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31.
Synthesis and Isolation of the Titanium–Scandium Endohedral Fullerenes—Sc2TiC@Ih‐C80, Sc2TiC@D5h‐C80 and Sc2TiC2@Ih‐C80: Metal Size Tuning of the TiIV/TiIII Redox Potentials 下载免费PDF全文
Katrin Junghans Dr. Kamran B. Ghiassi Nataliya A. Samoylova Qingming Deng Marco Rosenkranz Prof. Marilyn M. Olmstead Prof. Alan L. Balch Dr. Alexey A. Popov 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(37):13098-13107
The formation of endohedral metallofullerenes (EMFs) in an electric arc is reported for the mixed‐metal Sc–Ti system utilizing methane as a reactive gas. Comparison of these results with those from the Sc/CH4 and Ti/CH4 systems as well as syntheses without methane revealed a strong mutual influence of all key components on the product distribution. Whereas a methane atmosphere alone suppresses the formation of empty cage fullerenes, the Ti/CH4 system forms mainly empty cage fullerenes. In contrast, the main fullerene products in the Sc/CH4 system are Sc4C2@C80 (the most abundant EMF from this synthesis), Sc3C2@C80, isomers of Sc2C2@C82, and the family Sc2C2 n (2 n=74, 76, 82, 86, 90, etc.), as well as Sc3CH@C80. The Sc–Ti/CH4 system produces the mixed‐metal Sc2TiC@C2 n (2 n=68, 78, 80) and Sc2TiC2@C2 n (2 n=80) clusterfullerene families. The molecular structures of the new, transition‐metal‐containing endohedral fullerenes, Sc2TiC@Ih‐C80, Sc2TiC@D5h‐C80, and Sc2TiC2@Ih‐C80, were characterized by NMR spectroscopy. The structure of Sc2TiC@Ih‐C80 was also determined by single‐crystal X‐ray diffraction, which demonstrated the presence of a short Ti=C double bond. Both Sc2TiC‐ and Sc2TiC2‐containing clusterfullerenes have Ti‐localized LUMOs. Encapsulation of the redox‐active Ti ion inside the fullerene cage enables analysis of the cluster–cage strain in the endohedral fullerenes through electrochemical measurements. 相似文献
32.
B. M. Bulychev R. A. Lunin V. A. Kul’bachinskii R. V. Shpanchenko V. I. Privalov 《Russian Chemical Bulletin》2004,53(8):1686-1692
One- or two-step reactions of potassium and rubidium fullerides with composition Mk C60 (M = K, Rb; k = 3—6) and K6C60 + m K mixtures (m = 1, 3) with anhydrous salts MCl3 (M = La, Pr, Nd, Sm, Gd, Tb, Yb, Lu, Y, Sc) and YbI2 in a toluene—THF medium afforded heterometallic fullerides M3–nMnC60 (n = 1—3). Among these compounds, substituted fullerides with composition M2MC60 (M = Yb, Lu, Sc) display superconducting properties with critical temperatures of 14—20 K.Published in Russian in Izvestiya Akademii Nauk.
Seriya Khimicheskaya, No. 8, pp. 1623–1628, August, 2004. 相似文献
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高纯氧化钪中稀土杂质的电感耦合等离子体质谱法测定 总被引:5,自引:0,他引:5
研究了用电感耦合等离子体质谱法测定高纯氧化钪中15个稀土杂质的方法。考察了基体效应及内标的作用,采用I或Cs为内标可很好补偿基体SC的影响。方法检测限为0.013-0.085ng/ml,加料回收率为91.2%-105.7%,相对标准偏 1.4%-8.1%。 相似文献
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Controllable synthesis and characterization of ammonium polyphosphate with crystalline form V by phosphoric acid process 总被引:2,自引:0,他引:2
Gousheng Liu Wenyan Chen Xinchun Liu Jianguo Yu 《Polymer Degradation and Stability》2010,95(9):1834-12155
Ammonium polyphosphate (APP) with crystalline form V (APP-V) was synthesized by heating a mixture of 85% food-grade phosphoric acid and melamine under dry ammonia atmosphere. Effects such as raw material ratios, charging methods, dehydration temperature, condensation temperature and condensation time were investigated. Its water solubility was tested, its XRD and FTIR were characterized and compared with those of industrial APP-I and APP-II. Results showed that the prepared APP-V was insoluble in water, its XRD spectrum was the same as APP-V in literature. The molecular structures of the prepared APP-V and APP-I/APP-II were speculated and discussed in detail. 相似文献
38.
