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981.
N. Shigeta H. Matsuoka A. Osa M. Koizumi M. Izumo K. Kobayashi K. Hashimoto T. Sekine R. M. Lambrecht 《Journal of Radioanalytical and Nuclear Chemistry》1996,205(1):85-92
No-Carrier-Added186Re was produced using the186W(p,n)186Re nuclear reaction with 13.6 MeV protons on thick targets of 99.79% isotopically enriched186WO3. The theoretical excitation functions for producing186Re, and possible radionuclidic impurities of182Re,183Re, and184Re were calculated using the ALICE code. Cross-sections of the186W(p,n)186Re reaction were measured up to 20 MeV using the stacked target method with thin foils of natural composition tungsten metal. The experimental and theoretical excitation functions were in good agreement. Targetry used at the TIARA cyclotron, and a radiochemical separation scheme for186Re are described. 相似文献
982.
Hiroaki Tada Tetsuji Ishida Ayako Takao Seishiro Ito Sudip Mukhopadhyay Tomoki Akita Koji Tanaka Hisayoshi Kobayashi 《Chemphyschem》2005,6(8):1537-1543
TiO2 particles loaded with silver nanoparticles with a mean diameter of 1.5 nm exhibit a high photocatalytic activity (84 % conversion after 1 h irradiation) for the reduction of nitrobenzene to aniline with 100 % selectivity in the presence of CH3OH (concentration=100 mM). High-resolution transmission electron microscopic studies of Pt-photodeposited Ag/TiO2 demonstrate that the Ag nanoparticles act as reduction sites in the photocatalytic reaction. Both spectroscopic measurements and density functional theory (DFT) calculations reveal that nitrobenzene is selectively adsorbed onto the Ag surfaces of Ag/TiO2 via partial electron transfer from Ag to nitrobenzene, whereas the interaction between aniline and Ag/TiO2 is weak. The kinetic analysis indicates that the recombination between the electrons flowing into the Ag nanoparticle and the holes left in the TiO2 valence band is significantly suppressed, particularly in the presence of CH3OH. The high activity and selectivity in the present Ag/TiO2-photocatalyzed reduction are rationalized in terms of the charge separation efficiency, the selective adsorption of the reactants on the catalyst surfaces, and the restriction of the product readsorption. 相似文献
983.
Fumihisa Kobayashi Tatsuro Sawada Yoshitoshi Nakamura Makoto Ohnaga Mutui Godliving Tomoo Ushiyama 《Applied biochemistry and biotechnology》1998,69(3):177-189
Steam explosion pretreatment of potato for the efficient production of alcohol was experimentally studied. The amount of water-soluble
starch increased with the increase of steam pressure, but the amounts of methanol-soluble material and Klason lignin remained
insignificant, regardless of steam pressure. The potatoes exploded at high pressure were hydrolyzed into a low molecular liquid
starch, and then easily converted into ethanol by simultaneous saccharification and fermentation using mixed microorganisms:
an amylolytic microorganism,Aspergillus awamori, and a fermentation microorganism,Saccharomyces cerevisiae. The maximal ethanol concentration was 4.2 g/L in a batch culture at 15 g/L starch concentration, and 3.6 g/L in a continuous
culture fed the same starch concentration. In the fed-batch culture, the maximal ethanol concentration increased more than
twofold, compared to the batch culture. 相似文献
984.
Junji Furukawa Eiichi Kobayashi Shiro Nagata T
hei Moritani 《Journal of polymer science. Part A, Polymer chemistry》1974,12(8):1799-1807
13C NMR spectra of acrylic monomers complexed with a Lewis acid were measured and their electronic structures discussed in relation to their alternating copolymerizability. The β-carbon of acrylonitrile and methacrylonitrile showed a downfield shift due to the complex formation with the Lewis acid, while the α-carbon showed an upfield shift and the nitrile carbon showed no significant shift. The degree of shift of olefinic carbons decreased in the following order: AlCl3 > EtAlCl2 > Et1.5AlCl1.5 > Et2AlCl > SnCl4, EtOAlCl2 > Et(EtO)AlCl, which seems to run parallel to the Lewis acidity and acid strength. On the other hand, the chemical shift of olefinic carbons of methyl acrylate, methyl methacrylate, and olefinic diesters was influenced little by complex formation with Lewis acids, whereas the carbonyl and alkoxyl carbons were deshielded significantly by the complex formation. These results are discussed in terms of electron distribution on the carbons and an alternating polymerization mechanism. 相似文献
985.
