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801.
Akutagawa T Shitagami K Nishihara S Takeda S Hasegawa T Nakamura T Hosokoshi Y Inoue K Ikeuchi S Miyazaki Y Saito K 《Journal of the American Chemical Society》2005,127(12):4397-4402
Nanoscale molecular rotors that can be driven in the solid state have been realized in Cs2([18]crown-6)3[Ni(dmit)2]2 crystals. To provide interactions between the molecular motion of the rotor and the electronic system, [Ni(dmit)2]- ions, which bear one S=1/2 spin on each molecule, were introduced into the crystal. Rotation of the [18]crown-6 molecules within a Cs2([18]crown-6)3 supramolecule above 220 K was confirmed using X-ray diffraction, NMR, and specific heat measurements. Strong correlations were observed between the magnetic behavior of the [Ni(dmit)2]- ions and molecular rotation. Furthermore, braking of the molecular rotation within the crystal was achieved by the application of hydrostatic pressure. 相似文献
802.
Yoshitsugu Hasegawa Rieko Matsuda Masahiko Kisa Mamoru Iso 《Journal of inclusion phenomena and macrocyclic chemistry》2002,42(1-2):33-38
The intercalation and deintercalation of N, N-dimethyl-1-phenylethylamine (N,N-amine) into -zirconium phosphate was investigated by pH titration. N,N-amine was taken up easily in one step to give a new phaseZr(HPO4)(HPO4·N,N-amine) · H2O, which was characterized by X-ray diffractometry, IR spectroscopy, and thermal analysis. Therelease of N,N-amine from the solid was found to be irreversible due to structural changes in both the intercalation and deintercalation reactions. 相似文献
803.
Ojima I Vu AT Lee SY McCullagh JV Moralee AC Fujiwara M Hoang TH 《Journal of the American Chemical Society》2002,124(31):9164-9174
The reaction of a 1,6-enyne with a hydrosilane catalyzed by Rh(acac)(CO)(2), Rh(4)(CO)(12), or Rh(2)Co(2)(CO)(12) under ambient CO atmosphere or N(2) gives 2-methyl-1-silylmethylidene-2-cyclopentane or its heteroatom congener in excellent yield through silylcarbocycization (SiCaC) process. The same reaction, but in the presence of a phosphite such as P(OEt)(3) and P(OPh)(3) under 20 atm of CO, affords the corresponding 2-formylmethyl-1-silylmethylidene-2-cyclopentane or its heteroatom congener with excellent selectivity through carbonylative silylcarbocycization (CO-SiCaC) process. The SiCaC reaction has also been applied to a 1,6-enyne bearing a cyclohexenyl group as the alkene moiety and a 1,7-enyne system. The functionalized five- and six-membered ring systems obtained by these novel cyclization reactions serve as useful and versatile intermediates for the syntheses of natural and unnatural heterocyclic and carbocyclic compounds. Possible mechanisms for the SiCaC and CO-SiCaC reactions as well as unique features of these processes are discussed. 相似文献
804.
Yoshitake Y Misaka J Abe M Yamasaki M Eto M Harano K 《Organic & biomolecular chemistry》2003,1(7):1240-1249
Carboxylic acid host compounds (3) having a phenanthrene-condensed bicyclo[2.2.1]hept-2-en-7-one skeleton have been synthesized by the [4 + 2]pi cycloaddition of phencyclone (1a) with 2-alkenoic acids (2) and their inclusion behavior was investigated. The endo [4 + 2]pi cycloadducts (3) enclathrated alcohols and ethers besides aromatics and ketones. The X-ray crystallographic analysis of the inclusion compound (3ac-dioxane) of the endo [4 + 2]pi cycloadduct (3ac) of phencyclone and trans 2-butenoic acid (2c) indicated that dioxanes are located at the opposite side of the bridged carbonyl of the bicyclo[2.2.1]hept-2-en-7-one moiety, in which the O-H...O and C-H...O hydrogen bonds play an important role in the inclusion complex formation. Similarly, a pair of 3-pentanone molecules were included in the endo [4 + 2] pi cycloadduct (3ae) of 1a and cinnamic acid (2e). In both cases, the hosts are linked by the edge-to-face interaction between the phenanthrene and phenyl rings and the "bidentate" C-H...O hydrogen bonds between the phenanthrene-ring hydrogens and the bridged carbonyl or the carboxylic carbonyl group. The endo [4 + 2] pi cycloadduct (3bl) of tetracyclone (1b) and acrylamide (2l) also showed a wide-range inclusion behavior, in which alcohols are included by making a hydrogen-bond loop with the amide groups. The inclusion behavior of the carboxylic acid Diels-Alder hosts is discussed on the basis of the single crystal X-ray analysis, thermal analysis and semiempirical molecular orbital calculation data. 相似文献
805.
