全文获取类型
收费全文 | 118篇 |
免费 | 0篇 |
专业分类
化学 | 87篇 |
晶体学 | 2篇 |
力学 | 1篇 |
数学 | 6篇 |
物理学 | 22篇 |
出版年
2023年 | 1篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2014年 | 3篇 |
2013年 | 14篇 |
2012年 | 2篇 |
2011年 | 2篇 |
2010年 | 5篇 |
2009年 | 5篇 |
2008年 | 5篇 |
2007年 | 7篇 |
2006年 | 2篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1976年 | 4篇 |
1974年 | 4篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1960年 | 1篇 |
1956年 | 1篇 |
1935年 | 2篇 |
排序方式: 共有118条查询结果,搜索用时 0 毫秒
31.
S. Munichandra Reddy D. Subba Rao K. Madhu Ch. Subramanyam P. Gnana Kumari 《Phosphorus, sulfur, and silicon and the related elements》2018,193(3):136-140
A series of new 2-(benzo[d]thiazol-2-yl) phenyl-4-nitrophenyl alkyl/aryl substituted phosphoramidate derivatives (7a-j) of biological interest are synthesized in two steps via an in situ process without the isolation of the intermediate. 2-(Benzo[d]thiazol-2-yl) phenol (3) was treated with 4-nitrophenyl phosphorodichloridate(4) to obtain the monochloro intermediate, 2-(benzo[d]thiazol-2-yl)phenyl (4-nitrophenyl) phosphorochloridate(5). It was subsequently reacted with various amines, 6(a-j) to afford the desired title products. IR, NMR (1H, 13C and 31P), mass spectral and elemental analysis are used to characterize the structures of the newly synthesized compounds. The antibacterial and antifungal activities are determined by the growth of inhibition of bacteria and fungi of the title compounds at two concentrations, 50 and 100 µg/mL, and minimum inhibitory concentrations to the active compounds. The compounds 7e, 7f and 7j exhibited promising inhibition activity against bacterial strains and 7c, 7e and 7i against A. niger and C. albicans and MIC values are in the range of 10.0–15.0 µg/mL. 相似文献
32.
Ch. Subramanyam K. Venkata Ramana S. Rasheed S. Adam C. Naga Raju 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):1228-1235
Abstract An efficient synthesis of a series of novel diphenyl N-substituted carbamimidoyl phosphoramidate derivatives was accomplished in two steps. Diphenyl phosphorochloridate (1) was reacted with cyanamide (2) in the presence of 1,4–dimethylpiperazine as a base in THF at 50–55 °C to form an intermediate, diphenyl cyanophosphoramidate (3). Subsequently 3 was reacted with various aromatic/heterocyclic amines (4) in the presence of 1,4–dimethyl piperazine as a base at 55–60 °C to form the corresponding title compounds 5(a-k). The title compounds were tested for antiviral activity against Tobacco mosaic virus (TMV) in vitro, antibacterial and antifungal activities at two different concentrations of 50 and 100 μg/mL. The title compounds exhibited good antiviral and antimicrobial activities when compared to the standards. 相似文献
33.
Ragha Suma V. Sreenivasulu R. Subramanyam M. Rao K. Ram Mohan 《Russian Journal of General Chemistry》2019,89(3):499-504
A new series of amide derivatives of structurally modified combretastatin-A4 10a–10j are synthesized, and their structures are confirmed by 1H and 13C NMR, and mass spectral data. The products are tested for their anticancer activity towards human cancer cell lines, MCF-7 (breast), A-549 (lung), Colo-205 (colon), and A-2780 (ovarian). The compounds 10b, 10c, and 10d demonstrate the most promising activity.
相似文献34.
The synthesis of orthogonally protected Fmoc‐Dap/Dab (Boc/Z/Alloc)‐OH starting from Fmoc‐Asp/Glu has been described. The salient features of our synthetic strategy involved formation of Fmoc‐Asp/Glu‐5‐oxazolidinone acids, conversion of acid function to acyl azides, Curtius rearrangement, and hydrolysis of the oxazolidinone group. 相似文献
35.
