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101.
An efficient solvent-free synthesis of various 2,4,5-triaryl imidazoles and 1,2,4,5-tetraaryl imidazoles has been developed using silica chloride as a heterogeneous catalyst. The present methodology offers several advantages, such as excellent yields, shorter reaction times, economic availability, and reusability of catalyst. 相似文献
102.
Developing large scale deposition techniques to fabricate thin porous films with suitable opto-electro nic properties for water catalysis is a necessity to mitigate climate change and have a sustainable environment.In this review,flame spray pyrolysis(FSP)technique,a rapid and scalable methodology to synthesize nanostructured transitional metal oxide films with designed functionalities,is firstly introduced.Furthermore,applications in electrochemical(EC)and photoelectrochemical(PEC)water splitting for the production of hydrogen fuel is also presented.The high combustion temperature and the aggregation of flame aerosol ensure that the FSP-made films possess high crystallinity,tunable porosity and high surface areas,making this method suitable either as catalysts for EC water splitting or as efficient semiconductor materials for PEC water splitting.Finally,a perspective on the next generation FSP engineered films with potential applications in energy storage and conversion is described. 相似文献
103.
V. Anand Ganesh Anupama Sargur Ranganath Radhakrishnan Sridhar Hemant Kumar Raut Sundaramurthy Jayaraman Rahul Sahay Seeram Ramakrishna Avinash Baji 《Macromolecular rapid communications》2015,36(14):1368-1373
Temperature‐triggered switchable nanofibrous membranes are successfully fabricated from a mixture of cellulose acetate (CA) and poly(N‐isopropylacrylamide) (PNIPAM) by employing a single‐step direct electrospinning process. These hybrid CA‐PNIPAM membranes demonstrate the ability to switch between two wetting states viz. superhydrophilic to highly hydrophobic states upon increasing the temperature. At room temperature (23 °C) CA‐PNIPAM nanofibrous membranes exhibit superhydrophilicity, while at elevated temperature (40 °C) the membranes demonstrate hydrophobicity with a static water contact angle greater than 130°. Furthermore, the results here demonstrate that the degree of hydrophobicity of the membranes can be controlled by adjusting the ratio of PNIPAM in the CA‐PNIPAM mixture.
104.
Hemant P. Borase Chandrashekhar D. Patil Rahul K. Suryawanshi Satish V. Patil 《Applied biochemistry and biotechnology》2013,171(3):676-688
The present work provides scientific support on the use of latex of Ficus carica to synthesize stable silver nanoparticles (AgNPs). AgNPs synthesized immediately after the addition of latex to silver nitrate solution at room temperature. Synthesized nanoparticles were of spherical shape with average size of 163.7 nm. Fourier transform infrared spectroscopy analysis revealed capping of proteins and phenolic compound on AgNPs, while X-ray diffraction analysis confirmed the fcc nature of AgNPs. Particles formed were stable for a long time (6 months). It was found that incorporation of AgNPs with 2 and 4 % concentration exhibits synergistic increase in sun protection factor of commercial sunscreen and natural extracts ranging from 01 to 12,175 % than control. Further characterization of latex and AgNPs revealed total phenolic content of 98.75 and 94.88 μg/ml. The ferric ion reduction potentials of latex and AgNPs were 79.69 and 18.79 %. Reduction potential of ascorbic acid was synergistically increased after cumulative preparation of ascorbic acid with latex and AgNPs and found to be 106.76 and 101.50 % for ascorbic acid + latex and ascorbic acid + AgNPs, respectively. 相似文献
105.
The first series of hexaalkenyloxytriphenylenes, where the unsaturation resides at the termini of the side chains, has been synthesised and characterised. Most interestingly, the synthesis of these alkenyloxytriphenylenes, by alkylation of hexahydroxytriphenylene, is found to yield additional products resulting from a single C-alkylation alongside exhaustive O-alkylation; surprisingly several homologues of these materials retain columnar mesophase behaviour. 相似文献
106.