Masahiro Hasegawa Kunio Arai Shozaburo Saito 《Journal of polymer science. Part A, Polymer chemistry》1987,25(12):3231-3239
The encapsulation of fine inorganic powder was carried out with the soapless emulsion polymerization of methyl methacrylate in water in the presence of the powder, a layer of surfactant being adsorbed. The powder used was titanium dioxide. Surfactants added prior to the polymerization were sodium dodecyl sulfate, dodecyltrimethyl ammonium bromide, and polyoxyethylene sorbitan mono-oleate. The encapsulation state of the powder with polymer was closely related to the amount of surfactant adsorbed on the powder; and an amount of adsorption above a certain value was necessary for uniform encapsulation. Ionic surfactants were more useful than nonionic in the surfactants used, and could be adsorbed utilizing the electrostatic interaction between powder and the ionic end group. The combination of electric charges between the ionic end groups of surfactant and initiator was found to influence the molecular weight of capsulating polymer. 相似文献
806.
Seiji Kurihara Masaki Moritsugu Sun-nam Kim Takamasa Nonaka 《European Polymer Journal》2007,43(12):4951-4960
A photochemically tunable photonic crystal was prepared by infiltration of the polymer liquid crystal (LC) having azo-chromophores in a SiO2 inverse opal structure. The SiO2 inverse opal film infiltrated with the polymer LC reflected a light corresponding to the periodicity as well as the refractive indices of the inverse opal structure. Linearly polarized light irradiation caused the shift of the reflection band to longer wavelength more than 15 nm. This is caused by the formation of uniaxially anisotropic molecular orientation of the polymer LC. The switched state was stable under interior light, and reversible switching of the reflection band can be achieved by the linearly and circularly polarized light irradiation. This photoswitching property will be suitable not only for various optical materials, but also for introduction of defects in the photonic crystals. 相似文献
807.
Somei M Yamada F Kurauchi T Nagahama Y Hasegawa M Yamada K Teranishi S Sato H Kaneko C 《Chemical & pharmaceutical bulletin》2001,49(1):87-96
Application of regioselective nucleophilic substitution reactions of 1-hydroxytryptamines to novel and simple syntheses of serotonin (1a), N-methylserotonin (1b), bufotenine (1c), 5-methoxy-N-methyltryptamine (2a), bufobutanoic acid (3a), N-(indol-3-yl)methyl-5-methoxy-N-methyltryptamine (4), and lespedamine (5) are described. Effective syntheses of 5-benzyloxytryptamine and 1-methoxy-2-oxindoles are also reported. 相似文献
808.
Fusae Suzuki Yasuzo Suzuki Hachiro Nakanishi Masaki Hasegawa 《Journal of polymer science. Part A, Polymer chemistry》1969,7(8):2319-2331
The solid-state photopolymerization of phenylene diacrylic acid (PDA) and its derivatives was studied as an application of solid-state photodimerization of cinnamic acid to photopolymerization of corresponding bifunctional molecule which has two cinnamic units in a single molecule. p- and m-PDA, and their esters and amides were prepared and investigated with respect to their photopolymerizability. Many of them have been found to polymerize into linear high polymers with the cyclobutane rings in the main chain on irradiation by ultraviolet or visible light. The polymerization process, the structure of the polymers, and their general properties were investigated in several ways. All the polymers are very similar to poly-2,5-distyrylpyrazine and poly-1,4-bis(β-pyridyl-2-vinyl) benzene with respect to their polymerization behavior, polymer structure, and some polymer properties: these polymers are soluble in a limited number of solvents, they have a high melting point and an extremely high crystallinity. On the basis of chemical behavior of poly-PDA and its phenyl ester the possible steric configurations of these polymers are discussed. It is demonstrated for the PDA series that solid-state dimerization can be generally extended to solid-state photopolymerization of the compound having two dimerizable units in a single molecule, although the crystal structure renders polymerization impossible in certain cases. 相似文献
809.
Maeda Y Miyashita J Hasegawa T Wakahara T Tsuchiya T Nakahodo T Akasaka T Mizorogi N Kobayashi K Nagase S Kato T Ban N Nakajima H Watanabe Y 《Journal of the American Chemical Society》2005,127(35):12190-12191
The reversible and regioselective reaction of La@C82 with cyclopentadiene was carried out. The activation and thermodynamic parameter of the retro-reaction was estimated from the Arrhenius plots of the rate constants. 相似文献
810.
T. Sakurai X.-D. Wang Q.K. Xue Y. Hasegawa T. Hashizume H. Shinohara 《Progress in Surface Science》1996,51(4):263-408
Scanning tunneling microscopy investigations of adsorption and film growth of various fullerenes on semiconductor and metal surfaces are reviewed. The fullerenes being studied are C60, C70, C84, Sc@C82 and Y@C82 and the substrates being used for adsorption are Si (111), Si (100), Ge (111), GaAs (110), GaAs (001), Au (111), Au (110), Au (100), Cu (111) and Ag (111) surfaces. 相似文献