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991.
Rapid crystallization and morphological adjustment of zeolite ZSM-5 in nonionic emulsions 总被引:1,自引:0,他引:1
Zeolite ZSM-5 was synthesized for the first time in a nonionic emulsion composed of polyoxyethylated alkylphenol, butanol, cyclohexane and tetraethylammonium hydroxide (TEAOH)-containing zeolite synthesis mixture. The crystallization kinetics in the emulsion was investigated and the ZSM-5 product was characterized in detail by XRD, SEM, FT-IR, TG, N2 adsorption and CHN analysis techniques. Compared with the conventionally hydrothermal synthesis with the same structure directing agent TEAOH, the emulsion system allows rapid crystallization of ZSM-5. The ZSM-5 product exhibits unusual agglomerated structure and possesses larger specific surface area. The FT-IR, TG results plus CHN analysis show the encapsulation of a trace of emulsion components in the emulsion ZSM-5. Control experiments show the emulsion system exerts the crystallization induction and morphological adjustment effects mainly during the aging period. The effects are tentatively attributed to the confined space domains, surfactant-water interaction as well as surfactant-growing crystals interaction existing in the emulsion. 相似文献
992.
Yong Suk Choi Jong-Yun Kim Suk Bon Yoon Kyuseok Song Young Jin Kim 《Microchemical Journal》2011,99(2):332-338
A wavelength-dispersive X-ray fluorescence (WDXRF) technique that uses the scattered radiation of the X-ray tube lines and the fluorescence radiation of an element present in a powder sample is proposed as a non-destructive method for the determination of the water content in silica powder. Although direct X-ray fluorescence analysis of water using WDXRF is not adequate for the quantitative determination of water in powder, due to the very low fluorescence yield for hydrogen and oxygen, the fluorescence signal of silicon (Si) in silica powder is attenuated by water, and is shown to decrease in proportion to the water content in silica powder. In addition, it is demonstrated that the Compton- and Rayleigh-scattering of the X-ray tube lines is proportional to the water content. The coefficients of determination, R2, of the linear regression equations obtained from the calibration curves for all individual scattered radiations and for the fluorescence radiation of Si were > 0.90. The sum of the peak intensities of the four scattering signals, i.e. the Rayleigh-scattered Rh K–L2,3 and Rh K–M2,3 lines, and Compton-scattered Rh K–L2,3 and Rh K–M2,3 lines, also showed fairly good linearity and sensitivity over a very wide range of water content from 0 wt.% to 61.5 wt.%. However, porosity had a significant effect on the X-ray signal at low water content, in the range from 0 wt.% to 7.5 wt.%, where the sensitivity for the silica nanopowder with well-defined mesopores (~ 3 nm in diameter) decreased to 0.40 kcps/wt.%, from 0.99 kcps/wt.% for the non-porous silica nanopowder. The use of the Si fluorescence signal along with the scattered radiation of the X-ray tube lines expands the applicability of conventional XRF spectrometers to the quantitative determination of water content in silica powder. 相似文献
993.
A CuI-catalyzed Suzuki cross-coupling reaction of organoboron derivatives with alkynyl bromides has been developed. In the presence of CuI (10 mol %) and 8-hydroxyquinoline (20 mol %), organoboron derivatives including aromatic and alkenyl boronic acids, potassium aryltrifluoroborates, and sodium tetraphenylborate reacted smoothly with 1-bromo-2-substituted acetylene to generate the corresponding cross-coupling products in good to excellent yields in C2H5OH. It is important to note that aromatic N,O-ligand 8-hydroxyquinoline is the most effective ligand for the reaction. 相似文献
994.
Paul W. Wang Jin‐Cherng Hsu Yung‐Hsin Lin Huang‐Lu Chen 《Surface and interface analysis : SIA》2011,43(7):1089-1094
Aluminum oxynitride films were deposited by ion beam sputtering technique at room temperature. The optical properties and morphologies of the aluminum oxynitride films were studied and reported previously. It was found that the optical properties are closely related to the O contents in the films. In this study, the structures of the films were investigated by X‐ray diffractometer and XPS. Three oxidation states of N1s in oxynitride films, N+, N2+ and N3+, were clearly deduced from N1s spectra in the amorphous films fabricated under various oxygen partial pressures (PO2). To our knowledge, three oxidation states of N1s have not been simultaneously observed and reported in the aluminum oxynitride films previously. Corresponding bonding variations in Al2p and O1s spectra indicated more oxygen in oxynitride in the film as PO2 increases. Three aluminum oxynitride networks, AlO2N, AlO2.5N and AlO3N were deduced. Optical properties of aluminum oxynitride films resemble those of AlN and Al2O3 films when PO2 is low and high during the deposition. The refractive indices and extinction coefficients of the aluminum oxynitride films can be adjusted by using proper PO2 during the film depositions. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
995.
Liqiang Tan Yeling Jin Xiaochun Cheng Jie Wu Wei Zhou Liangdong Feng 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(3):575-585
Batch sorption experiments were performed to remove Eu(III) ions from aqueous solutions by using attapulgite under ambient
conditions. Different experimental conditions, such as contact time, solid content, foreign ions, pH, ionic strength, fulvic
acid and temperature, have been investigated to study their effect on the sorption property. The results indicated that the
sorption of Eu(III) onto attapulgite was strongly dependent on pH, ionic strength and temperature. The sorption increased
from about 8.9 to 90% at pH ranging from 2 to 6 in 0.01 mol/L NaNO3 solution. The Eu(III) kinetic sorption on attapulgite was fitted by the pseudo-second-order model better than by the pseudo-first-order
model. The sorption of Eu(III) onto attapulgite increased with increasing temperature and decreasing ionic strength. The Langmuir
and Freundlich models were used to simulate the sorption isotherms, and the results indicated that the Freundlich model simulated
the data better than the Langmuir model. The thermodynamic parameters (∆G
o, ∆S
o, ∆H
o) were determined from the temperature dependent isotherms at 298.15, 318.15 and 338.15 K, and the results indicated that
the sorption reaction was an endothermic and spontaneous process. The results suggest that the attapulgite is a suitable material
as an adsorbent for preconcentration and immobilization of Eu(III) from aqueous solutions. 相似文献
996.