Phase‐pure ammonium catena‐polyphosphate IV [NH4PO3]x was synthesized by heating NH4H2PO4 in a tube furnace under an ammonia gas flow. The product contained single crystals of [NH4PO3]x IV appropriate for an X‐ray structure determination enabling structure refinement of this compound. The pseudo‐merohedrally twinned crystals of [NH4PO3]x crystallize in the monoclinic crystal system (P21/c, no. 14, a = 2270.3(5), b = 458.14(9), c = 1445.1(3) pm, β = 108.56(3)°, Z = 4, 2264 data, R1 = 0.076). In the unit cell the catena‐polyphosphate chain anions run parallel [010] with a chain‐periodicity P = 2 and a stretching factor fs = 0.94. The chain anions are interconnected through extensive hydrogen bonding towards the ammonium ions. Due to ‘chemical twinning’ a novel catena‐polyphosphate structure type is realized in [NH4PO3]x IV. The vibrational spectra of [NH4PO3]x IV are reported as well. 相似文献
39.
Zhanghua Zeng Dr. Angel A. J. Torriero Dr. Alan M. Bond Prof. Leone Spiccia Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(30):9154-9163
The [Fc? bis{ZnII(TACN)(Py)}] complex, comprising two ZnII(TACN) ligands (Fc=ferrocene; Py=pyrene; TACN=1,4,7‐triazacyclononane) bearing fluorescent pyrene chromophores linked by an electrochemically active ferrocene molecule has been synthesised in high yield through a multistep procedure. In the absence of the polyphosphate guest molecules, very weak excimer emission was observed, indicating that the two pyrene‐bearing ZnII(TACN) units are arranged in a trans‐like configuration with respect to the ferrocene bridging unit. Binding of a variety of polyphosphate anionic guests (PPi and nucleotides di‐ and triphosphate) promotes the interaction between pyrene units and results in an enhancement in excimer emission. Investigations of phosphate binding by 31P NMR spectroscopy, fluorescence and electrochemical techniques confirmed a 1:1 stoichiometry for the binding of PPi and nucleotide polyphosphate anions to the bis(ZnII(TACN)) moiety of [Fc? bis{ZnII(TACN)(Py)}] and indicated that binding induces a trans to cis configuration rearrangement of the bis(ZnII(TACN)) complexes that is responsible for the enhancement of the pyrene excimer emission. Pyrophosphate was concluded to have the strongest affinity to [Fc? bis{ZnII(TACN)(Py)}] among the anions tested based on a six‐fold fluorescence enhancement and 0.1 V negative shift in the potential of the ferrocene/ferrocenium couple. The binding constant for a variety of polyphosphate anions was determined from the change in the intensity of pyrene excimer emission with polyphosphate concentration, measured at 475 nm in CH3CN/Tris‐HCl (1:9) buffer solution (10.0 mM , pH 7.4). These measurements confirmed that pyrophosphate binds more strongly (Kb=(4.45±0.41)×106 M ?1) than the other nucleotide di‐ and triphosphates (Kb=1–50×105 M ?1) tested. 相似文献
40.
Jianyun Wang Dongming Zhang Xixun Yu Changsheng Zhao 《Polymer Degradation and Stability》2010,95(7):1205-1012
Organic and inorganic composite material is becoming a solution on making the mechanical and degradation properties of biomaterial more suited. Porous calcium polyphosphate was immersed into different concentrations of carboxymethyl chitosan before immersing 10% alginate dialdegyde. After freeze-drying, the scaffolds were performed in physiologic saline. At stated day, the weightloss, Ca2+ concentration, pH value and morphology were measured. The biocompatibility of the composite was demonstrated by extract and direct contact tests. As the results showed, the degradation rates of composites were faster, and the compressive strength became bigger because of the cross-linked network formed by Carboxymethyl chitosan (CMC) and alginate dialdehyde (ADA). The pH value of composite was higher than that of calcium polyphosphate (CPP) due to the organic part of composite’s pH was in slight alkaline. From the SEM, the cross-linked network structure could be observed clearly. Because the glycosaminoglycans-like chains in CMC molecules, which are typically presented in extracellular matrix (ECM), extractions of composite material gave the cells good adhesion and growth condition. All the results testified the composite scaffold was a good candidate for bone repair. 相似文献