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1.
Jiangen Huang Guiqin Zhang Yuanhe Huang Decai Fang Deqing Zhang 《Journal of magnetism and magnetic materials》2006
A one-dimensional (1D) silver (I) complex of nitronyl nitroxide with fairly strong antiferromagnetic interaction, in which the metal ions are diamagnetic, is investigated by means of the ab initio crystal orbital method based on the density functional theory. The calculated values of the magnetic coupling constant (J) are close to the experimental measured J value in the periodic system. The magneto-structural correlation reveals that the existence of an antiferromagnetic coupling pathway along nitronyl nitroxide units via silver (I) ion in this system. The spin population distribution also shows the existence of spin delocalization along the ONCNO–Ag–ONCNO, which affords a rational interpretation for the antiferromagnetic interaction mechanism. 相似文献
2.
Using the polyglycol gel method, a series of Pr2 − x
SrxCoO4 ± y
(0.2 ≤ x ≤ 1.0) mixed oxides were prepared, and their catalytic activities were studied in the test reaction of NO reduction by CO.
The solid-state physicochemical properties, including crystal structure, defect structure, IR spectrum, valence state of B-site
ions, nonstoichiometry oxygen (y), oxygen species, and redox properties, were characterized by means of XRD, IR, TPD, TPR,
XPS, and chemical analysis. The results show that all mixed oxides display a K2NiF4 structure. When x = 0.2 and 1.0, the obtained samples still have little uncertain mixed oxides; however, the mixed oxides (x = 0.4, 0.6, 0.8) all represent a single A2BO4 phase. With the increase of x, lattice parameters, unit-cell volume, and average crystalline size decrease gradually, whereas microstrain density, the
concentration of Co3+, the amounts of lattice oxygen released and the concentration of oxygen vacancy increase. The catalytic activities of Pr2 − x
SrxCoO4 ± y
catalysts for NO reduction by CO are closely correlated with oxygen vacancy and the concentration of Co3+.
Published in Russian in Kinetika i Kataliz, 2006, Vol. 47, No. 3, pp. 431–437.
The text was submitted by the authors in English. 相似文献
3.
使用SAC/SAC-CI和D95++, 6-311++g, 6-311++g**及D95(d)基组, 分别对BF分子的基态X1Σ+、第一简并激发态A1Π和第二激发态B1Σ+的平衡结构和谐振频率进行优化计算. 对所有计算结果进行比较, 得出6-311++g**基组为最优基组. 运用6-311++g**基组和SAC方法对基态X1Σ+, SAC-CI方法对激发态A1Π和B1Σ+进行单点能扫描计算, 并用正规方程组拟合Murrell-Sorbie函数, 得到相应电子态的势能函数解析式, 由得到的势能函数计算了与X1Σ+, A1Π和B1Σ+态相对应的光谱常数, 结果与实验数据较为一致. 相似文献
4.
在反相和正相色谱模式下,研究了几种嘌呤衍生物在葫芦[6]脲单轮烷键合硅胶固定相上的高效液相色谱行为,并在反相模式下与ODS固定相进行了比较,考察了流动相中甲醇含量、流动相pH值和离子强度对嘌呤化合物保留的影响。研究结果表明:在反相模式下,嘌呤化合物与葫芦[6]脲单轮烷键合相之间存在多种相互作用,除疏水作用外,分离过程中还存在与ODS不同的色谱分离机制。在正相条件下,多作用力的色谱分离机制同样存在。葫芦[6]脲单轮烷键合相与溶质之间存在疏水、氢键、π-π和偶极-偶极等多种作用力,协同作用提高了固定相对嘌呤化合物的分离选择性。 相似文献
5.
6.
