全文获取类型
收费全文 | 170篇 |
免费 | 10篇 |
专业分类
化学 | 131篇 |
晶体学 | 2篇 |
数学 | 11篇 |
物理学 | 36篇 |
出版年
2024年 | 2篇 |
2023年 | 1篇 |
2022年 | 7篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2016年 | 10篇 |
2015年 | 8篇 |
2014年 | 11篇 |
2013年 | 14篇 |
2012年 | 15篇 |
2011年 | 14篇 |
2010年 | 6篇 |
2009年 | 5篇 |
2008年 | 12篇 |
2007年 | 8篇 |
2006年 | 2篇 |
2005年 | 3篇 |
2004年 | 6篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 6篇 |
1998年 | 3篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
排序方式: 共有180条查询结果,搜索用时 15 毫秒
171.
We synthesized a benzthiazole-based chemosensor with mixed S,N donor sites. The binding units are incorporated in a highly flexible tripodal framework which facilitates the complexation of the binding of larger-sized metals. The chemosensor resulted in the sensitive and selective recognition of Ba2+ through the enhancement of the fluorescence intensity when studied in a THF/H2O (8:2, v/v) solvent mixture. The sensor offers an interesting opportunity to monitor Ba2+ in biological samples including the cytoplasm of microbes such as Saccharomyces cerevisiae. 相似文献
172.
Azidation of 1,2-anhydro sugars with NaN(3) in CH(3)CN by using a catalytic amount of ceric ammonium nitrate has been accomplished in a regio- and stereoselective manner. Various 1,2-anhydro sugars produced 2-hydroxy-1-azido sugars in good yields which, in turn, were converted to structurally diverse sugar-derived morpholine triazoles and sugar oxazin-2-ones. These sugar derivatives were tested against various commercially available glycosidases, and two of them were found to be active in the micromolar range. 相似文献
173.
Preeti Gupta Tanvi Agrawal S. S. Das N. B. Singh 《Journal of Thermal Analysis and Calorimetry》2011,104(3):1167-1176
Reactions of nitrophenols have been studied in the eutectic melt of 8-hydroxyquinoline–benzoic acid, where it reacted with
8-hydroxyquinoline. The reactions were also carried out in solution. The reaction products obtained from both the methods
were characterized by FT-IR, differential scanning calorimetry, X-ray diffraction technique and microstructural investigations.
The reaction products obtained from eutectic melt were analyzed for C, H, N. The results showed that reaction products obtained
from both the methods are same. An attempt has been made to propose the overall mechanism of the reaction in the eutectic
melt. 相似文献
174.
The free vibration analysis of simply supported box-girder bridges is carried out using the finite element method. The fundamental frequency is determined in straight, skew, curved and skew-curved box-girder bridges. It is important to analyse the combined effect of skewness and curvature because skew-curved box-girder bridge behaviour cannot be predicted by simply adding the individual effects of skewness and curvature. At first, an existing model is considered to validate the present approach. A convergence study is carried out to decide the mesh size in the finite element method. An exhaustive parametric study is conducted to determine the fundamental frequency of box-girder bridges with varying skew angle, curve angle, span, span-depth ratio and cell number. The skew angle is varied from 0° to 60°, curve angle is varied from 0° to 60°, span is changed from 25 to 50 m, span-depth ratio is varied from 10 to 16, and single cell & double cell are used in the present study. A total of 420 bridge models are used for parametric study in the investigation. Mode shapes of the skew-curved bridge are also presented. The fundamental frequency of the skew-curved box-girder bridge is found to be more than the straight bridge, so, the skew-curved box-girder bridge is preferable. The present study may be useful in the design of box-girder bridges. 相似文献
175.
Phase diagram studies of succinonitrile-vanillin system show the formation of 2:1 congruent melting type compound. Crystallization velocities of pure components, succinonitrile-vanillin complex, and two eutectics have been determined at different undercoolings. On the basis of heat of fusion measurements, excess thermodynamic functions have been calculated. Microstructural studies revealed that impurities modify the morphology. FTIR spectral studies and computer simulation have shown the existence of hydrogen bonding in the eutectics and the congruent melting compound. On the basis of experimental results, the mechanism of formation of eutectics and its solidification behavior are discussed. 相似文献
176.
