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排序方式: 共有116条查询结果,搜索用时 15 毫秒
1.
Leonid B. Krivdin Gennady A. Kalabin Raisa N. Nesterenko Boris A. Trofimov 《Tetrahedron letters》1984,25(42):4817-4820
A positive contribution of more than 7 Hz to the direct 13C-13C spin-spin coupling constants induced by the proximity of the nitrogen lone pair in syn-orientation to the coupled nuclei allows an unambiguous configuration assignment of diverse oximes. 相似文献
2.
R. F. Klevtsova L. A. Glinskaya A. K. Il'yasova G. L. Esnazarova R. I. Maksimovskaya 《Journal of Structural Chemistry》1990,31(6):933-939
Institute of Inorganic Chemistry, Academy of Sciences of the USSR, Siberian Branch. Institute of Chemical Sciences, Academy of Sciences of the Kazakh SSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 31, No. 6, pp. 97–103, November–December, 1990. 相似文献
3.
Comparative study of photodynamic properties of 13,15-N-cycloimide derivatives of chlorin p6 总被引:1,自引:0,他引:1
Feofanov A Sharonov G Grichine A Karmakova T Pljutinskaya A Lebedeva V Ruziyev R Yakubovskaya R Mironov A Refregier M Maurizot JC Vigny P 《Photochemistry and photobiology》2004,79(2):172-188
Comparative study of 13,15-[N-(2-hydroxyethyl)]cycloimide chlorin p6 (2), 13,15-(N-acetoxy)cycloimide chlorin p6 (3), 13,15-(N-hydroxy)cycloimide chlorin p6 methyl ester (4) and 13,15-(N-methoxy)cycloimide chlorin p6 methyl ester (5) together with the previously investigated 13,15-[N-(3-hydroxypropyl)]cycloimide chlorin p6 (1) was performed. The dependence of the key photodynamic properties of 1-5 on the introduced substituents was analyzed. The photoinduced cell-killing activity of 4 is 100- and 280-fold higher than that of chlorin p6 and Photogem, respectively, as estimated on A549 human lung adenocarcinoma cells. The activity is reduced eight times in the order 4 > 5 > 1 > 2 > 3. The intracellular accumulation of 1-5 occurs in cytoplasm in a monomeric form bound to the lipids of cellular membranes. This form of 1, 2, 3, 4 and 5 is characterized by the high quantum yield of singlet oxygen generation, which depends on the introduced substituents, 0.66, 0.59, 0.35, 0.51 and 0.73, respectively. The photostability is two-fold less for 1 and four-fold less for 2, 3 and 5 than for 4. The rates of cellular uptake and efflux of 1-5 vary widely, thus providing the way to optimize the pharmacological properties of the photosensitizer (PS) using the respective substituents. Modifying the substituents, 1-5 were targeted to different cellular organelles. The enhanced accumulation in the Golgi apparatus and mitochondria complemented with diffuse staining of intracellular membranous structures is a property of 1-4. Compound 5 accumulates selectively in the lipid droplets and stains weakly perinuclear structures. Temperature-sensitive mechanisms of transport are responsible for the 1-4 uptake. Diffusion can play a role in the internalization of 5 but not of 1-4. Endocytosis via caveolae, clathrin-dependent and adenosine triphosphate-dependent pathways are not noticeably involved in the 1-5 internalization. Independently from their intracellular localization 1, 4 and 5 are highly efficient near-IR PS, which induce predominantly an apoptotic type of cell death under conditions providing ca 50% level of phototoxicity and necrosis at the 100% level of phototoxicity. 相似文献
4.
R. I. Maksimovskaya N. N. Chumachenko D. V. Tarasova 《Reaction Kinetics and Catalysis Letters》1985,28(1):111-116
Thermal decomposition of 10-molybdo-2-vanadosilicic heteropolyacid has been studied by29Si and51V-NMR method.29Si-NMR MAS spectra of solid samples indicate that the HPA begins to decompose at T<300°C and the decomposition is complete at 300–400°C.
