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71.
Abul K. Mallik Wee Keat Cheah Kaori Shingo Aika Ejzaki Makoto Takafuji Hirotaka Ihara 《Analytical and bioanalytical chemistry》2014,406(19):4585-4593
A new hydrophilic and nonionic poly(2-vinyloxazoline)-grafted silica (Sil-VOX n ) phase was synthesized and applied for the separation of nucleosides and nucleobases in hydrophilic interaction chromatography (HILIC). Polymerization and immobilization onto silica were confirmed by using characterization techniques including 1H NMR spectroscopy, elemental analysis, and diffuse reflectance infrared Fourier transform spectroscopy. The hydrophilicity or wettability of Sil-VOX n was observed by measuring the contact angle (59.9°). The chromatographic results were compared with those obtained with a conventional HILIC silica column. The Sil-VOX n phase showed much better separation of polar test analytes than the silica column, and the elution order was different. Differences in selectivity between these two columns indicate that the stationary phase cannot function merely as an inert support for a water layer into which the solutes are partitioned from the bulk mobile phase. To elucidate the interaction mechanism, the separation of dihydroxybenzene isomers was performed on both columns in normal-phase liquid chromatography. Sil-VOX n was very sensitive to the dipole moments of the positional isomers of polycyclic aromatic compounds in normal-phase liquid chromatography. The interaction mechanism for Sil-VOX n in HILIC separation is also described. Figure
Separation of nucleosides and nucleobases with Sil-VOXn (bottom) and a commercial silica column (top). Mobile phase of acetonitrile and 20 mM ammonium acetate (9:1, v/v). Flow rate 1 ml min-1, column temperature 25 °C. The analytes were as follows 5-iodouracil (1), thymine (2), uracil (3), 4,6-diaminopyrimidine (4), uridine (5), adenosine 2 (6), cytosine (7), cytidine (8), and guanosine (9) 相似文献
72.
F. Rahaman Peter K. F. Kuhfittig K. Chakraborty M. Kalam D. Hossain 《International Journal of Theoretical Physics》2011,50(9):2655-2665
This paper discusses a new model for galactic dark matter by combining an anisotropic pressure field corresponding to normal
matter and a quintessence dark energy field having a characteristic parameter ω
q
such that
-1 < wq < -\frac13-1<\omega_{q}< -\frac{1}{3}. Stable stellar orbits together with an attractive gravity exist only if ω
q
is extremely close to
-\frac13-\frac{1}{3}, a result consistent with the special case studied by Guzman et al. (Rev. Mex. Fis. 49:303, 2003). Less exceptional forms of quintessence dark energy do not yield the desired stable orbits and are therefore unsuitable
for modeling dark matter. 相似文献
73.
YSr2Fe3O8 − δ was prepared by traditional solid state reaction method and characterized by X-ray diffraction, ac impedance, dc conductivity, dilatometry and thermogravimetric analysis for possible use in solid oxide fuel cells (SOFCs). YSr2Fe3O8 − δ crystallizes with tetragonal symmetry in the space group P4/mmm and found to be stable at high temperatures under H2 and air. Four probe dc electrical conductivity measurements show that the conductivity increases up to 745 K and then decreases with temperature; the highest conductivity σ745K = 43.5 S cm− 1. The n-type conductivity at low oxygen partial pressure (pO2) changes to p-type at high pO2. Polarization behavior was investigated measuring the ac impedance response in symmetrical cell arrangements in air with YSZ and GDC electrolytes. Cathodic area specific resistance (ASR) varies with firing temperature. The lowest area specific resistance was observed with a GDC electrolyte fired at 1000 °C. In case of YSZ, ASR increases and in case of GDC, ASR decreases in air when electrode firing temperature decreases. At 800 °C ASRs are 0.20 Ω cm2 and 0.65 Ω cm2 with GDC and YSZ electrolytes, respectively, in air. Fuel cell measurements with symmetrical electrodes were performed using a thin YSZ electrolyte under H2 at anode and air at cathode, show that the power density is about 0.035 W/cm2 at 900 °C. 相似文献
74.
Mehedi Kalam Nur Farhad Sk. Monowar Hossein 《International Journal of Theoretical Physics》2014,53(1):339-349
The behavior of the timelike and null geodesics of charged E. Ayón-Beato and A. Garcia (ABG) black hole are investigated. For circular and radial geodesics, we investigate all the possible motions by plotting the effective potentials for different parameters. In conclusion, we have shown that there is no phenomenon of superradiance in this case. 相似文献
75.
Classical results on the expansion of complex functions in a series of special polynomials (namely inverse similar sets of polynomials) are extended to the Clifford setting. This expansion is shown to be valid in closed balls. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
76.
Mubasher Jamil Farook Rahaman Mehedi Kalam 《The European Physical Journal C - Particles and Fields》2009,60(1):149-156
The standard model of cosmology is investigated using a time-dependent cosmological constant Λ and Newton gravitational constant G. The total energy content is described by the modified Chaplygin gas equation of state. It is found that the time-dependent
constants coupled with the modified Chaplygin gas interpolate between the earlier matter to the later dark-energy dominated
phase of the universe. We also achieve a convergence of the parameter ω→−1, almost at the present time. Thus our model fairly alleviates the cosmic-coincidence problem, which demands ω=−1 at the present time. 相似文献
77.
