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排序方式: 共有1188条查询结果,搜索用时 281 毫秒
941.
Akutagawa T Jin R Tunashima R Noro S Cronin L Nakamura T 《Langmuir : the ACS journal of surfaces and colloids》2008,24(1):231-238
Clusters based on the mixed-valence gigantic inorganic ring [Mo154O462H14(H2O)70]14- ({Mo154}-ring) and dimethyldioctadecylammonium (DODA) were combined to form novel molecular assemblies of an inorganic-organic hybrid molecular system as Langmuir-Blodgett (LB) and cast films. (DODA)20[Mo154O462H8(H2O)70] (2) was prepared by cation exchange and was characterized by a combination of thermogravimetry, IR, UV-vis-NIR, 1H NMR, and XRD measurements. The salt 2 was soluble in common organic solvents, and the chemical stability of {Mo154}-ring encapsulated by DODA cationic surfactants in CHCl3 was found to be higher than that of the "native" sodium salt of the {Mo154}-ring in H2O. Uniform spherical vesicle-like molecular assemblies of (DODA)20[Mo154O462H8(H2O)70] were observed in dilute THF, whose average diameter of 95 nm and a normalized variance of 5.7% were confirmed by a X-ray small-angle scattering. Deposition of 2 as a cast film showed circular domains with a typical diameter of approximately 100 nm, indicating possible similarities between solution and surface-deposited structures. The resulting LB films of salt 2 were transferred from an acidic buffer subphase with pH = 1.5 onto mica, giving a two-dimensional film surface with a unity transfer ratio. Further, the electronic absorption spectra of the LB multilayer were consistent with the classic type II mixed-valence MoV/MoVI electronic state well know for molybdenum blue {Mo154}-ring systems, and it appears that on the surface the plane of the {Mo154}-ring is approximately parallel to the substrate surface, as indicated by polarized electronic spectra, while the alkyl chains of DODA were relatively normal to the substrate surface. Therefore, the layer between the {Mo154}-rings and DODA cations was alternately stacked along the direction of film propagation. Finally, it was found that the surface morphology of the cast and LB films was determined by the molecular assembly of (DODA)20[Mo154O462H8(H2O)70] in solution and the air-water interface, respectively. 相似文献
942.
Tsunashima R Noro S Akutagawa T Nakamura T Kawakami H Toma K 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(27):8169-8176
Fullerene derivative C60TT, which is substituted with the low-molecular-weight organogelator tris(dodecyloxy)benzamide, formed nanowire structures on application of the Langmuir-Blodgett (LB) method. The surface morphology of the C60TT LB film was dependent on the holding time before deposition at a surface pressure of 5 mN m(-1); it changed from a homogeneous monolayer to a bilayer fibrous structure via a fibrous monolayer structure, which was estimated to have dimensions of 1.2 nm in height, 8 nm in width, and 5-10 microm in length. From the structural and spectroscopic data, it is inferred that close packing of the fullerene moiety occurs along with intermolecular hydrogen bonding within the monolayer fibrous structure. The morphological changes in the LB film are explained kinetically by the Avrami theory, based on the decrease in the surface area of the monolayer at the air/water interface. The growth of the quasi-one-dimensional fibrous monolayer structures at holding times from 0 to 0.2 h is considered to be an interface-controlled process, whereas the growth of the quasi-one-dimensional bilayer fibrous structures from 0.2 to 18 h is thought to be a diffusion-controlled process. 相似文献
943.
Prof. Dr. Tomoyuki Mochida 《Chemical record (New York, N.Y.)》2023,23(8):e202300041
Ionic liquids (ILs) are salts with low melting points and are useful as electrolytes and solvents. We have developed ILs containing cationic metal complexes, which form a family of functional liquids that exhibit unique physical properties and chemical reactivities originating from metal complexes. Our study explores the liquid chemistry in the field of coordination chemistry, where solid-state chemistry is currently the main focus. This review describes the molecular design, physical properties, and reactivities of organometallic ILs containing sandwich or half-sandwich complexes. This paper mainly covers stimuli-responsive ILs, whose magnetic properties, solvent polarities, colors, or structures change by the application of external fields, such as light, heat, and magnetic fields, or by reaction with coordinating molecules. 相似文献
944.
Cover Picture: Persistent Dialkylsilanone Generated by Dehydrobromination of Dialkylbromosilanol (Chem. Eur. J. 43/2015)
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945.
