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71.
72.
Shin-ichi Kondo Kimihiro Endo Jun Iioka Keisuke Sato Yuka Matsuta 《Tetrahedron letters》2017,58(43):4115-4118
We have successfully prepared 5-(2-phenylethynyl)isophathalilc acid as a signaling unit and the corresponding derivatives for an anion receptor 2 and a barbiturate receptor 4. Receptor 2 showed characteristic UV–vis changes and dramatic fluorescence quenching upon the addition of anions and receptor 4 showed UV–vis and an OFF-ON fluorescence changes upon the addition of dibutylbarbituric acid based on the diphenylethyne moiety. 相似文献
73.
Makoto Okawara Takeshi Endo Eisuke Fujiwara Takayoshi Hirose 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(4):441-459
Polymers containing 1,4-dihydronicotinamide (P-NAH) alloxan (P-A), and viologen (P-V2+) moieties were synthesized and characterized. P-NAH reduced various organic substances such as lipoic acid, alloxan, and viologens and also immobilized quinone mediated by alloxan. P-A was reduced to the polymer-bearing alloxan radical and the dialuric acid structure without crosslinks by one- and two-electron reduction, respectively, and P-A also mediated the redox reaction occurring between aqueous and organic (water-immiscible) layers. P-V2+ was converted to the stable viologen radical reversibly by one-electron reduction. Electric potentials and currents on photo-reduction of P-V2+ and catalytic behavior of P-V2+ in the reduction of carbonyl compounds were examined. 相似文献
74.
Luise Oemisch Kai-Uwe Goss Satoshi Endo 《Analytical and bioanalytical chemistry》2013,405(8):2567-2574
Experimental determination of oil-water partition coefficients often poses difficulties associated with emulsion formation. The aim of this work was to find an appropriate technique for determination of oil–water partition coefficients of polar, nonvolatile compounds. Two different methods were tested. The first method used a “silicone membrane equilibrator.” For the second method, solid-phase microextraction (SPME) fibers with a polyacrylate (PA) coating were used as a passive sampler. With both methods, oil–water partition coefficients for 14 compounds with polar functional groups were determined at 37 °C with good repeatability (standard deviation 0.11 log units or lower). The partition coefficients determined with the silicone membrane equilibrator method ranged from 0.50 to 3.49 log units. The oil–water partition coefficients obtained with the PA-SPME passive sampling approach were significantly higher than those obtained with the silicone membrane equilibrator method for nine of 14 compounds. The differences were up to 0.39 log units (i.e., a factor of 2.5). Additional experiments suggested that this difference occurred because the sorption properties of the PA fibers used were influenced by the surrounding phase, e.g., through swelling of the polymer phase. Therefore, the SPME passive sampling method using PA fibers seems to be less reliable, whereas the silicone membrane equilibrator method was found to be a convenient technique for the determination of oil–water partitioning. 相似文献
75.
Rod-like cellulose nanowhiskers and spherical cellulose nanoparticles were prepared from wood-pulp-derived cellulose powder by mechanical refining processes such as high-pressure homogenization (HPH) and ball-milling (BM). The nanowhiskers obtained by the HPH method were found to be 200–500 nm long and 11–16 nm wide. The diameters of the nanoparticles were in the range 40–200 nm, depending on the BM time, and were reduced to 25–50 nm after extra HPH. By adjusting the BM time, cellulose nanoparticles having different polymorphs with similar morphologies were prepared. The X-ray diffraction patterns revealed the recrystallization of cellulose I (1 h of BM time) or cellulose II (4–8 h of BM time) in ball-milled nanoparticles after water washing and solvent exchange treatments. The nanowhisker widths derived from the specific surface areas (SSA) by adsorption methods such as Congo red dye, nitrogen, and water vapor, sorptions were in agreement with those obtained from transmission electron microscopy and atomic force microscopy images. Similar SSA values were obtained for micro- and nano-scale cellulose materials using water vapor adsorption methods, and the SSAs of nanoparticles obtained by different adsorption methods are also discussed. 相似文献
76.