采用密度泛函理论和含时密度泛函理论方法计算了2个吩噻嗪类染料及其吸附到TiO2上后分子的基态和激发态光物理性质与热力学参数.结果表明,电子给体的改变虽未明显改变染料的光谱性质(垂直跃迁能和振子强度),但可以改变分子的前线轨道能级,进而影响染料分子的激子结合能Eb及激发态电子注入到半导体TiO2中的驱动力△Gint的大小... 相似文献
997.
两段式固定床富氧-水蒸气气化实验研究 总被引:2,自引:0,他引:2
两段式固定床富氧-水蒸气气化实验研究 《燃料化学学报》2011,39(8):595-599
以玉米芯颗粒为原料在两段式固定床气化装置上进行了气化实验,考察了当量比ER、富氧浓度OC和水蒸气配比S/B对气化温度、气化气组分、低位热值、气体产率、气化效率和碳转化率等参数的影响,并比较了两段式固定床与传统下吸式固定床的气化特性。实验结果表明,当量比为0.27时H2的体积分数、CO的体积分数和气化效率达到最大值;增加富氧浓度能优化气化效果,但富氧浓度大于90%后,燃气质量和气化效率均提高不大;增加S/B能提高H2的体积分数,但同时会降低CO的体积分数、气体热值、气化效率;当S/B为0.6时,氢气的体积分数达最高值33.3%,H2/CO比为1.32;相比于传统固定床,两段式固定床气化可明显提高气化温度、氢气的体积分数、碳转化率和气化效率,降低焦油含量。 相似文献
998.
Hyun Min ParkByul Nim Oh Jin Hoon KimWu Qiong In Hong HwangKwang-Deog Jung Cheal Kim Jinheung Kim 《Tetrahedron letters》2011,52(43):5581-5584
In this study, an assay to quantify the presence of aluminum ions with a receptor containing naphthol and quinoline moieties was developed using a turn-on fluorescence enhancement approach. Upon treatment with aluminum ions, the fluorescence of the receptor was enhanced at 510 nm due to the formation of a complex between the ligand and aluminum ions at room temperature. As the concentration of Al3+ was increased, the fluorescence gradually increased. Other metal ions, such as K+, Ag+, Ca2+, Mg2+, Zn2+, Mn2+, Co2+, Ni2+, Cu2+, Cd2+, Cr3+, Fe3+, In3+, had no significant effect on the fluorescence. 相似文献
999.
Four new zinc(II) complexes Zn2(μ‐dmpz)2(Hdmpz)2(L1)2 ( 1 ) (Hdmpz = 3,5‐dimethylpyrazole, HL1 = 2‐methyl‐2‐phenoxypropanoic acid), Zn(Hdmpz)2(L2)2 ( 2 ) [HL2 = 2‐hydroxy‐5‐(phenyldiazenyl)benzoic acid], Zn2(μ‐dmpz)2(Hdmpz)2(L3)2 ( 3 ) [HL3 = 3,4‐(methylenedioxy)benzoic acid], and Zn2(μ‐dmpz)2(Hdmpz)2(L4)2 ( 4 ) [HL4 = 3‐(4‐methoxyphenyl)acrylic acid] were prepared and structurally characterized by different techniques including elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction analysis. The X‐ray studies suggested that all these complexes except compound 2 are centrosymmetric dinuclear complexes with a tetrahedral arrangement around each zinc ion, whereas compound 2 is a mononuclear complex. The pyrazole ligand is coordinated in both terminal as well as a bridging fashion in the dinuclear moiety, whereas the pyrazole ligand in compound 2 is coordinated only in monodentate terminal fashion with its neutral nitrogen group. In all four complexes the carboxylate functions behave as monodentate ligands. All complexes show intramolecular hydrogen bonding of N–H ··· O between N–H of pyrazole and nonbonded oxygen atom of carboxylate. Furthermore, rich intermolecular weak interactions such as classical hydrogen bonds, C–H ··· O, C–H ··· N, C–H ··· π, and CH3–π interactions exist and complexes 1 – 4 display a set of 3D superamolecular frameworks. In addition, the four compounds are thermally stable below 150 °C. 相似文献
1000.
Jin‐Peng Geng Prof. Dr. Zhao‐Xi Wang Qiong‐Fang Wu Ming‐Xing Li Prof. Dr. Hong‐Ping Xiao 《无机化学与普通化学杂志》2011,637(2):301-305
A new manganese(II) complex [Mn3(bidc)2(C2O4)(H2O)10]n ( 1 ) (bidc = benzimidazole‐5,6‐dicarboxylate) was synthesized and characterized by X‐ray crystallography. X‐ray diffraction shows that complex 1 has a neutral, one‐dimensional (1D) brick wall chain structure. With the intramolecular and intermolecular hydrogen bonding interactions, the adjacent chains are joined into a 3D suparmolecular architecture. IR spectroscopy and variable temperature magnetic susceptibility measurements were made, which indicated weak antiferromagnetic coupling between the MnII ions in complex 1 . 相似文献