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61.
Enhanced nonlinearity in photonic crystal fiber by germanium doping in the core region 总被引:2,自引:0,他引:2
Germanium doping in silica can be used as a method for nonlinearity enhancement.Properties of the enhanced nonlinearity in photonic crystal fiber(PCF)with a GeO2-doped core are investigated theoretically by using all-vector finite element method.Numerical result shows that the nonlinear coefficient of PCF is greatly enhanced with increasing doping concentration,furthermore,optimal radius of the doped region should be considered for the desired operating wavelength. 相似文献
62.
《Journal of Coordination Chemistry》2012,65(20):3541-3550
To further explore the coordination possibilities of naphthalene-based carboxylic acids, a ZnII coordination polymer, [Zn3(L)6(bipy)2] n (1), with bulky 2-naphthol-5-carboxylate (L) and bridging 4,4′-bipyridine (bipy), was synthesized and characterized. Structural analysis reveals that 1 is a 1-D polymeric chain with trinuclear units as nodes, which are further extended via interchain secondary interactions, such as O–H ··· O hydrogen-bonding and aromatic π ··· π stacking interactions, to form an overall 3-D framework. Complex 1 exhibits strong solid-state luminescence emission at room temperature, mainly originating from intraligand π→π* transition of L. 相似文献
63.
64.
基于时域有限差分法,以半导体材料CdSe和CdTe构成二维三角晶格光子晶体,数值模拟了它们的光子晶体能态密度电磁场特性。结果表明,CdSe和CdTe构成二维三角晶格光子晶体具有较好的光子带隙,形成的带隙宽度随介电常数差值的增大而增大。研究结果为光子晶体器件的开发提供参考。 相似文献
65.
报道用一步酸化法制得四种未见报道的1:10系列镧系钼钒杂多配合物K7H8LnMo4V6P36.xH2O(Ln=La,Ce,Pr,Nd)。提示元素分析,红外光谱,紫外光谱,X射线粉末衍射及差热-热重分析结果讨论了它们的结构及性质。 相似文献
66.
Two kinds of aliphatic alternating polyesteramide prepolymers were prepared through melt polycondensation from N,N’-bis(2-hydroxyethyl)-adipamide and adipic acid or sebacic acid. Chain extension of them was conducted with 2,2′-(1,4-phenylene)-bis(2-oxazoline) and adipoyl biscaprolactamate as combined chain extenders. The chain extended polyesteramides (ExtPEAs) were characterized by IR, 1 H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide angle X-ray scattering, tensile test and enzymatic degradation. The results showed that the ExtPEA(4,m)s were mainly constituted with the diester adipamide alternating units. ExtPEA(4,4) and ExtPEA(4,8) had Tm of 83.8℃ and 85.8℃ and initial decomposition temperature above 310.0℃. They crystallized similarly as Nylon-66 did and were flexible thermoplastic materials with tensile strength up to 25.64 MPa and strain at break up to 737%. 相似文献
67.
《高分子科学杂志,A辑:纯化学与应用化学》2013,50(7):785-806
The solid state postcure reaction mechanism of polyurethane elastomers (PU) synthesized using a relatively small excess (up to 10%) of isocyanate was studied. The postcure process succeeds especially with the assistance of atmospheric humidity and, its process velocity depends on PU sample thickness. The polymer network is consolidated mainly by the formation of a new urea group. The formation of allophanate, uretidinedione, and isocyanurate groups and possible reticulations by the intermediary amine groups formed, play only a secondary role in the studied conditions. Kinetic equations regarding the postcure evolution were followed by means of the changes in mechanical properties. The evolution of the process was correlated to different kinetic measurements regarding the elementary processes involved like the consumption of NCO groups, absorption of water from the atmospheric humidity, and desorption of CO2 resulted during the formation of urea group. The CO2 desorption appears to be the slowest dynamic process. 相似文献
68.
Idris Zembouai Mustapha Kaci Stéphane Bruzaud Aida Benhamida Yves-Marie Corre Yves Grohens 《Polymer Testing》2013,32(5):842-851
The paper aims to study blend properties of biodegradable polymers of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and polylactide (PLA) prepared by melt mixing. Blend compositions based on PHBV/PLA were investigated according to the following weight ratios, i.e. 100/0, 75/25, 50/50, 25/75 and 0/100 wt%. The study showed through scanning electron microscopy (SEM) that blends of PHBV/PLA are not miscible. This is consistent with differential scanning calorimetry (DSC) data which indicate the presence of two distinct glass transition temperatures (Tg) and melting temperatures (Tm), attributed to the neat polymers, over all the range of blend compositions. Water and oxygen barrier properties of PHBV/PLA blends are significantly improved with increasing the PHBV content in the blend. Further, morphological analyzes indicated that increasing the PHBV content in the polymer blends results in increasing the PLA crystallinity due to the finely dispersed PHBV crystals acting as a filler and a nucleating agent for PLA. On the other hand, the addition of PLA to the blend results in a very impressive increase in the complex viscosity of PHBV. Moreover, the rheological data showed that, excluding the specific behavior of the neat polymers at low frequencies, i.e. less than 0.1 Hz, the complex viscosity of PHBV/PLA blends fits the mixing law well. 相似文献
69.
Liu JM Yang TL Liang XS Wu AH Li LD Lin SQ 《Analytical and bioanalytical chemistry》2004,380(4):632-636
Luminescent 50-nm silicon dioxide nanoparticles containing both types of rhodamine 6G (R; particles denoted R-SiO2) were synthesized by the sol–gel method. In the presence of Pb(Ac)2 as a heavy atom perturber the particle can emit the intense and stable room-temperature phosphorescence (RTP) signal of R on a polyamide membrane, with exmax/emmax=470/635 nm for R. Our research indicates that the specific immune reaction between goat-anti-human IgG antibody labeled with R-SiO2 and human IgG can be carried out quantitatively on a polyamide membrane, and the phosphorescence intensity was enhanced after the immunoreaction. Thus a new method for solid-substrate room-temperature phosphorescence immunoassay (SS-RTP-IA) for determination of human IgG was established on the basis of antibody labeled with the nanoparticles containing binary luminescent molecules. The linear range of this method is 0.0624–20.0 pg spot–1 of human IgG (corresponding to a concentration range of 0.156–50.0 ng mL–1, sample volume 0.40 L spot–1). The regression equations of the working curves are Ip=71.27+7.208mIgG (pg spot–1) (r=0.9996). Detection limits calculated as 3Sb/k are 0.022 pg spot–1. Compared with the same IA using fluorescein isothiocyanate (FITC) as the marker the new method was more sensitive and had a wider linear range. After elevenfold replicate measurement RSD are 4.5 and 3.6% for samples containing 0.156 and 50.0 ng mL–1 IgG, respectively. This method is sensitive, accurate, and of high precision. 相似文献
70.
采用熔盐法合成了YVO4∶Sm3+红色发光材料. 用X射线粉末衍射对其结构进行表征, 证实样品为具有锆石结构的YVO4相; 测定了样品的激发与发射光谱; 分析了不同的掺杂浓度和烧结温度对样品发光强度的影响. 研究结果表明, 采用熔盐法合成的样品均可以产生Sm3+的特征发射, 但是与其它方法相比, 熔盐法合成样品位于647 nm处Sm3+的4G5/2-6H9/2发射明显得到加强, 从而使得样品发出明亮的红光, 而不是其它合成方法获得的橙色光. 当掺杂浓度为1%(摩尔分数)且在500 ℃下烧结5 h后, 熔盐法得到的YVO4∶Sm3+荧光粉的发光强度最大. 相似文献