F. Khoerunnisa D. Minami T. Fujimori S. Y. Hong Y. C. Choi H. Sakamoto M. Endo K. Kaneko 《Adsorption》2014,20(2-3):301-309
We tuned the electronic properties of single wall carbon nanotube (SWCNT) with intercalation of naphthalene derivatives (NDs) having different electron donor or acceptor property in the SWCNT bundles. Characterization of the adsorbed SWCNT with Raman spectroscopy and electrical conductivity measurement clearly indicate the charge transfer interaction of ND molecules with SWCNT. Also X-ray diffraction supports the intercalation of ND molecules in the interstitial spaces and groove sites of SWCNT bundle. Intercalation of ND molecules enhances remarkably the CO2 adsorptivity, which can be ascribed to the key importance of the interaction of the quadrupole moment of CO2 with the local electrical field on the SWCNT induced by the charge transfer interaction. 相似文献
77.
Hiroyuki Muramatsu Kazunori Fujisawa Yong-Il Ko Kap-Seung Yang Takuya Hayashi Morinobu Endo Cheol-Min Yang Yong Chae Jung Yoong Ahm Kim 《催化学报》2014,35(6):864-868
Nanoscale defects in the outer tube to preserve the electrical and optical features of the inner tube can be engineered to exploit the intrinsic properties of double walled carbon nanotubes (DWCNTs) for various promising applications. We demonstrated a selective way to make defects in the outer tube by the fluorination of DWCNTs followed by the thermal detachment of the F atoms at 1000 °C in argon. Fluorinated DWCNTs with different amounts of F atoms were prepared by reacting with fluorine gas at 25, 200, and 400 °C that gave the stoichiometry of CF0.20, CF0.30, and CF0.43, respectively. At the three different temperatures used, we observed preservation of the coaxial morphology in the fluorinated DWCNTs. For the DWCNTs fluorinated at 25 and 200 °C, the strong radial breathing modes (RBMs) of the inner tube and weakened RBMs of the outer tube indicated selective fluorine attachment onto the outer tube. However, the disappearance of the RBMs in the Raman spectrum of the DWCNTs fluorinated at 400 °C showed the introduction of F atoms onto both inner and outer tubes. There was no significant change in the morphology and optical properties when the DWCNTs fluorinated at 25 and 200 °C were thermally treated at 1000 °C in argon. However, in the case of the DWCNTs fluorinated at 400 °C, the recovery of strong RBMs from the inner tube and weakened RBMs from the outer tube indicated the selective introduction of substantial defects on the outer tube while preserving the original tubular shape. The thermal detachment of F atoms from fluorinated DWCNTs is an efficient way to make highly defective outer tubes for preserving the electrical conduction and optical activity of the inner tubes. 相似文献
78.
79.
Eiichi Sato Tsutomu Yokozawa Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》1996,34(4):669-672
Polyadditions of 1,4-benzenedithiol (BDT) to bis(alkoxyallene)s, such as 1,4-bis(allenyloxy)xylene (3) and 1,4-bis(allenyloxy) benzene (4) , were carried out in benzene at 25°C by irradiation with a high pressure mercury lamp. Thiol groups were added to the terminal double bonds of the allenyloxy groups selectively to afford polymers containing reactive carbon–carbon double bonds in the main chain, similar to the radical polyadditions using azobis(isobutyronitrile) (AIBN). The molecular weight of the polymer obtained from BDT and 3 was 10 times higher than that of the polymer produced in the radical polyaddition with AIBN; whereas the molecular weight of the polymer from BDT and 4 was similar to that in the radical polyaddition, probably because of poor solubility of 4 and the polymer toward benzene. The geometrical structure of carbon–carbon double bonds in the polymer isomerized from an E to Z structure with reaction time by virtue of both the addition elimination of thiyl radical to the double bonds and the UV irradiation. © 1996 John Wiley & Sons, Inc. 相似文献
80.