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51.
Daniel F. Sunday Elizabeth Ashley Lei Wan Kanaiyalal C. Patel Ricardo Ruiz R. Joseph Kline 《Journal of Polymer Science.Polymer Physics》2015,53(8):595-603
Block copolymer directed self‐assembly (BCP) with chemical epitaxy is a promising lithographic solution for patterning features with critical dimensions under 20 nm. In this work, we study the extent to which lamellae‐forming poly(styrene‐b‐methyl methacrylate) can be directed with chemical contrast patterns when the pitch of the block copolymer is slightly compressed or stretched compared to the equilibrium pitch observed in unpatterned films. Critical dimension small angle X‐ray scattering complemented with SEM analysis was used to quantify the shape and roughness of the line/space features. It was found that the BCP was more lenient to pitch compression than to pitch stretching, tolerating at least 4.9% pitch compression, but only 2.5% pitch stretching before disrupting into dislocation or disclination defects. The more tolerant range of pitch compression is explained by considering the change in free energy with template mismatch, which suggests a larger penalty for pitch stretching than compressing. Additionally, the effect of width mismatch between chemical contrast pattern and BCP is considered for two different pattern transfer techniques. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 595–603 相似文献
52.
Exploiting natural abundance 13C–15N coupling as a method for identification of nitrogen heterocycles: practical use of the HCNMBC sequence 下载免费PDF全文
In this paper, we detail the results of 1H–15N correlation data obtained via 13C–15N coupling at natural abundance on a number of classes of azoles including pyrazoles, imidazoles and triazoles. The experiment produces data that is highly complementary to direct 1H–15N HMBC type correlations in that it can provide 15N chemical shift data for nitrogen that may not show up in the HMBC. This is particularly advantageous in the triazoles where 15N chemical shift can be diagnostic of regiochemistry. Because of the consistency in JCN values among the azoles, the experiment produces distinctive correlation patterns that can be used for identification of regiochemistry. The experiment can also be used to directly measure 13C–15N coupling constants. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
53.
A local interaction simulation approach (LISA) for the wave propagation in inhomogeneous 2D media is presented. The method is designed to take full advantage of massively parallel computing, such as provided by the Connection Machine. Crosspoints at the intersection of orthogonal interfaces separating media of different physical properties are treated in the framework of a sharp interface model. A comparison with finite difference techniques shows that the proposed method avoids the ambiguities due to the smoothing of the physical quantities, which is necessary in order to transform differential equations into finite difference equations. The smoothing procedure may cause severe numerical errors, when the variations of the physical properties across the interfaces are large.
In order to demonstrate the efficiency and reliability of the approach several examples of simulation of pulse propagation in different media are reported. 相似文献
54.
Yang Y Feng W Hu J Zou S Gao R Yamato K Kline M Cai Z Gao Y Wang Y Li Y Yang Y Yuan L Zeng XC Gong B 《Journal of the American Chemical Society》2011,133(46):18590-18593
Aromatic oligoamide macrocycles exhibit strong preference for highly directional association. Aggregation happens in both nonpolar and polar solvents but is weakened as solvent polarity increases. The strong, directional assembly is rationalized by the cooperative action of dipole-dipole and π-π stacking interactions, leading to long nanotubular assemblies that are confirmed by SEM, TEM, AFM, and XRD. The persistent nanotubular assemblies contain non-collapsible hydrophilic internal pores that mediate highly efficient ion transport observed with these macrocycles and serve as cylindrical sites for accommodating guests such as metal ions. 相似文献
55.
This paper gives one-term componentwise asymptotics for theM and spectral matrices of a self-adjoint realisation of aneven-order ordinary differential expression. The underlyinginterval is assumed to have at least one regular endpoint, andthe boundary conditions are supposed to be separated. Furthermore,the weight function and the reciprocal of the highest-ordercoefficient are supposed to be of regular variation at the regularendpoint, in the sense of Bingham, Goldie and Teugels. 1991Mathematics Subject Classification: 34B24, 34E05. 相似文献
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58.
Weihong Lin Ejiofor AD EzekweJr Zhen Zhao Emily R Liman Diego Restrepo 《BMC neuroscience》2008,9(1):114
Background
The main olfactory epithelium (MOE) in the nasal cavity detects a variety of air borne molecules that provide information regarding the presence of food, predators and other relevant social and environmental factors. Within the epithelium are ciliated sensory neurons, supporting cells, basal cells and microvillous cells, each of which is distinct in morphology and function. Arguably, the least understood, are the microvillous cells, a population of cells that are small in number and whose function is not known. We previously found that in a mouse strain in which the TRPM5 promoter drives expression of the green fluorescent protein (GFP), a population of ciliated olfactory sensory neurons (OSNs), as well as a population of cells displaying microvilli-like structures is labeled. Here we examined the morphology and immunocytochemical properties of these microvillous-like cells using immunocytochemical methods. 相似文献59.
Form factors for the electroexcitation of the + (1.27 MeV), + (2.23 MeV), and + (3.51 MeV) states in 31P have been measured for momentum transfers from 0.36 to 0.80 fm?1 at the NBS electron scattering facility. In addition, form factors for the 2.23 MeV state in the momentum transfer range 0.74 to 1.78 fm?1 have been extracted from data obtained in a previous experiment. Using the DUELS distorted-wave code the B(E2, ω) ↓ were found to be 6.0 ± 0.9, 6.9 ± 0.3, and 2.7 ± 0.3 W.u. for the 1.27, 2.23, and 3.51 MeV states, respectively. The form factors for these states, calculated using wave functions derived in an intermediate-coupling vibrational calculation, are compared with the data. 相似文献
60.
A. A. Kline T. N. Rogers M. E. Mullins B. C. Cornilsen Lj. M. Sokolov 《Journal of Sol-Gel Science and Technology》1994,2(1-3):269-272
Attenuated Total Reflectance (ATR) FTIR has been used to follow sol-gel synthesis kinetics for tetraethylorthosilicate (TEOS), ethanol, and water solutions yielding pure silicate materials. Aluminosilicates have also been made using TEOS:ethanol:water solutions doped with Al(III). Effective rate constants have been fitted to a kinetic model suggested by the literature for pure silicate materials. This model has been extended to include the effect of Al(III) on the rate constants. The effects of solution pH, temperature, and varying TEOS/Ethanol mole ratios have been investigated. Reliable effective rate constants for metal doped sol-gel solutions will lead to better control of the morphological and chemical properties of multi-component glass materials. 相似文献