29Si 51V Si–Mo-V () 12- . 29Si MAS , 300°C 300–400°C.相似文献
5.
O. A. Kholdeeva R. I. Maksimovskaya G. M. Maksimov K. I. Zamaraev 《Reaction Kinetics and Catalysis Letters》1998,63(1):95-102
Alkylammonium salts of Ti(IV)-substituted heteropolytungstate, PW11TiO
10
5−
, catalyze the oxidation of methyl phenyl sulfide with hydrogen peroxide. The yield of the corresponding sulfoxide and sulfone
is practically quantitative. A31P NMR study confirms the formation and reactivity of the PW11O39TiO
2
5−
peroxo complex in organic media. 相似文献
6.
Yu. V. Chernyshova L. I. Kuznetsova R. I. Maksimovskaya K. I. Matveev 《Reaction Kinetics and Catalysis Letters》1989,38(1):57-62
The rate constants of interactions of PW12-nVnO40
(3+n)– (n=1–4) heteropoly anions (HPAs) and various PW10V2O40
–5 isomers with VO2+ were measured. The reactions occurred via formation of intermediate active complexes with V(IV) ions incorporated into the coordination sphere of HPA.
VO2+ PW12-nVnO40 –(3+n) (n=1–4) PW10V2O40 –5. , V(IV) .相似文献
7.
8.
Tatiana Semashko Raisa Mikhailova Almira Ramanaviciene Arunas Ramanavicius 《Applied biochemistry and biotechnology》2013,171(7):1739-1749
Glucose oxidase (GOx) from Penicillium funiculosum 46.1 was purified using step-by-step ultrafiltration and it was characterized by spectrophotometric and spectrofluorometric methods. It was shown that spectra of GOx produced by P. funiculosum are typical for flavoproteins. Absorption spectrum has distinct peaks at 380 and 457 nm, excitation spectrum at 373 and 447 nm, and emission spectrum at 530 and 562 nm. The pH correlation of enzyme activity and catalytic characteristics in various buffer systems (phosphate (pH 5.0–9.0), citrate (pH 3.0–5.0), citrate-phosphate (pH 3.0–9.0), and universal (pH 3.0–9.0)) were registered. It was determined that the GOx is the most efficiently interacting with substrate (glucose) in phosphate buffer at pH 7.0 with k cat/K m?=?21,825 M?1 s?1. Interaction of several different redox mediators (9,10-phenantroline-5,6-dione, 9,10-phenanthrenequinone, N-methylphenazonium methyl sulfate, ferrocene, ferrocenecarboxylic acid, α-methylferrocenemethanol, ferrocenecarboxaldehyde) with GOx from P. funiculosum was investigated by evaluation of the difference in fluorescence emission intensity of FAD(oxidized) and FADH2(reduced) forms. It was found that 9,10-phenantroline-5,6-dione and 9,10-phenanthrenequinone are the best redox mediators for this type of GOx. Figure
? 相似文献
9.
Aqueous molybdate solutions with molybdenum concentrations of [Mo]=1, 0.4, and 0.2 M have been studied by NMR at pH 7-1 and in 0.3-6 M HClO4. The 95Mo NMR spectrum of isopolyanion (IPA) Mo7O24(6-) (I) at pH=5 consists of a signal at 210 ppm and two overlapping peaks at 32 and approximately 15 ppm with the intensity ratio approximately 1:4:2, and that of beta-Mo8O26(4-) (II) consists of two signals at approximately 100 and 10 ppm with the intensity ratio approximately 1:3. A broad 95Mo NMR line at around 0 ppm was observed in the pH range of IPA Mo36O112(8-) (III), and a signal of cationic oxospecies including MoO2(2+) (IV) was observed from -62 to -69 ppm. Two protonation sites of IPA I have been identified from 17O NMR spectra, which suggests binding of up to two protons. The distribution diagram, derived from the 95Mo NMR spectra, is given for [Mo]=0.4 M. The 95Mo NMR signals shift to lower frequencies with increasing number and strength of the Mo-O terminal bonds. 相似文献
10.