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31.
High-quality online course materials were reconstructed through feedback from undergraduate students and online data analysis regarding constructed learning materials on the Chao Xing Learning Platform. They were used for studying organic chemistry courses online and offline in university for nationalities. This model, based on student-centered teaching, can effectively transform students from passively accepting knowledge to actively learning and internalizing knowledge. This strategy can also enhance the students' learning initiative and the effects of learning, and hopefully be helpful to the universities in multi-ethnic areas in developing fundamental disciplined construction of organic chemistry and other courses. 相似文献
32.
Sakae Uemura Haruo Miyoshi Masaya Okano Isao Morishima Toshiro Inubushi 《Journal of organometallic chemistry》1979,165(1):9-19
Treatment of norbornene, norbornadiene, benzonorbornadiene, and chloro- and methoxy-benzonorbornadiene with thallium(III) acetate in methanol affords only the corresponding cis-exo-acetoxythallation adducts in a sharp contrast to oxymercuration of such strained olefins where methoxymercuration prevails. In the cases of substituted benzonorbornadienes the products are obtained as the regioisomeric mixtures, the isomer ratio being determined by 13C NMR. In the cases of 5-norbornene-2,3-dicarboxylic anhydride, 5-norbornene-2-methyl-2,3-dicarboxylic anhydride, and 5-norbornen-2-endo-carboxylic acid, lactonization occurs to give a trans-oxythallation adduct having a lactone ring, no introduction of either methoxy or acetoxy groups being observed. 1H and/or 13C NMR data for several new oxythallation adducts are provided. The alkaline sodium borohydride reduction of adducts in methanol affords mainly the parent olefin together with 10–16% yields of the corresponding exo-alcohol. 相似文献
33.
Sz. Vass 《Chemical physics letters》1980,70(1):135-137
The small number of reagents solubilized in a micelle prohibits the use of conventional reaction kinetics. In order to describe the kinetics of the reaction A + B ? AB proceeding in a micellar phase, a stochastic model is evaluated. The deviation of these results from those obtained by conventional kinetics may be as high as 20%. 相似文献
34.
Zn3V3O8 two-dimensional micro sheets are successfully synthesized by combination of solvothermal method and heat treatment. The Zn3V3O8 has better electrochemical performances after calcinations. 相似文献
35.
Vikram S. Kushawaha 《Chemical physics letters》1980,72(3):451-454
A laser-induced chemical reaction of I2 + C2H2 has been studied and the formation of cis and tians isomers of 1,2-diiodoethylene has been observed. The ratio of the two isomers of 1,2-diodoethylene changes markedly upon changing the laser wavelengths of excitation of the I2 molecule 相似文献
36.
Aromatic hydrocarbons provide nucleation centers for the formation of clusters of inert gases in high-flow supersonic beams. Large clusters of Ar, each containing a single tetracene (T) molecule, were prepared by supersonic expansion of the seeded gas at pressures p = 3000–13000 Torr and interrogated by laser-induced fluorescence spectroscopy Evidence is reported for homogeneous line broadening of large TArn clusters prepared at p? 8000 Torr. 相似文献
37.
Lorraine P. McDonnell Bushnell Eric R. Evitt Robert G. Bergman 《Journal of organometallic chemistry》1978,157(4):445-456
Reactions of η5-cyclopentadienylbis(triphenylphosphine)cobalt(I) (5) with several 2,n-alkadiynes (2) were investigated. Each of these reactions leads initially to a material in which one of the acetylene functional groups is π-coordinated to cobalt; this complex then undergoes conversion to a metallocycle. In cases where the two acetylene functions are connected by three- and four-carbon bridges (2b, 2c), metallocycles formed by intramolecular reaction of two acetylene functions in the same molecule may be isolated. In cases where the acetylene functions are joined by larger or smaller bridges, the reactions are more complex, and both inter- and intramolecular metallocycles are formed. Reactions of 5 with 1,8-bis(trimethylsilyl)-1,7-octadiyne (16) gives an isolable crystalline mono-acetylene complex (17), this material is stable in the solid state but undergoes conversion to metallocycle (18) in benzene solution. The relationship of these results to the mechanism of the CpCo(CO)2-catalyzed benzocycloalkene synthesis is discussed; it is suggested that intramolecular metallocycles are intermediates in reactions leading to benzocyclopentanes and -cyclohexenes, but intermolecular metallocycles are probably involved in reactions leading to benzocyclobutenes. 相似文献
38.
Ailing Zhu Yingying Guo Guangliang Liu Maoyong Song Yong Liang Yong Cai Yongguang Yin 《中国化学快报》2019,30(12):2241-2244
Dark formation of hydroxyl radical upon oxidation of reduced iron minerals plays an important role in the degradation and transformation of organic and inorganic pollutants. Herein, we compared the hydroxyl radical formation from various reduced iron minerals at different redox conditions. OH production was generally observed from the oxidation of reduced iron minerals, following the order: mackinawite (FeS) > reduced nontronite (iron-bearing smectite clay) > pyrite (FeS2) > siderite (FeCO3). Structural Fe2+ and dissolved O2 play critical roles in OH production from reduced iron minerals. OH production increases with decreasing pH, and Cl? has little effect on this process. More importantly, dissolved organic matter significantly enhances OH production, especially under O2 purging, highlighting the importance of this process in ambient environments. This sunlight-independent pathway in which OH forms during oxidation of reduced iron minerals is helpful for understanding the degradation and transformation of various inorganic and organic pollutants in the redox-fluctuation environments. 相似文献
39.
trans-Pd(NO3)H(PCy3)2 (I) when treated with Et4NCl forms the hydride trans-PdClH(PCy3)2 which in turn reacts with AgPF6 in acetonitrile to give trans-[PdH(CH3CN)(PCy3)2]PF6 (III). Both I and III react smoothly with acetylenes containing one electron-withdrawing group to give alkenyl products. The geometry of the resulting alkenyl ligand implies that cis addition has occurred and that the hydridic hydrogen adds to the acetylenic carbon containing the electron-withdrawing group.Acetylenes containing two electron-withdrawing groups give mixtures from which both alkenyl and zerovalent acetylene compounds can sometimes be isolated. In the presence of proton sponge, monosubstituted acetylenes still give alkenyl products while those substituted with two electron-withdrawing groups give the zerovalent products in good yield. The relevance of these results to an understanding of the nature of the migratory insertion reaction is discussed. 相似文献
40.
Components, of the magnetizability tensor for the B1Σ+u and a 3Σ+g states ot the hydrogen molecule have been calculated for fixed bond lengths near equilibrium. Explicitly correlated “generalised James-Coolidge” type wavefunctions were used. It is found thilt in the B 1Σ+u state the molecular magnetizability is a positive quantity. 相似文献