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131.
Taeyeon Kwon Jin Young Koo Hee Cheul Choi 《Angewandte Chemie (International ed. in English)》2020,59(38):16436-16439
Together with high conductivity, high flexibility is an important property required for next generation organic electronic components. Both properties are difficult to achieve together especially when the components are crystalline because of the intrinsic high brittleness of organic molecular crystals. We report an organic radical crystal system that has both high flexibility and high conductivity. The crystal consists of 9,10‐bis(phenylethynyl)anthracene radical cation ( BPEA.+ ) units, and shows flexibility under pressure with high conductivity in ambient condition exhibiting average conductivity of 2.68 S cm?1 when normal linear shape, as well as 2.43 S cm?1 when bent. The structural analysis reveals that both a short π–π distance (3.290 Å) between BPEA.+ units that are aligned along the crystal length direction, and the presence of PF6? counter ions induce flexibility and high electrical conductivity. 相似文献
132.
133.
J. Liu T.-C. Long P. H. Geil F. Rybnikar 《Journal of Polymer Science.Polymer Physics》1996,34(17):2843-2851
Single crystals of poly(terephthalic anhydride) (PTA) have been grown using the confined thin film melt polymerization technique. Thin lamellae (ca. 50 Å) are found for low polymerization temperatures, with thick crystals forming for polymerization at 200°C. Shearing of the material shortly after the initiation of polymerization at 200°C yielded single crystal domains composed of fibrillar texture material; these samples gave [010] zone ED patterns complementing the [001] zone patterns from the unsheared CTFMP samples. A monoclinic, single chain, two repeat unit, unit cell (Pc11) is proposed based on four different electron diffraction zone patterns: a = 6.01 Å, b = 3.945 Å, c = 14.11 Å, α = 106.9°. Simulations, using the Cerius2 program, of the corresponding molecular conformation, packing and electron diffraction (ED) patterns were performed; the ED simulations are in good agreement with the observed patterns. An R-factor of 0.23 is obtained based on a comparison of calculated and observed structure factors for the 39 independent ED reflections observed on the different zone patterns. © 1996 John Wiley & Sons, Inc. 相似文献
134.
A new series of sulfur-containing side-chain liquid crystalline polymer is described. Mesomorphic side chains with methylene spacers of different lengths have been synthesized, and their structures were identified by nuclear magnetic resonance, infrared and mass spectrometry. The liquid crystalline nature of the polymers was characterized by microscopy and differential scanning calorimetry. 相似文献
135.
甲壳素类液晶高分子研究--低分子量壳聚糖溶致液晶性及分子量对液晶临界浓度的影响 总被引:3,自引:0,他引:3
研究了两种用酶降解法得到的低分子量壳聚糖样品(CS1和CS2)的溶致液晶性.用GPC并辅以质谱法确定了两样品的数均相对分子质量为622和2311 g/mol.在相对分子质量低至622的低分子量壳聚糖(相当于四糖)水溶液中仍发现了溶致液晶现象,并确定出相对分子质量为622和2311的低分子量壳聚糖液晶临界浓度为73%和36%(W/W%),这些结果与已报道的中、高分子量壳聚糖液晶临界浓度随分子量升高而降低的基本规律是一致的.实验结果与经典的KS理论预测值不符,因为低分子量壳聚糖的相对分子质量超过了KS理论对高分子临界浓度的预测范围. 相似文献
136.
《Physics letters. A》2020,384(26):126678
We proposed an enhanced-performance relative humidity (%RH) nano-sensor based on MOF-801/TiO2 one-dimensional photonic crystals (1DPC). The maximum reflectance-peak wavelength of it shifted obviously in the range of 20%-90% under varying %RH levels, due to the highly moisture-sensitive MOF-801 film in the 1DPC structure. It was demonstrated that the linear spectrum sensitivity of the MOF-801/TiO2 %RH 1DPC sensor is exceeding 119 pm/%RH from 20%RH to 90% RH, and the sensitivity of reflection power variations exhibits 1.34 dB/%RH with the resolvable relative humidity variation less than 0.1%RH at 15°C. Meanwhile, the sensor shows a fast optical response time less than 100 ms with exceptional repeatability and reliability, which promises successful measurements of human respiration. Moreover, the sensor performance on the structure of 1DPC is investigated, representing a tradeoff between the sensing sensitivity and response time. 相似文献
137.
R. Asquini C. Chiccoli A. d’Alessandro P. Pasini C. Zannoni 《Molecular Crystals and Liquid Crystals》2019,683(1):46-55
AbstractWe present detailed Monte Carlo simulations of a simple model of a nematic liquid crystal slot waveguide shifter, investigating the effect of an applied electric external field. The simulations are based on the Lebwohl-Lasher lattice spin model with boundary conditions chosen to mimic the planar alignment as in Silicon Organic Hybrid waveguides and the homeotropic anchoring appropriate for Polydimethylsiloxane polymer walls. The external field is modeled by adding a term to the Hamiltonian which describes its coupling to the mesogenic molecules. We have investigated the effect of the external field on the optical transmission and the ordering across the cell. 相似文献
138.
Shady Nada Mohamed Hagar Omaima Farahat Ahmed A. Hasanein Abdul-Hamid Emwas Abeer Ali Sharfalddin Mariusz Jaremko Mohamed A. Zakaria 《Molecules (Basel, Switzerland)》2022,27(7)
Three rings 2-hydroxypyridine liquid crystalline compounds have been prepared and fully characterized. The mesomorphic behavior of the prepared compounds has been investigated in terms of differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Moreover, a comparative study between the prepared compounds and previously reported analogs has been discussed in terms of the orientation and position of the mesogenic core, in addition to the direction of the terminal alkyl chains. Furthermore, a detailed computational approach has been studied to illustrate the effect of geometrical and dimensional parameters on the type of the enhanced texture and the mesomorphic range and stability. The results of the DFT study revealed that the orientation of the mesogen could affect the mesomorphic behavior and this has been attributed in terms of the degree of the polarizability of the linking groups. This result has been confirmed by calculation of the net dipole moment and the molecular electrostatic potential that show how the mesogen orientation and position could impact the molecular charge separation. Finally, the effect of the pyridyl group has been also investigated in terms of the calculated aromaticity index and the π-π stacking. 相似文献
139.