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141.
142.
基于模式/模群复用的多模光纤通信系统是目前光通信领域的研究热点。系统中存在多个模式/模群,如何准确识别它们是提升传输系统性能的关键问题之一。提出了一种基于深度学习的多模光纤模式与模群的智能识别模型,通过引入全卷积神经网络(CNN),对噪声影响情况下线偏振模式及其模群进行仿真和实验研究。首先,基于多平面光转换模式复用器件和普通OM2多模光纤,搭建10个模式(LP01、LP11a/b、LP21a/b、LP02、LP12a/b、LP31a/b)及其对应的3个模群的光场信息获取的仿真和实验平台,利用大量数据进行训练和验证。实验结果显示,模式/模群的总体识别率可达到100%。通过将获取的模群光场图片重构为低分辨率图片,研究低密度光电探测器阵列接收条件下,智能识别模型的识别性能。实验结果显示,采取4×4光探测器阵列接收光场信息时,能获得98.3%的识别效率。本研究表明提出的智能识别模型具有良好的光纤模式/模群智能识别能力,其在多模光纤通信系统性能提升与智能光性能监测方面具有一定的应用潜力。 相似文献
143.
Zhijun Wang Baozhu YangPanlai Li Zhiping Yang Qinglin Guo 《Physica B: Condensed Matter》2012,407(8):1282-1286
A yellow phosphor, Sr3SiO5:Eu2+, was synthesized by a high temperature solid-state method. Sr3SiO5:Eu2+ exhibits a single yellow emission under the blue radiation excitation. However, Sr3SiO5:Eu2+ shows a two-peak emission under the ultraviolet radiation excitation when Eu2+ doping content is less than 0.01 mol. Moreover, the blue emission disappears and the yellow emission reaches the peak value when Eu2+ doping content is 0.01 mol. Namely, the energy transfer takes place between the Eu2+ activators, which is located at two different crystallographic sites in the Sr3SiO5. And the energy transfer mechanism is the dipole-dipole interaction. 相似文献
144.
Chenxing YangTingyu Liu Zhijun ChengHaixiu Gan Jianyu Chen 《Physica B: Condensed Matter》2012,407(5):844-848
The defect formation energies and electronic structures of Mn doped strontium titanate have been studied using CRYSTAL-09 code. The defect formation energies for MnSr and MnTi, under different chemical potential conditions, have been obtained to determine the way Mn prefers to occupy in the Mn doped SrTiO3 crystal. From the electronic structures of Mn doped SrTiO3, it is shown that MnSr cannot change the band gap of SrTiO3. However, MnTi can effectively reduce the band gap of SrTiO3 and improve the photocatalysis. 相似文献
145.
Qian Q Huang Z Zhang X Yuan G 《Langmuir : the ACS journal of surfaces and colloids》2012,28(1):736-740
Microemulsions are often used in the synthesis of nanoparticles in solution. In this work, we put forward the concept of a "hard microemulsion", which is based on the differential partitioning of water and ethanol solvent molecules inside functional polymer matrices. When the mixture of water and organic solvent enters the functional polymer, the liquid molecules should partition to different regions. Water should concentrate in the microdomains rich in hydrophilic functional groups, forming water-enriched cores, whereas organic solvents should localize near the alkyl polymer skeleton, forming organic liquid enriched outer layers. From a macroscopic view, the swollen polymer matrix is divided into numerous "microdroplets", resembling frozen water-in-oil microemulsions. We define such a structure as a "hard microemulsion". The water-enriched microdroplets may act as templates for synthesizing inorganic nanoparticles. We demonstrate the utility of hard microemulsions for the controllable synthesis of silver and platinum nanoparticles inside different macroreticular functional polymers. 相似文献
146.
Membrane proteins are of particular biological and pharmaceutical importance, and computational modeling and structure prediction
approaches play an important role in studies of membrane proteins. Developing an accurate model quality assessment program
is of significance to the structure prediction of membrane proteins. Few such programs are proposed that can be applied to
a broad range of membrane protein classes and perform with high accuracy. We developed a new model scoring function Interaction-based
Quality assessment (IQ), based on the analysis of four types of inter-residue interactions within the transmembrane domains
of helical membrane proteins. This function was tested using three high-quality model sets: all 206 models of GPCR Dock 2008,
all 284 models of GPCR Dock 2010, and all 92 helical membrane protein models of the HOMEP set. For all three sets, the scoring
function can select the native structures among all of the models with the success rates of 93, 85, and 100% respectively.