Extensive photophysical properties of isomeric tetra-2-pyridylporphyrin (TpyP(2)), tetra-3-pyridylporphyrin (TpyP(3)), and tetra-4-pyridylporphyrin (TpyP(4)) have been studied in the presence of a series of phenols of increasing hydrogen bonding power in dichloromethane solution by employing UV/vis spectroscopy; steady-state, time-resolved fluorescence spectroscopy; and transient absorption spectroscopic techniques. The change of absorption spectra of all three porphyrins as a function of different phenol concentrations established the preference of hydrogen bonded complex formation to the peripheral pyridyl nitrogen rather than the pyrrole nitrogen of the porphyrin macrocycle. The fluorescence behaviors of the porphyrins which were observed upon addition of different phenols point to a marked dependence on the nature of the added phenols. Phenols with an electron withdrawing group do not quench the fluorescence of porphyrins, whereas phenols with an electron donating group quench the singlet porphyrin both in static and dynamic pathways. A remarkable difference in quenching behaviors of singlet excited porphyrin by 4-methylphenol (4-MePhOH) and 4-MeOPhOH/4-EtOPhOH (4-EtOPhOH = 4-ethoxyphenol) are observed. The quenching of singlet excited porphyrins by 4-MePhOH is attributed to be purely static in nature, and the H-bond provides a strong nonradiative channel to singlet excited porphyrins. However, the quenching of singlet excited porphyrins by 4-MeOPhOH/4-EtOPhOH is mostly dynamic, and it is ascribed to be the reductive quenching of single excited porphyrins. Picosecond transient absorption study with TpyP(2) and 4-MeOPhOH provides the evidence of porphyrin radical anion and phenol radical cation of equal lifetime, which indicates the fact that electron transfer occurs from phenol to singlet excited porphyrin. The temperature effect on dynamic quenching by 4-MeOPhOH/4-EtOPhOH and kinetic deuterium isotope effect established the reaction to be a photoinduced concerted proton coupled electron transfer. 相似文献
107.
Capture and sequestration of green house gas CO(2) is a major challenge for scientists and identifying right materials for this purpose is a task of outstanding importance. Through reliable computational studies, we have demonstrated that the clathrate cages (5(12), 4(3)5(6)6(3), 5(12)6(2), 5(12)6(4), and 5(12)6(8)) have a great potential to store CO(2). All the considered clathrates and their CO(2) inclusion complexes are optimized at B3LYP/6-31G(d) level of theory. The impact of DFT-D, M05-2X, and MP2 functionals on interaction energy were tested using various basis sets. Although different functionals and basis sets show variation in absolute IE values, the trend is consistent and does not depend on the level of the calculations. Dispersion was found important for these complexes and DFT-D shows comparable IE values with MP2 functional. The optimum and maximum cage occupancy for all the considered cages were tested on the basis of quantum chemical calculations. The maximum cage occupancy for all five considered cages (5(12), 4(3)5(6)6(3), 5(12)6(2), 5(12)6(4), and 5(12)6(8)) is one, two, two, two, and seven CO(2) molecules, respectively, and the optimum cage occupancy is one, one, one, two, and five CO(2) molecules, respectively. Thus, 5(12)6(8) cages can host up to 7 CO(2) molecules, resulting in about 32 wt %, which makes them highly promising materials. 相似文献
108.
In this paper, we investigate the peristaltic transport of a couple stress fluid in a channel with compliant walls. Perturbation
method has been used to get the solution. The flow is induced by sinusoidal traveling waves along the channel walls. The effects
of wall damping, wall elastance, wall tension and couple stress parameter on the flow are investigated using the equations
of fluid as well as deformable boundaries. It is found that the mean velocity at boundaries decreases with increasing couple-stress
parameter and wall damping and increases with increasing wall tension and wall elastance, while the mean axial velocity increases
with increasing wall tension and wall elastance and decreases with couple-stress parameter and wall damping. 相似文献
109.
A new series of chalcones, pyrimidines, and imidazolinone is described; chalcones ( 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l , 4m , 4n , 4o ) were prepared from the lead 4‐[2‐(5‐ethylpyridin‐2‐yl)ethoxy]benzaldehyde. Pyrimidines ( 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j , 5k , 5l , 5m , 5n , 5o ) were prepared from the reaction of chalcones and guanidine nitrate in alkali media. Imidazolinones ( 6a , 6b , 6c , 6d , 6e , 6f , 6g , 6h , 6i , 6j , 6k , 6l , 6m , 6n , 6o ) were synthesized from the reaction of pyrimidine and oxazolone derivatives (prepared by Erlenmeyer azlactone synthesis). The structures of the synthesized compounds were assigned on the basis of elemental analyses, IR, 1H‐NMR, and 13C‐NMR spectral data. All the products were screened against different strains of bacteria and fungi. Most of these compounds showed better inhibitory activity in comparison with the standard drugs. J. Heterocyclic Chem., (2011). 相似文献
110.
This paper studies the Stokes flow of micro-polar fluids by peristaltic pumping through the cylindrical tube under the effect
of the slip boundary condition. The motion of the wall is governed by the sinusoidal wave equation. The analytical and numerical
solutions for the axial velocity, the micro-polar vector, the stream function, the pressure gradient, the friction force,
and the mechanical efficiency are obtained by using the lubrication theory under the low Reynolds number and long wavelength
approximations. The impacts of the emerging parameters, such as the coupling number, the micro-polar parameter, the slip parameter
on pumping characteristics, the friction force, the velocity profile, the mechanical efficiency, and the trapping phenomenon
are depicted graphically. The numerical results infer that large pressure is required for peristaltic pumping when the coupling
number is large, while opposite behaviors are found for the micro-polar parameter and the slip parameter. The size of the
trapped bolus reduces with the increase in the coupling number and the micro-polar parameter, whereas it blows up with the
increase in the slip parameter. 相似文献