M. Abul Bashar Keith W. Hipel D. Marc Kilgour Amer Obeidi 《Fuzzy Optimization and Decision Making》2018,17(3):287-315
A new analysis technique, appropriate to situations of high preference uncertainty, is added to the graph model for conflict resolution methodology. Interval fuzzy stabilities are now formulated, based on decision makers’ (DMs’) interval fuzzy preferences over feasible scenarios or states in a conflict. Interval fuzzy stability notions enhance the applicability of the graph model, and generalize its crisp and fuzzy preference-based stability ideas. A graph model is both a formal representation and an analysis procedure for multiple participant-multiple objective decisions that employs stability concepts representing various forms of human behavior under conflict. Defined based on a type-2 fuzzy logic, an interval fuzzy preference for one state over another is represented by a subinterval of [0, 1] indicating an interval-valued preference degree for the first state over the second. The interval fuzzy stabilities put forward in this research are interval fuzzy Nash stability, interval fuzzy general metarational stability, interval fuzzy symmetric metarational stability, and interval fuzzy sequential stability. A state is interval fuzzy stable for a DM if moving to any other state is not adequately desirable to the DM; where adequacy is measured by the interval fuzzy satisficing threshold of the DM and farsightedness, involving possible moves and countermoves by DMs, is determined by the interval fuzzy stability notion selected. Note that infinitely many degrees in an interval-valued preference are preserved in characterizing the desirability of a move. A state from which no DM can move to any sufficiently desirable scenario is an interval fuzzy equilibrium, and is interpreted as a possible resolution of the strategic conflict under study. The new stability concept is illustrated through its application to an environmental conflict that took place in Elmira, Ontario, Canada. Insightful results are identified and discussed. 相似文献
78.
A general formula (based on the method of variation of parameters) has been presented for determining an approximate solution of an nth order n=2,3,… weakly non-linear differential system with several damping effects. The general solution covers the under-damped, undamped and over-damped cases. The formulation as well as determination of the solution is simple. The method is illustrated by several examples. 相似文献
79.
Direct observation of a transition of a surface plasmon resonance from a photonic crystal effect 总被引:1,自引:0,他引:1
Transition of surface-plasmon resonance from out-of-plane photonic crystal effect is observed in a semiconductor array of subwavelength holes by optical pump-terahertz probe measurements. The dielectric properties of the photoexcited array are essentially altered by the intense optical excitation due to photogenerated free carriers. As a result, the array becomes metallic and favors the coupling and propagation of surface plasmons. The photoinduced resonant extremes agree well with the Fano model. 相似文献
80.
Amna Saeed Syeda Abida Ejaz Muhammad Sarfraz Nissren Tamam Farhan Siddique Naheed Riaz Faizan Abul Qais Samir Chtita Jamshed Iqbal 《Molecules (Basel, Switzerland)》2022,27(13)
Both members of the aldo-keto reductases (AKRs) family, AKR1B1 and AKR1B10, are over-expressed in various type of cancer, making them potential targets for inflammation-mediated cancers such as colon, lung, breast, and prostate cancers. This is the first comprehensive study which focused on the identification of phenylcarbamoylazinane-1, 2,4-triazole amides (7a–o) as the inhibitors of aldo-keto reductases (AKR1B1, AKR1B10) via detailed computational analysis. Firstly, the stability and reactivity of compounds were determined by using the Guassian09 programme in which the density functional theory (DFT) calculations were performed by using the B3LYP/SVP level. Among all the derivatives, the 7d, 7e, 7f, 7h, 7j, 7k, and 7m were found chemically reactive. Then the binding interactions of the optimized compounds within the active pocket of the selected targets were carried out by using molecular docking software: AutoDock tools and Molecular operation environment (MOE) software, and during analysis, the Autodock (academic software) results were found to be reproducible, suggesting this software is best over the MOE (commercial software). The results were found in correlation with the DFT results, suggesting 7d as the best inhibitor of AKR1B1 with the energy value of −49.40 kJ/mol and 7f as the best inhibitor of AKR1B10 with the energy value of −52.84 kJ/mol. The other potent compounds also showed comparable binding energies. The best inhibitors of both targets were validated by the molecular dynamics simulation studies where the root mean square value of <2 along with the other physicochemical properties, hydrogen bond interactions, and binding energies were observed. Furthermore, the anticancer potential of the potent compounds was confirmed by cell viability (MTT) assay. The studied compounds fall into the category of drug-like properties and also supported by physicochemical and pharmacological ADMET properties. It can be suggested that the further synthesis of derivatives of 7d and 7f may lead to the potential drug-like molecules for the treatment of colon cancer associated with the aberrant expression of either AKR1B1 or AKR1B10 and other associated malignancies. 相似文献