Xiaochun Zhou Xiaojun Wang 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(13):2033-2036
A modified low temperature solid state process has been proposed to systematically synthesize europium-doped yttrium phosphate-vanadates with general formula Y0.48Li1.5V1 ? x P x O4:Eu3+ (x = 0.2, 0.4, 0.6). All the Y0.48Li1.5V1 ? x P x O4:Eu3+ products were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The excitation and emission spectra were measured at room temperature. Y0.48Li1.5V1 ? x P x O4:Eu3+ show the characteristic missions of Eu3+ (5 D 0?7 F 1, 2, 3, 4 transitions dominated by 5 D 0?7 F 2), intensities of the products were sensitive to the x value, and the x value had an obvious influence on the (5 D 0?7 F 2)/(5 D)0?7 F 1) intensity ratio of Eu3+. In addition, incorporation of Li+ ions in the phosphors reduce the amount of Y2O3, lower the cost of production, and cause a new phase Li3VO4. 相似文献
7.
8.
以烟酰胺和硝酸铕为原料,采用热溶剂法合成了烟酰胺-铕配合物的微纳米球。其结构和性能经红外光谱(IR)、热重(TG)、扫描电镜(SEM)、X-射线衍射(XRD)、元素分析(EDS)和荧光检测等表征。研究结果表明:配合物含有碳、氧、氮和铕等元素,其红外光谱图与烟酰胺配体有明显的差异;配合物的质量在250 ℃和550 ℃条件下出现了明显的下降,下降率分别为15%和19%; SEM照片显示配合物为大小不均一的微纳米球,且具有较好的荧光发光性能,发射峰位于579 nm, 591 nm, 612 nm, 618 nm, 693 nm和699 nm。烟酰胺配体和烟酰胺-铕配合物对腺癌人肺泡基底上皮细胞(A549细胞)的活性影响趋势一致,随着药物浓度升高,该细胞活性没有发生明显变化。 相似文献
9.
An unprecedented 4f-5d material(La6Hg5Br26)[4(HgBr2)](2Br)(1)was syn-thesized by hydrothermal reactions and structurally characterized by single-crystal X-ray diffraction method.Complex 1 crystallizes in the Pbam space group of orthorhombic system with a=13.0980(10),b=13.6650(9),c=28.010(2)?,V=5013.4(6)?^3,Br36Hg9La6,Mr=5515.53,Z=2,Dc=3.613 g/cm^3,μ(MoKα)=29.457 mm^–1 and F(000)=4598.Compound 1 is characteristic of a two-dimensional(2D)layered structure.The photoluminescent measurements with solid-state samples reveal that compound 1 has a strong emission in the green region of light spectrum.It has remarkable CIE chromaticity coordinates of(0.2499,0.3589).A wide optical band gap of 3.41 eV is discovered by the solid-state UV/vis diffuse reflectance spectrum.The variable-temperature magnetic susceptibility obeys the Curie-Weiss law(cm=c/(T–q))with C=2.48 K and a negative Weiss constantθ=–169.07 K as revealed by the magnetic measurements,indicating the existence of an antiferromagnetic interaction in compound 1. 相似文献
10.
合成了4个新的基于多胺酚配体的Dy(Ⅲ)和Zn/Ni-Dy(Ⅲ)配合物:[Dy(CH_3OCH3)L](1),[Dy2(μ-H2O)L2](2),[Zn2DyL2]ClO4·H2O(3)和[Ni2DyL2]ClO4·H2O (4)(H3L=N,N′,N″-三(3,5-二甲基-2-羟基苯酚)-1,4,7-三氮杂环壬烷)。X射线单晶衍射分析表明,配合物1和2分别为单核和双核Dy(Ⅲ)配合物,3和4为M-Dy(Ⅲ)-M三核配合物(M=Zn (3),Ni (4))。磁性测试表明,配合物1和2具有场诱导的慢磁弛豫行为,且2具有多个磁弛豫过程,配合物3和4中没有观察到明显的慢磁弛豫行为。荧光测试表明,配合物1~3具有Dy(Ⅲ)离子典型的窄带特征发射,由于Ni(Ⅱ)离子的荧光猝灭作用,配合物4没有明显的荧光产生。 相似文献