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排序方式: 共有1212条查询结果,搜索用时 609 毫秒
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Ozao R. Yoshida H. Inada T. Ochiai M. 《Journal of Thermal Analysis and Calorimetry》2003,72(1):113-118
Nanoporous alumina membrane prepared by anodic oxidation using sulfuric acid electrolyte was subjected to TG-DTA and X-ray
Photoelectron Spectroscopy (XPS or ESCA) to further study the distribution of sulfur. In XPS study, Ar+ ion bombardment was performed on the sample to etch the surface at a rate of 3 nm min-1. As a result, sulfur was found to be concentrated within a depth of 3nm from the surface. The S content of the surface was
found to be 2.7±0.5 wt%, and that at a depth of ca. 3 nm and ca. 10 nm was found to be as low as about 0.6±0.11 wt% (5.37±1.0
wt%→ 1.26±0.2wt% SO2). In TG-DTA, the mass loss of 7.3% was in fair agreement with that calculated on XPS results (7.1±1.2%).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
Chunlin Li Yilu Fu Guozhu Bian Tiandou Hu Yaning Xie Jing ZhanDepartment of Chemical Physics University of Science and Technology of China Hefei China Institute of High Energy Physics Chinese Academy of Sciences Beijing China 《天然气化学杂志》2003,12(3)
The Ni/CeO2-ZrO2-Al2O3 catalyst with different Al2O3 and NiO contents were prepared by hydrothermal synthesis method. The catalytic performance for CO2 reforming of CH4 reaction, the interaction among components and the relation between Ni content and catalyst surface basicity were investigated. Results show that the interaction between NiO and Al2O3 is stronger than that between NiO and CeO2-ZrO2.The addition of Al2O3 can prevent the formation of large metallic Ni ensembles, increase the dispersion of Ni, and improve catalytic activity, but excess Al2O3 causes the catalyst to deactivate easily. The interaction between NiO and CeO2 results in more facile reduction of surface CeO2. The existence of a small amount of metallic Ni can increase the number of basic sites. As metallic Ni may preferentially reside on the strong basic sites, increasing Ni content can weaken the catalyst basicity. 相似文献
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采用聚乙烯醇对碳纳米管表面进行改性,通过化学沉淀法将Al(OH)3均匀沉积在碳纳米管表面,然后在氮气气氛下于500 ℃煅烧2 h,制备出氧化铝/碳纳米管复合材料。采用TEM、TG、DTA、XRD、IR、氮吸附脱附(比表面积及孔结构分析)等对氧化铝/碳纳米管复合材料进行表征,结果表明:未经聚乙烯醇改性的碳纳米管,氧化铝与碳纳米管相互分离;经聚乙烯醇改性的碳纳米管,氧化铝与碳纳米管结合良好。经聚乙烯醇改性的碳纳米管表面均匀覆盖一层聚乙烯醇膜,通过聚乙烯醇的吸附作用, Al(OH)3沉积在碳纳米管表面形成一层连续的覆盖层。 相似文献
6.
氧化铝具有许多重要的工业用途,而制备高热稳定活性氧化铝的技术也在不断地发展[1,2],因此,研究其高温烧结下的相变过程很有意义.离子深法作为新型测试手段,已成功地用于生物大分子结构与功能研究方面[‘],而在固体材料测试中的应用尚未见报道.我们以EU’“作为荧光探针,并结合**D和*nR研究了川对。在不同烧结温度下的相变过程.1实验部分样品的制备采用复盐分解法.先将Elf刀s用高纯硝酸溶解定容.以占AlzO。重量1%的量加入到硫酸铝锭溶液中,进行超声处理,冷冻干燥.再依次登于900”C、1000C、1100C、1200C的高温炉… 相似文献
7.
La2O3对氧化铝透明陶瓷显微结构和透光性能的影响 总被引:4,自引:1,他引:4
采用传统无压烧结工艺在氢气氛下制备Al2O3透明陶瓷。实验结果表明:MgO和La2O3复合添加时,随着La2O3掺杂量的增加体积密度总体上保持上升的趋势。随着保温时间的延长,陶瓷的致密化程度增大,残余气孔逐步排出,晶粒进一步长大。采用La2O3和MgO复合添加比单独掺入MgO陶瓷样品透过率更高,掺杂效果更好。在烧结温度为1750℃,保温时问为1h条件下,在波艮为300~800nm测试范围内,陶瓷样品的全透过率大于82%,最大值为86%。 相似文献
8.
A. V. Fionov M. V. Burova E. A. Tveritinova I. V. Krylova 《Russian Chemical Bulletin》2006,55(4):639-644
Donor-acceptor properties of alumina modified with lithium cations were studied by ESR of paramagnetic complexes of adsorbed
anthraquinone. The results were compared with the data on negative ion emission (exoemission) accompanying the decomposition
of isopropyl alcohol in the adsorption layer. The data on the activity measured by the pulse microcatalytic technique in isopropyl
alcohol decomposition are discussed. Small additives of lithium were found to promote catalytic activity of the samples. The
role of acid and basic sites in isopropyl alcohol decomposition was discussed.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 616–621, April, 2006. 相似文献
9.
A.G. Dobrikova M.I. Dimitrov S.G. Taneva I.B. Petkanchin 《Colloids and surfaces. B, Biointerfaces》2007,56(1-2):114-Optics
Using microelectrophoresis and electric light scattering techniques, we investigated the adsorption characteristics, surface coverage and surface electric parameters of superstructures from two isoforms of plastocyanin, PCa and PCb, in an oxidized state adsorbed on β-ferric hydrous oxide particles. The surface electric charge and electric dipole moments of the composite particles and the thickness of the protein adsorption layer are determined in a wide pH range, at different ionic strengths and concentration ratios of PC to β-FeOOH. The adsorption of the two proteins was found to shift the particles’ isoelectric point and to alter the total electric charge and the electric dipole moments of the oxide particles to different extent. A “reversal” in the direction of the permanent dipole moment is observed at lower pH for PCb- than for PCa-coated oxide particles. Strict correlation is found between the changes in the electrokinetic charge of the composite particles and the variation in their “permanent” dipole moments. Data suggest that the adsorption of the proteins is driven by electrostatic and/or hydrophobic interactions with the oxide surfaces dependent on pH. The adsorption behaviour is consistent with the involvement of the “eastern” and “northern” patches of the plastocyanin molecules in their adsorption on the oxide surfaces that are differently charged depending on pH. 相似文献
10.
V. B. Vol'eva A. I. Prokofev A. Yu. Karmilov N. L. Komissarova I. S. Belostotskaya T. I. Prokofeva V. V. Ershov 《Russian Chemical Bulletin》1998,47(10):1920-1923
The formation of semiquinone and phenoxazyl radicals and metallocomplexes with semiquinone ligands was observed by ESR during
the interaction of di-tert-butylpyrocatechol with Al2O3, ZnO, SiO2, and TiO2. In the case of different modifications of SiO2, admixtures of TiO2 exhibit a higher reactivity in complex formation with the organic substrate.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1975–1978, October, 1998. 相似文献