Synthesis of high aspect ratio quantum-size CdS nanorods and their surface-dependent photoluminescence 总被引:1,自引:0,他引:1
Saunders AE Ghezelbash A Sood P Korgel BA 《Langmuir : the ACS journal of surfaces and colloids》2008,24(16):9043-9049
Colloidal CdS nanorods with diameters near 4 nm and narrow size distributions ( approximately +/-10%) were synthesized up to 300 nm long by a sequential reactant injection technique that utilizes phosophonic acids as capping ligands. The phosphonic acid strongly passivates the nonpolar CdS surfaces and sequential reactant injection provides controlled CdS formation kinetics to enable heterogeneous and facet-selective CdS deposition on the more reactive {002} surfaces. With this process, the nanorod length can be systematically increased by increasing reactant addition to extend nanorod growth. The phosphonic acid concentration, however, is quite important, as "low" concentrations allow radial deposition and branching to occur. These high aspect ratio (>100) CdS nanorods luminesce with relatively high efficiencies of 10.8% quantum yield at room temperature. The luminescence, however, mostly arises from trap-related recombination, and the emission is significantly red-shifted from the absorption edge. Various surface passivation treatments were explored to eliminate trap emission and increase the luminescence quantum yield. Thiol and amine passivation both significantly reduced trap emission and enhanced band-edge emission, but the total luminescence quantum yields dropped significantly, with a maximum measured value of 1.5% for the amine-passivated CdS nanorods. 相似文献
177.
We prove the existence of a global attractor for the Newton–Boussinesq equation defined in a two-dimensional channel. The asymptotic compactness of the equation is derived by the uniform estimates on the tails of solutions. We also establish the regularity of the global attractor. 相似文献
178.
A self-consistent Landau phenomenological approach has been used to study the ferroelectric transition in films in the presence of various surface effects such as depolarization and strain. The polarization distribution of the film is computed and its variation with respect to temperature, thickness and strain is determined. The gradual decrease in polarization across the transition shows the diffusive behavior which is confirmed from the soft mode and the dielectric susceptibility analysis. The critical thickness below which ferroelectricity disappears is also computed. The degree of diffuseness in the transition is obtained from the susceptibility exponent which shows more and more diffusive behavior for smaller and smaller film thickness. 相似文献
179.
Himanshu Kakkar Nalini Chaudhary Devashish Mehta Varsha Saini Shallu Maheshwari Jitender Singh Preeti Walia Avinash Bajaj 《Molecules (Basel, Switzerland)》2022,27(11)
Infections associated with Gram-positive bacteria like S. aureus pose a major threat as these bacteria can develop resistance and thereby limit the applications of antibiotics. Therefore, there is a need for new antibacterials to mitigate these infections. Bacterial membranes present an attractive therapeutic target as these membranes are anionic in nature and have a low chance of developing modifications in their physicochemical features. Antimicrobial peptides (AMPs) can disrupt the microbial membranes via electrostatic interactions, but the poor stability of AMPs halts their clinical translation. Here, we present the synthesis of eight N-methyl benzimidazole substituted cholic acid amphiphiles as antibacterial agents. We screened these novel heterocyclic cholic acid amphiphiles against different pathogens. Among the series, CABI-6 outperformed the other amphiphiles in terms of bactericidal activity against S. aureus. The membrane disruptive property of CABI-6 using a fluorescence-based assay has also been investigated, and it was inferred that CABI-6 can enhance the production of reactive oxygen species. We further demonstrated that CABI-6 can clear the pre-formed biofilms and can mitigate wound infection in murine models. 相似文献
180.
There is much to celebrate in 2023, not least it is EurJIC's 25th Anniversary. Twenty-five years ago, the Dutch and German chemical societies (KNCV and GDCh) took the initiative to create strong European journals with a global reach. Cooperation with more European national chemical societies soon followed, and the amalgamation of their national journals led to the formation of EurJIC under the ownership of Chemistry Europe . With its strong European roots, EurJIC has since developed into a leading inorganic chemistry journal serving an international community. 相似文献