Xu P Uyama H Whitten JE Kobayashi S Kaplan DL 《Journal of the American Chemical Society》2005,127(33):11745-11753
Nanoscale surface patterning and polymerization of caffeic acid on 4-aminothiophenol-functionalized gold surfaces has been demonstrated with dip pen nanolithography (DPN). The diphenolic moiety of caffeic acid can be polymerized by biocatalysis with laccase or horseradish peroxidase. In the present study, the DPN patterned features were polymerized in situ through the use of the peroxidase. Using samples prepared by DPN, microcontact printing, and adsorption on macroscopic substrates, the products were characterized by electrostatic force microscopy (EFM), MALDI-TOF, X-ray photoelectron spectroscopy (XPS), UV-vis, and FT-IR. The in situ surface polymerization resulted in the formation of a quinone structure, while the phenyl ester formed in bulk polymerization reactions was not detected. A different coupling site was observed when comparing the polymers obtained from solution (bulk) vs the surface DPN reactions. The structural differences were attributed to surface-induced pre-organization and orientation of the monomers prior to the enzymatic polymerization step. The results of this study expand the application of DPN technology to surface modification and surface chemistry reactions wherein stereo-regularity and regioselectivity can be exploited. 相似文献
986.
987.
Kazuyoshi Tanaka Hiromi Kobayashi Mayumi Okada Masahiro Kobashi Tokio Yamabe 《International journal of quantum chemistry》1992,42(1):45-54
Electronic-phase transition associated with the singlet instability problem of the Hartree-Fock solution of the extended system is studied employing the metallic trans-polyacetylene. Concerning the eigenstates of the stability matrix set up for the crystal orbitals at the Fermi level, classification of the electronic phases is attempted and the origin of their emergence in relation to the interelectronic interaction is discussed. 相似文献
988.
Ishikawa S Hamada T Manabe K Kobayashi S 《Journal of the American Chemical Society》2004,126(39):12236-12237
Catalytic asymmetric hydroxymethylation of silicon enolates has been achieved. In this reaction, an aqueous solution of formaldehyde can be used to realize an easy and safe procedure, and high enantioselectivities have been obtained. This is the first example of catalytic asymmetric reactions in aqueous media with a chiral scandium complex. 相似文献
989.
Reversed-phase,high-performance,thin-layer chromatography of metal tetrakis (p-tolyl) porphine complexes on octadecylbonded stationary phase 总被引:1,自引:0,他引:1
Summary The metal complexes ofmeso-tetrakis (p-tolyl) porphine (TTP) are chromatographed on octadecyl-bonded silica gel thin-layer with various organic solvents of relatively high polarity used as the eluent. The mobility of the metal-TTP complex depends on its centralmetal, increasing in the order of Cu(II)<Pd(II)NI(II)<TTP free acid<V(IV) as vanadyl<Zn(II)<Mg(II), although some irregularities are found with the different developing solvents used. The concept of Hildebrand's solubility parameter is applied to the discussion of the mobility of each compound, on the solvents used as the developer. Successful separation of the TTP compounds is performed by using a mixture of acetone and acetonitrile as the developer, although the Ni- and Pd-complexes are not completely resolved. 相似文献
990.
Shoji Takigami Fumihiko Kobayashi Yoshio Nakamura 《Journal of polymer science. Part A, Polymer chemistry》1987,25(1):63-75
Nylon 6 film and acrylic acid grafted nylon 6 (GN) membrances were reacted with paraformaldehyde and lactic acid in the presence of acid catalysts. Decrystallized nylon 6 (DN) and decrystallized grafted nylon 6 (DGN) membranes were thus obtained. The cross sections of GN and DGN membranes were observed by a transmission electron microscope. Branch poly(acrylic acid) penetrated toward the center of the membrane and deposited homogeneously within the membrane as the extent of grafting exceeded about 100%. The reverse osmosis of DN and DGN membranes was investigated. The water permeability through the membranes was improved by the decrystallization reaction. DGN membranes with more than 100% grafting show high values of the salt rejection (Rs) as compared with DN and DGN membranes with about 50% grafting, especially at the region of the high hydraulic permeability coefficient of water (K). The relationships among Rs, K, and the volume fraction of water (H) are discussed by considering the results of the decrystallization reaction and electron microscopy. 相似文献