Botulinum neurotoxins are one of the most poisonous biological substances known to humans and present a potential bioterrorism threat. There are no therapeutic interventions developed so far. Here, we report the first small molecule non-peptide inhibitor for botulinum neurotoxin serotype E discovered by structure-based virtual screening and propose a mechanism for its inhibitory activity. 相似文献
36.
Dr. Fadlilatul Taufany Dr. Chun‐Jern Pan Feng‐Ju Lai Dr. Hung‐Lung Chou Loka Subramanyam Sarma Dr. John Rick Jhih‐Min Lin Dr. Jyh‐Fu Lee Dr. Mau‐Tsu Tang Prof. Bing‐Joe Hwang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(3):905-915
A controlled composition‐based method—that is, the microwave‐assisted ethylene glycol (MEG) method—was successfully developed to prepare bimetallic PtxRu100?x/C nanoparticles (NPs) with different alloy compositions. This study highlights the impact of the variation in alloy composition of PtxRu100?x/C NPs on their alloying extent (structure) and subsequently their catalytic activity towards the methanol oxidation reaction (MOR). The alloying extent of these PtxRu100?x/C NPs has a strong influence on their Pt d‐band vacancy and Pt electroactive surface area (Pt ECSA); this relationship was systematically evaluated by using X‐ray absorption (XAS), scanning electron microscopy (SEM) coupled with energy dispersive X‐ray spectroscopy (EDX), transmission electron microscopy (TEM), density functional theory (DFT) calculations, and electrochemical analyses. The MOR activity depends on two effects that act in cooperation, namely, the number of active Pt sites and their activity. Here the number of active Pt sites is associated with the Pt ECSA value, whereas the Pt‐site activity is associated with the alloying extent and Pt d‐band vacancy (electronic) effects. Among the PtxRu100?x/C NPs with various Pt:Ru atomic ratios (x=25, 50, and 75), the Pt75Ru25/C NPs were shown to be superior in MOR activity on account of their favorable alloying extent, Pt d‐band vacancy, and Pt ECSA. This short study brings new insight into probing the synergistic effect on the surface reactivity of the PtxRu100?x/C NPs, and possibly other bimetallic Pt‐based alloy NPs. 相似文献
37.
Viscosities of binary mixtures, benzene + benzonitrile, benzene + methylpropylketone and cyclohexane + methylpropylketone
were determined at 303·15 K. The experimental results were analysed in the light of Bloomfleld and Dewan’s theory. The analysis
showed that the theory correctly predicts the sign of viscosity function in the case of benzene + benzonitrile and cyclohexane
+ methylpropylketone. 相似文献
38.
The anomalies of the second order elastic constants have been derived for barium titanate for the phase transition from cubic
to tetragonal. The equilibrium values of the components of the order parameter and the strain variables have been obtained
from the stability conditions. The fluctuations in the order parameter have been derived from the Landau-Khalatnikov equations.
Expression for the shift in the zero point energy in the tetragonal phase is obtained and is shown to be proportional to (T −T
c)2. The anomalies for all the second order elastic constants have been derived and relations among them reported. It is shown
that the second order elastic anomalies suffer a discontinuity at the transition temperature. 相似文献
39.
The cylindrical approximation originally proposed by Pippard for the λ-transitions in one-component systems is extended to multicomponent systems. The application of the generalised Pippard relations to binary liquid mixtures is considered. The relations for He3 + He4 mixtures are shown to be equivalent to those obtained by earlier workers. The validity of the relation relating specific heat and thermal expansion for binary liquid systems is discussed on the basis of the measurements performed on the system methaonl +n-heptane. Lack of information on the behaviour of a few quantities prevents a quantitative test of the relation. 相似文献
40.
[reaction: see text] Two separate strategies have been developed for the preparation of highly substituted pyridines from 1,2,4-triazines via the inverse-electron-demand Diels-Alder reaction: a microwave-promoted, solvent-free procedure and a tethered imine-enamine (TIE) approach. Both routes avoid the need for a discrete aromatization step and offer significant advantages over the classical methods, giving a wide variety of tri-, tetra-, and penta-substituted pyridines in high, optimized yields. 相似文献