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101.
Ilona Šperlingová Ludmila Dabrowská Vladimír Stránský Jan Kučera Miloň Tichý 《Accreditation and quality assurance》2006,11(5):231-235
The candidate reference material (RM) was prepared by freeze-drying pooled urine samples obtained from healthy persons occupationally exposed to toluene. Homogeneity testing yielded no significant differences of urinary concentrations of o-cresol and phenol in 15 randomly selected units of RM. Stability testing showed no significant changes of concentrations of the above analytes over a period of 6 months. Property (pre-certified) values of phenol and o-cresol concentrations and their uncertainties (9.06±0.47 mg l−1 and 1.03±0.06 mg l−1, respectively) were estimated from results of a small-scale interlaboratory comparison in which two laboratories participated using four different analytical methods. 相似文献
102.
Vladimir I. Bregadze Ludmila M. Golubinskaya Boris I. Kozyrkin 《Journal of Cluster Science》2002,13(4):631-636
Three new methods for large scale synthesis of electronic grade trimethylgallium and trimethylindium are presented. These methods are based on direct synthesis of trialkylgallium compounds from the Ga/Mg alloy or the mixture of this metals and alkyl halides, RX. The first method consists in the cleavage of the stable trimethylgallium-diethyl ether adduct by heating it in the mixture with ether of higher boiling point. The second one is the reaction of the mixture of Ga and Mg with methyl iodide in a high boiling ether solvent such as diisoamyl ether, i-Am2O. The third method consist in preliminary formation of the stable adducts of trimethylgallium or trimethylindium and alkali metal fluorides from their etherates, followed by removing ethers and thermal decomposition of adducts to yield free trimethylgallium or trimethylindium respectively. 相似文献
103.
Ludmila úrková Renáta Kucsera Róbert Gyepes Michal Sivák 《Monatshefte für Chemie / Chemical Monthly》2003,134(8):1071-1079
Summary. Two novel compounds, [Co(phen)3]2V4O12·phen·22H2O (1) and [Ni(phen)3]2 V4O12·phen·22H2O (2), were prepared from KVO3–1,10-phenanthroline (phen)–Co(NO3)2, resp. NiCl2–H2O reaction systems. The compounds 1 and 2 are isomorphous and crystallize in triclinic system, space group P-1. Their crystal structures are formed by two types of layers parallel to 001: a cationic one consisting of [MII(phen)3]2+ ions and an anionic one containing the cyclic V4O12
4– anions. The solvate phenanthroline and crystal water molecules are located in the cationic and anionic layers, respectively. The IR spectra of 1 and 2 are consistent with the presence of the cyclic V4O12
4– anions in the complexes.Received November 13, 2002; accepted (revised) February 3, 2003
Published online June 2, 2003 相似文献
104.
Galina A. Bukhtiyarova Irina V. Delii Nailya S. Sakaeva Vasiliy V. Kaichev Ludmila M. Plyasova Valerii I. Bukhtiyarov 《Reaction Kinetics and Catalysis Letters》2007,92(1):89-97
The effect of the calcination temperature on the properties of supported iron oxide catalysts for hydrogen sulfide oxidation
prepared by impregnation of silica with iron(III) nitrate has been studied. An increase in the calcination temperature was
found to diminish the catalytic activity of the Fe2O3/SiO2 catalysts in hydrogen sulfide oxidation. This behavior can be explained by the agglomeration of iron oxide particles and
by a decrease in the surface concentration of active sites. It has been shown that an increase in the calcination temperature
makes the catalyst more stable towards the sulfidation of the active component (Fe2O3) to the iron disulfide phase. 相似文献
105.
Acid hydrolysis of [Ru(5)(CO)(15)(mu(4)-PN(i)Pr(2))] (2) or protonation of the anionic PO cluster [Ru(5)(CO)(15)(mu(4)-PO)](-) (3) affords the hydroxyphosphinidene complex [Ru(5)(CO)(15)(mu(4)-POH)].1.[H(2)N(i)()Pr(2)][CF(3)SO(3)], which cocrystallizes with a hydrogen-bonded ammonium triflate salt. Reaction of [Ru(5)(CO)(15)(mu(4)-PN(i)Pr(2))] (2) with bis(diphenylphosphino)methane (dppm) leads to [Ru(5)(CO)(13)(mu-dppm)(mu(4)-PN(i)Pr(2))] (4). Acid hydrolysis of 4 leads to the dppm-substituted hydroxyphosphinidene [Ru(5)(CO)(13)(mu-dppm)(mu(4)-POH)] (5), which is analogous to 1, but unlike 1, can be readily isolated as the free hydroxyphosphinidene acid. Compound 5 can also be formed by reaction of 3 with dppm and acid. The cationic hydride cluster [Ru(5)(CO)(13)(mu-dppm)(mu(3)-H)(mu(4)-POH)][CF(3)SO(3)] (6) can be isolated from the same reaction if chromatography is not used. Compound 4 also reacts with HBF(4) to form the fluorophosphinidene cluster [Ru(5)(CO)(13)(mu-dppm)(mu(4)-PF)] (7), while reaction with HCl leads to the mu-chloro, mu(5)-phosphide cluster [Ru(5)(CO)(13)(mu-dppm)(mu-Cl)(mu(5)-P)] (8). 相似文献
106.
