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排序方式: 共有343条查询结果,搜索用时 31 毫秒
31.
Maria A. Peshkova Natalia V. Timofeeva Sergei M. Korneev Konstantin N. Mikhelson 《Electroanalysis》2010,22(19):2147-2156
A novel way of synthesis is developed for the Ba2+ selective neutral Ionophore 2a : 2,2′‐[1,2‐phenylenebis(oxyethane‐2,1‐diyloxy)]bis(N‐benzyl‐N‐phenylacetamide) and its methyl ( 2b ), buthyl ( 2c ), and hexyl ( 2d ) derivatives. Ba2+ selective electrodes based on Ionophores 2a – d are compared with those with commonly used Ionophore 1 : N,N,N′,N′‐tetracyclohexyl‐oxybis(o‐phenyleneoxy) diacetamide. It is shown that Ionophores 2a – d , particularly 2b , are superior for measurements of Ba2+ in the presence of Ca2+, and in acidic solutions. Segmented sandwich membrane studies suggest formation of complexes IL22+ for Ba2+, Ca2+ and Mg2+ ions with Ionophore 2b , while H+ ions apparently form complexes H2L2+. The values of the complex formation constants are consistent with the selectivity coefficients. 相似文献
32.
Russian Physics Journal - 相似文献
33.
Alexander S. Romanov Tatiana V. Timofeeva Mikhail Yu. Antipin 《Journal of organometallic chemistry》2011,696(23):3822-3825
Novel radial tetra(ferrocenyl)- and tetra(cymantrenyl)cyclobutadienecobalt complexes were prepared by metal carbonyls free protocol of [2 + 2] cycloaddition reaction of 1,2-diferrocenyl- or 1,2-dicymantrenylethynes with chlorotris(triphenylphospine)cobalt(I) and carboethoxycyclopentadienide sodium with good yields. The molecular structure of these products was confirmed with X-ray analysis, and their electrochemical behavior was studied. 相似文献
34.
Getmanenko YA Risko C Tongwa P Kim EG Li H Sandhu B Timofeeva T Brédas JL Marder SR 《The Journal of organic chemistry》2011,76(8):2660-2671
A series of trialkylsilyl-substituted 2,2'-dithiophene, 4,4'-di-n-hexyl-2,2'-dithiophene, 5,5'-dithiazole, and 2,2'-diselenophene with carbonyl (2a-d) and α-dicarbonyl bridges (3a-d) were prepared from readily available dihalides, using double lithiation followed by trapping with N,N-dimethylcarbamoyl chloride or diethyl oxalate (or N,N-dimethylpiperazine-2,3-dione), respectively. Cyclic voltammetry reveals that the first half-wave reduction potentials for this series of compounds span a wide range, from -1.87 to -0.97 V vs the ferrocene/ferrocenium couple at 0 V (0.1 M (n)Bu(4)NPF(6) in THF). A significant increase of the first half-wave reduction potential (by 0.50-0.67 V) was observed on substitution of the monocarbonyl bridge with α-dicarbonyl. Adiabatic electron affinity (AEA, gas phase) trends determined via density functional theory (DFT) calculations are in good agreement with the electrochemical reduction potentials. UV-vis absorption spectra across the series show a weak absorption band in the visible range, corresponding to the HOMO→LUMO transition within a one-electron picture, followed by a more intense, high-energy transition(s). Single-crystal X-ray structural analyses reveal molecular packing features that balance the interplay of the presence of the bulky substituents, intermolecular π-stacking interactions, and S···O intermolecular contacts, all of which affect the DFT-evaluated intermolecular electronic couplings and effective charge-carrier masses for the crystals of the tricyclic cores. 相似文献
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36.
The activities of 18 heteropoly acids (7 structural types) and two isopoly acids have been studied during L-sorbose acetonation. We have found acid H3PMo12O40 to be the most active. The purity of diacetone sorbose produced is proportional to its yield. 相似文献
37.
B. F. Kukharev V. K. Stankevich G. R. Klimenko T. F. Lelyukh V. A. Kukhareva S. S. Timofeeva 《Russian Journal of Applied Chemistry》2005,78(7):1197-1198
Polyvinyloxyalkylammonium chlorides were synthesized in up to 82% yields by alkylation of monoethanolamine polyvinyl ether with higher alkyl chlorides. The suitability of the resulting polyvinyloxyalkylammonium chlorides for treatment of lignin-containing wastewater by pressure flotation was tested. 相似文献
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S. A. Pavlova G. I. Timofeeva I. A. Ronova L. A. Pancratova 《Journal of Polymer Science.Polymer Physics》1980,18(1):1-18
The conformational parameters of three polyoxadiazoles were calculated by a direct computer simulation assuming free rotation about virtual bonds. The results obtained proved to be close to those derived from viscosity and sedimentation experiments. 相似文献