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131.
特征线法在求解非线性液相吸附色谱模型中的应用 总被引:1,自引:0,他引:1
本文应用特征线法求解非线性液相吸附色谱分离过程模型,论述了特征线法的原理和步骤,讨论了时间步长和空间步长对模型数值解的影响,并用色谱分离甘露醇和山梨醇以及分离蔗糖和还原糖的实验进行验证,用特征线法计算的理论流出曲线与实验流出线吻合较好。本文还分折了模型中各个参数的灵敏度,结果表明:吸附等温方程Q=Ci*/(ai+biCi*)中参数ai比参数bi以及总传质系数ki有更高的灵敏度。 相似文献
132.
Zhong Lin Wang 《Microscopy and microanalysis》2004,10(1):158-166
Characterizing the physical properties of individual nanostructures is challenging because of the difficulty in manipulating the objects of sizes from nanometers to micrometers. Most nanomeasurements have been carried using scanning probe microscopy. In this article, we demonstrate that transmission electron microscopy can be a powerful tool for quantitative measurements of the mechanical and electrical properties of a single nanostructure. Dual-mode resonance of an oxide nanobelt has been observed, and its bending modulus has been measured. An in situ technique was demonstrated for measuring the work function at the tip of a carbon nanotube. The ballistic quantum conductance of a multiwalled carbon nanotube was observed at room temperature using the setup in TEM. It is concluded that in situ measurement by directly linking structure with property is a future direction of electron microscopy. 相似文献
133.
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
134.
A procedure has been developed to coat micron-sized poly(styrene-co-3-trimethoxysilyl propyl methacrylate) microspheres with
a smooth layer of polysiloxane by the hydrolysis and condensation of methyl trimethoxylsilane (MTMS). Firstly, polystyrene
microspheres containing silanol groups were prepared by conventional dispersion polymerization using 3-(trimethoxysilyl) propyl
methacrylate (MPS) as a functional comonomer in an ethanol/water medium. Secondly, the synthesis of the polysiloxane shell
was carried out using a sol–gel process of MTMS. The thickness of the shells can be easily varied with different copolymer
seeds and MTMS feed ratio. When we used copolymer particles with 2.00 μm diameter as seeds, the thickness of the polysiloxane
shells can be varied from 0.10 to 0.18 μm. The core/shell structure of the composite microspheres was characterized by transmission
electron microscope (TEM). 相似文献
135.
用计算机多元分析研究冠心病微量元素谱,识别冠心病患者与健康者;非线性映射法判别率男性86.6%,女性96.2%;SIMCA差别法正确回判率男性85.0%,女性88.3%。 相似文献
136.
137.
Zhong Jie ZOU Yue Sheng DONG Jun Shan YANG 《中国化学快报》2005,16(11):1484-1486
A new β-carboline alkaloid, 4-(9H-β-carbolin-1-yl)-4-oxobutyric acid and a new derivate of isoferulic acid, (E)-3-(3-hydroxy-4-methoxyphenyl)acrylic acid carboxymethyl ester, were isolated from the roots of Anemone altaica. Their structures were determined on the basis of spectral data. 相似文献
138.
烷基极化效应与X=O键伸缩振动频率 总被引:2,自引:0,他引:2
烷基取代物R’X=0的X=0键伸缩振动频率ν与烷基R的极化效应指数PEI(R)的关系可表示为:ν=a bPEI(R)。研究结果表明,烷基的极化效应使X=0键的伸缩振动频率降低。 相似文献
139.
水煤气变换反应的微观动力学分析──Cu基催化剂上H_2S中毒失活原因的 Monte Carlo 模拟研究 总被引:1,自引:0,他引:1
用BOCMP方法及MonteCarlo模拟技术,对H2S导致Cu基催化剂失活的原因进行了计算分析。研究结果表明,当原料气中存在H2S时,WGS反应的活化能明显高于无H2S时的活化能,随着表面H2S浓度的增大(θ=0,0.10,0.25),反应的活化能也逐渐变大(其大小比为1∶1.34∶3.3),究其原因可归结为H2S的存在使得反应物分子的吸附热减小,从而使H2O的解离吸附(WGS反应的速控步骤)活化能增大。 相似文献
140.
本文通过红外光谱(FT-IR)测量数据和预测数据,计算与研究了十九种长链正烷基脂肪酸(简称脂肪酸或碳酸)的碳链骨架振动能量。结果显示出脂肪酸的碳链骨架振动能量随碳数增加呈阶梯状关系,而且脂肪酸的碳链骨架振动能量∑E出现奇偶数更迭规律。此结果可用来解释脂肪酸的熔点或熔化热呈现奇偶数更迭现象。 相似文献