For comparison, these three model sets were also adopted for a recently published model assessment program for membrane protein
structures, ProQM, which gave the success rates of 85, 79, and 92% separately. These results suggested that IQ outperforms
ProQM when only the transmembrane regions of the models are considered. This scoring function should be useful for the computational
modeling of membrane proteins. 相似文献
147.
BaZn2(PO4)2:Sm3+ phosphor was synthesized by a high temperature solid-state reaction in atmosphere. BaZn2(PO4)2:Sm3+ phosphor can be efficiently excited by ultraviolet and blue light, and the emission spectrum consists of three emission peaks at 568, 606 and 660 nm. By increasing the Sm3+ doped content, the emission intensity of the phosphor can reach the maximum at 0.02 mol Sm3+, then the concentration quenching occurs. By introducing the compensator charge R+ (R=Li, Na, K) into the BaZn2(PO4)2:Sm3+ phosphor, its emission intensity can be enhanced. The Commission International de l'Eclairage (CIE) chromaticity coordinates of Ba0.96Zn2(PO4)2:0.02Sm3+, 0.02K+ phosphor were (x=0.623, y=0.361). The results indicate that BaZn2(PO4)2:Sm3+, R+ (R=Li, Na, K) may be a promising red phosphor for white light-emitting diodes. 相似文献
148.
An evaporative light scattering detection (ELSD) based high-performance liquid chromatography (HPLC) method is developed for the determination of polysorbate 80 (tween 80) in therapeutic protein formulations. The method is simple and overcomes the difficulties associated with specificity and sensitivity. The method is suitable for the quantitation of polysorbate 80 in the usual formulation range (0.01-0.1%) as well as in trace amounts ≥13 μg/mL. The analysis is based on the removal of protein first by solid-phase extraction using Oasis HLB cartridges followed by HPLC analysis using Inertsil ODS-3 C 18 column (4.6×150 mm, 5 μm) using reversed-phase conditions. The detector response changes exponentially with an increase in polysorbate concentration. A very good linear fit of log ELSD response against log polysorbate 80 concentration is observed. The specificity, sensitivity, precision, and accuracy of the method are suitable for the quantitation of polysorbate 80 in protein formulations. 相似文献
149.
Hao Zhang Nianchen Zhou Xing Zhu Xinrong Chen Zhengbiao Zhang Wei Zhang Jian Zhu Zhijun Hu Xiulin Zhu 《Macromolecular rapid communications》2012,33(21):1845-1851
Well‐defined cyclic‐polymers (cyclic‐PAzoMMAs), bearing side‐chain phenylazo naphthalene chromophore, were successfully synthesized by the combination of atom transfer radical polymerization (ATRP) and copper(I)‐catalyzed azide/alkyne cycloaddition “click” reaction, as verified by GPC, 1H NMR, FTIR, and MALDI‐TOF mass spectrometry. The cyclic‐PAzoMMA showed higher glass transition temperatures than the linear‐PAzoMMA with the same molecular weight. Interestingly, the cyclic‐PAzoMMA exhibited deeper modulation depth (M.D.) induced by SRG, larger value of the photoinduced birefringence, increased fluorescence emission, and longer fluorescence lifetime in comparison with its linear counterpart. 相似文献
150.
Keliang Shi Fuqiang Liu Yuanlv Ye Zhijun Guo Wangsuo Wu 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(3):1277-1283
Metal ions sorption can be significantly affected by the presence of other sorbates, especially of complexing ligands. In
this study, the effect of Se(IV) on Eu(III) sorption onto TiO2 at different pH and Eu(III) concentration was investigated. Se(IV) was found to enhance Eu(III) sorption as a function of
Se(IV) concentration. Constant capacitance model was successfully used to interpret the sorption experimental data. The solubility
product of Eu2(SeO3)3 at ambient temperature was investigated to highlight the sorption mechanism of ternary sorption system. The pK
sp value of Eu2(SeO3)3 was found to be 31.51 ± 0.95. 相似文献