonding orbital interactions, whereas the energetic ordering correlates with geometric parameters consistent with internal hydrogen bonds. Thus, the present results suggest that standard molecular mechanics potential energy functional forms, which lack explicit terms to account for stereoelectronic effects, are appropriate for carbohydrates. 相似文献
74.
The solubility parameters of pure Poly(n-vinyl 2-pyrrolidone) (PVP) and Poly(n-vinyl 2-pyrrolidone/ethylene glycol dimethacrylate)P(VP/EGDMA) hydrogels have been evaluated via swelling experiments. Twenty solvents with various solubility parameters have been used in the swelling experiments. Considering the limitations of using the approach as developed by Gee, we have applied an asymmetric double sigmodial equation for locating the peak maxima in swelling curves. The solubility parameters are evaluated via this new approach. The solubility parameter of pure PVP is determined to be 11.38 ± 0.11 Hb. The incorporation of EGDMA into the gel system slightly reduced the solubility parameter. The influence of relative amount of EGDMA on the solubility parameter was investigated, and evaluated values compared with literature and theoretically determined solubility values by group contribution values of van Krevelen, Small, and Hoy. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36 : 213–219, 1998 相似文献
75.
76.
K. Vanommeslaeghe E. Hatcher C. Acharya S. Kundu S. Zhong J. Shim E. Darian O. Guvench P. Lopes I. Vorobyov A. D. Mackerell Jr. 《Journal of computational chemistry》2010,31(4):671-690
The widely used CHARMM additive all‐atom force field includes parameters for proteins, nucleic acids, lipids, and carbohydrates. In the present article, an extension of the CHARMM force field to drug‐like molecules is presented. The resulting CHARMM General Force Field (CGenFF) covers a wide range of chemical groups present in biomolecules and drug‐like molecules, including a large number of heterocyclic scaffolds. The parametrization philosophy behind the force field focuses on quality at the expense of transferability, with the implementation concentrating on an extensible force field. Statistics related to the quality of the parametrization with a focus on experimental validation are presented. Additionally, the parametrization procedure, described fully in the present article in the context of the model systems, pyrrolidine, and 3‐phenoxymethylpyrrolidine will allow users to readily extend the force field to chemical groups that are not explicitly covered in the force field as well as add functional groups to and link together molecules already available in the force field. CGenFF thus makes it possible to perform “all‐CHARMM” simulations on drug‐target interactions thereby extending the utility of CHARMM force fields to medicinally relevant systems. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010 相似文献
77.
Radiation induced acid doping of PANI to generate electrical conductivity was achieved by radiation induced HCl release from chlorinated-polyisoprene (ClPIP). Blends of PANI with ClPIP were prepared by mechanical mixing/grinding in the composition range of 9–43% ClPIP by weight and pelletized under 10 t press. The pellets were irradiated in 60Co Gammacell in air at room temperature to doses up to 300 kGy. The maximum electrical conductivity increase was observed for the blend PANI43 which changed from 10?10 to 10?4 S cm?1 when it was irradiated to 300 kGy dose. Radiation induced changes on the blends were also studied by UV–vis spectroscopy using reflection technique and FTIR spectroscopy. The broad absorption band in the visible range (630 nm) increased by increasing irradiation dose. The band (1110 cm?1) in the IR spectra which is indicative of conductivity showed linear correlation with irradiation dose. 相似文献
78.
Mert Olgun Karata Gamze algn Bülent Alc Baak Gke Nahit Gener Tuba Takn Tok Oktay Arslan In Kl‐Ckla Namk
zdemir 《应用有机金属化学》2019,33(10)
We synthesized three coumarin‐substituted benzimidazolium chlorides and their silver(I), ruthenium(II) and palladium(II) N‐heterocyclic carbene (NHC) complexes. All compounds were characterized using appropriate spectroscopic techniques and elemental analyses. Single‐crystal X‐ray structure of a Pd(II)–NHC complex ( 6b ) was also determined. The inhibitory properties of all compounds were tested on the activity of human paraoxonase 1 (PON1). All complexes exhibited weaker inhibitory properties than their corresponding benzimidazolium salts except for complex 6b which is the most active inhibitor with an IC50 value of 3.01 μM among the compounds reported in this study. A kinetic evaluation showed that this complex inhibits PON1 activity in a non‐competitive manner. Molecular docking studies were also performed for 6b in order to obtain more insight into the binding mode. 相似文献