X‐ray absorption fine structure study on the role of solvent on polymerization of 3‐hexylthiophene with solid FeCl3 particles
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Tomoyasu Hirai Masanao Sato Makoto Kido Yusuke Nagae Katsuhiro Kaetsu Yudai Kiyoshima Shota Fujii Tomoyuki Ohishi Kevin L. White Yuji Higaki Yasutake Teraoka Maiko Nishibori Kazutaka Kamitani Kenji Hanada Takeharu Sugiyama Ryuichi Sugimoto Kazuhiko Saigo Ken Kojio Atsushi Takahara 《Journal of polymer science. Part A, Polymer chemistry》2015,53(18):2075-2078
946.
Dioxomolybdenum(VI) and dioxotungsten(VI) complexes: efficient catalytic activity for crosslinking reaction in ethylene‐vinyl acetate copolymer/alkoxysilane composites
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Kenta Adachi Shoko Toyomura Yuko Miyakuni Suzuko Yamazaki Kensuke Honda Tomoyuki Hirano 《先进技术聚合物》2015,26(6):597-605
The catalytic performances of several bis(acetylacetonato)metal complexes [Cu(acac)2, Zn(acac)2, TiO(acac)2, VO(acac)2, MoO2(acac)2, and WO2(acac)2] were investigated for the crosslinking reaction via transesterifications in the ethylene‐vinyl acetate copolymer/tetraethoxysilane (EVA/TEOS) composite system by means of dynamic attenuated total reflectance Fourier transform infrared, solvent swelling, and solid‐state 29Si cross polarization/magic angle spinning nuclear magnetic resonance techniques. Results of the kinetic examination revealed that MoO2(acac)2 and WO2(acac)2 exhibited a higher catalytic activity than di‐n‐butyltin(IV) oxide, which is a catalyst most commonly used for the transesterification process in polymer system, but has a toxic effect on the environmental health. And furthermore, the crosslink density and final siloxane network structure of crosslinked EVA/TEOS composites are found to be greatly correlated with the catalyst used. On the basis of the SN2‐Si pathway, a plausible catalytic mechanism of MoO2(acac)2 and WO2(acac)2 was proposed for the crosslinking reaction via transesterifications of the vinyl acetate moieties in EVA backbone with the ethoxysilane groups in one TEOS molecule. The findings in this study may fill the blank in the high performance and environmentally friendly catalyst in the field of the crosslinking reactions in polymer system and provide useful clue for other transesterifications. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
947.
Tomoyuki Takenawa 《Communications in Mathematical Physics》2001,224(3):657-681
A geometric charactrization of the equation found by Hietarinta and Viallet, which satisfies the singularity confinement
criterion but which exhibits chaotic behavior, is presented. It is shown that this equation can be lifted to an automorphism
of a certain rational surface and can therefore be considered to be a realization of a Cremona isometry on the Picard group
of the surface. It is also shown that the group of Cremona isometries is isomorphic to an extended Weyl group of indefinite
type. A method to construct the mappings associated with some root systems of indefinite type is also presented.
Received: 19 March 2001 / Accepted: 11 July 2001 相似文献
948.
Eugen Slobodchikov Shuji Sakabe Tomoyuki Kuge Sakae Kawato Masaki Hashida Yasukazu Izawa 《Optical Review》1999,6(2):149-151
Assembly of a sub-10-fs Ti:sapphire oscillator using only optical components commercially available in catalogues is reported. It was demonstrated that stable sub-10-fs optical pulses near 800 nm can be generated from a Kerr-lens mode locked oscillator equipped with a pair of prisms to compensate group delay dispersions (GDD) in the cavity. For the GDD control in a 10fs-pulse oscillator it was concluded that chirped mirrors are not always necessary, and a pair of prisms is still available. 相似文献
949.
Tomoyuki Yamakami 《Journal of Complexity》1999,15(4):235
This paper studies the complexity of the polynomial-time samplable (P-samplable) distributions, which can be approximated within an exponentially small factor by sampling algorithms in time polynomial in the length of their outputs. The paper shows that common assumptions in complexity theory yield the separation of polynomial-time samplable distributions from the polynomial-time computable distributions with respect to polynomial domination, average-polynomial domination, polynomial equivalence, and average-polynomial equivalence. 相似文献
950.
We produce in an explicit form free generators of the affine \(\mathcal {W}\)-algebra of type A associated with a nilpotent matrix whose Jordan blocks are of the same size. This includes the principal nilpotent case and we thus recover the quantum Miura transformation of Fateev and Lukyanov. 相似文献