The kinetics and mechanism of transformation reaction of S-[1-(4- methoxyphenyl)pyrrolidin-2-one-3-yl]-N-methyl-isothiuronium bromide into 2-methylimino-5-[2-(4-methoxyphenylamino) ethyl)]thiazolidin-4-one have been studied in aqueous solutions of amine buffers (pH 8.1-11.5) and sodium hydroxide solutions (0.005-0.5 mol l-1) at 25 degrees C and at I = 1 mol l-1 at pseudo-first-order reaction conditions. The kinetics observed shows that the transformation reaction is subject to general base, general acid, and hydroxide-ion catalyses. The rate-limiting step of transformation is the splitting-off a proton from the tetrahedral intermediate In. The value of pKa for S-[1-(4-methoxyphenyl)- pyrrolidin-2-one-3-yl]-N-methylisothiuronium bromide has been determined from the kinetic data (pKa = 8.75 +/- 0.10) and by potentiometric titration (pKa = 8.90 +/- 0.05). With increasing pKa value of the acid buffer component, the value of Br?nsted coefficient beta gradually decreases from about 0.7 to almost zero. The value of pKa approximately 10 for the intermediate to base-catalysed transformation has been found from this dependence. In the N-methylpyrrolidine and triethylamine buffers, the rate-limiting step of transformation is changed into ring opening of In-, and the general-base-catalysed reaction changes into a specific-base-catalysed one. 相似文献
107.
D. F. Calhane C. M. Alber J. Ludmila B. G. Šimek V. Kohlschütter H. Schödl P. Jacquet M. Giordani H. Kiyota J. Guzmán A. Ranmcaño C. G. Donova B. Jones M. G. Raeder R. Höiors L. Lucchi A. Bartocci W. Moldenhauer N. Isgarischew A. F. Prede G. Illari G. Damany J. Heyrovský D. Ilkovič G. Semerano I. Slendyk G. Devoto A. Ratti H. Mandai S. Zeltzer G. Kimura M. Tokuoka I. Smolér R. Brdička A. Scheicher 《Analytical and bioanalytical chemistry》1934,96(5-6):193-209
108.
Alaverdian L Alaverdian S Bilenko O Bogdanov I Filippova E Gavrilov D Gorbovitski B Gouzman M Gudkov G Domratchev S Kosobokova O Lifshitz N Luryi S Ruskovoloshin V Stepoukhovitch A Tcherevishnick M Tyshko G Gorfinkel V 《Electrophoresis》2002,23(16):2804-2817
We have developed a family of high-performance capillary DNA sequencing instruments based on a novel multicolor fluorescent detection technology. This technology is based on two technical innovations: the multilaser excitation of fluorescence of labeled DNA fragments and the "color-blind" single-photon detection of modulated fluorescence. Our machines employ modern digital and broadband techniques that are essential for achieving superior instrument performance. We discuss the design and testing results for several versions of the automated single lane DNA sequencers, as well as our approach to scaling up to multilane instruments. 相似文献
109.
Ilona Šperlingová Ludmila Dabrowská Miloň Tichý J. Kučera 《Analytical and bioanalytical chemistry》1998,361(8):756-760
Two batches of a reference material (RM) “total protein in human urine” were prepared for quality assurance in the determination of human urinary proteins. The material was prepared by freeze-drying of a pooled urine sample obtained from healthy volunteers. Protein concentrations in both batches were within physiological values, close to their upper limit. Interlaboratory comparisons conducted in 26 laboratories using the standard operation procedures elaborated for six of the most frequently employed methods (biuret, Bradford, Exton, Lowry, Pesce, and Watanabe) revealed that the results obtained by the individual methods were significantly different due to various reaction mechanisms involved. It was therefore necessary to certify the mean values and their uncertainties individually for each method. These operationally defined certified or information values are valid only when the prescribed standard operation procedures are strictly followed. 相似文献
110.