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排序方式: 共有296条查询结果,搜索用时 9 毫秒
81.
In this paper, we obtain a sufficient condition for the convergence of positive linear operators in Banach function spaces on \({\mathbb {R}}^n\) and derive a Korovkin type theorem for these spaces. Also, we generalized this result via statistical sense. 相似文献
82.
Hiroyuki Hayashi Shota Katayama Rong Huang Kosuke Kurushima Isao Tanaka 《固体物理学:研究快报》2015,9(3):192-196
Undoped n‐ and p‐type tin monoxide (SnO) films have been selectively fabricated by pulsed laser deposition with a Sn target and careful control of oxygen partial pressure. The films are epitaxially grown in optimal growth conditions on yttria‐stabilized zirconia (YSZ) substrates with out‐of‐plane and in‐plane orientation relationships of (001)SnO//(001)YSZ and [110]SnO//[100]YSZ, respectively. Both Seebeck and Hall measurements show consistent results on the carrier types of the films. The electron Hall mobility is approximately 11 cm2/Vs at room temperature and the carrier activation energy is 0.14 eV for the n‐type film. The growth at increased oxygen partial pressure yields p‐type films, demonstrating the selective fabrication of both n‐ and p‐type SnO films without doping. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
83.
Tsukano C Yokouchi S Girard AL Kuribayashi T Sakamoto S Enomoto T Takemoto Y 《Organic & biomolecular chemistry》2012,10(30):6074-6086
The scope and limitations of the platinum catalyzed 7-endo cyclization of internal alkynyl amides were investigated. Substitution of the alkyne with an aryl group gave better results, presumably because it stabilized the transition state. Applying the reaction to a secondary amide, the caprazamycin core was successfully synthesized from commercially available material in eight steps. 相似文献
84.
We consider nonparametric Bayesian estimation of the drift coefficient of a multidimensional stochastic differential equation from discrete-time observations on the solution of this equation. Under suitable regularity conditions, we establish posterior consistency in this context. 相似文献
85.
Dr. Toshifumi Dohi Nobutaka Yamaoka Shota Nakamura Kohei Sumida Koji Morimoto Prof. Dr. Yasuyuki Kita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(6):2067-2075
We have successfully established an efficient route to the core structure of donor–acceptor head‐to‐tail (H–T)‐linked regioregular oligothiophenes, which includes the following key synthetic steps, that is, hypervalent iodine induced direct and regioselective coupling of thiophenes and the use of the obtained bithiophenes as excellent coupling substrates for the Suzuki and Stille couplings. The versatility of this new approach is highlighted in the dramatic improvement of the yield (ca. 59 % overall yield) of MK‐2, a high‐performance organic dye, for photovoltaic applications. 相似文献
86.
Uchiyama S Ohshima A Nakamura S Hasegawa J Terui N Takayama SJ Yamamoto Y Sambongi Y Kobayashi Y 《Journal of the American Chemical Society》2004,126(45):14684-14685
The complete thermal-unfolding profiles of both oxidized and reduced forms of cytochrome c551 (PA) from mesophilic Pseudomonas aeruginosa and cytochrome c552 (HT) from thermophilic Hydrogenobacter thermophilus were obtained by the newly developed pressure-proof cell compartment installed in a circular dichroic spectrometer, which facilitates protein thermal-unfolding experiments up to 180 degrees C. The thermodynamic cycle, which relates protein stability and redox function, indicated that the redox potentials of PA and HT in the native state are regulated by the stability of the oxidized proteins rather than by that of the reduced ones. 相似文献
87.
Naoki Hayakawa Kazuya Sadamori Shota Tsujimoto Prof. Dr. Miho Hatanaka Prof. Dr. Tomonari Wakabayashi Prof. Dr. Tsukasa Matsuo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(21):5859-5863
The reaction of the bulky diphosphenes (Rind)P=P(Rind) ( 1 ; Rind=1,1,3,3,5,5,7,7-octa-R-substituted s-hydrindacen-4-yl) with two molecules of N-heterocyclic carbene (NHC; 1,3,4,5-tetramethylimidazol-2-ylidene) resulted in the quantitative formation of the NHC-bound phosphinidenes NHC→P(Rind) ( 2 ), along with the cleavage of the P=P double bond. The reaction times are dependent on the steric size of the Rind groups (11 days for 2 a (R=Et) and 2 h for 2 b (R=Et, Me) at room temperature). The mechanism for the double bond-breaking is proposed to proceed via the formation of the NHC-coordinated, highly polarized diphospehenes 3 as an intermediate. Approach of a second NHC to 3 induces P−P bond cleavage and P−C bond formation, which proceeds through a transition state with a large negative Gibbs energy change to afford the two molecules of 2 , thus being the rate-determining step of the overall reaction with the activation barriers of 80.4 for 2 a and 29.1 kJ mol−1 for 2 b . 相似文献
88.
Shota Yamada Dr. Takeshi Matsumoto Prof. Dr. Ho-Chol Chang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(35):8268-8278
The oxidation of [MII(3,5-DTBCat)(DTBbpy)] (M=Ni ( [Ni] ), Pd ( [Pd] ), and Pt ( [Pt] ); 3,5-DTBCat=3,5-di-tert-butylcatecholato; DTBbpy=4,4′-di-tert-butyl-2,2′-bipyridine) afforded the dimeric {[NiII(3,5-DTBSQ)(DTBbpy)](PF6)}2 ( {[Ni](PF6)}2 ; 3,5-DTBSQ=3,5-di-tert-butylsemiquinonato) and monomeric semiquinonato (SQ) complexes [MII(3,5-DTBSQ)(DTBbpy)](PF6) (M=Pd ( [Pd](PF6) ) and Pt ( [Pt](PF6) )). The negative solvatochromic properties of the SQ complexes allowed us to estimate the relative order of their dipole moments: [Pd](PF6) > [Pt](PF6) > {[Ni](PF6)}2 . The complexes [Pd](PF6) and [Pt](PF6) adopt monomeric structures and are stable in CH2Cl2 and toluene, whereas they gradually disproportionate at room temperature to [M] and 3,5-di-tert-butylbenzoquinone (3,5-DTBBQ) in polar solvents such as THF, MeOH, EtOH, DMF, or DMSO. The results of spectroscopic studies suggested that the oxidized nickel complex adopts a monomeric structure ( [Ni](PF6) ) in CH2Cl2, but a dimeric structure ( {[Ni](PF6)}2 ) in the other investigated solvents. In polar solvents, {[Ni](PF6)}2 may disproportionate to [Ni] and 3,5-DTBBQ at 323 K, thereby demonstrating a significant solvent- and metal-dependence in temperature. The relative activities of {[Ni](PF6)}2 and [M](PF6) toward disproportionation are related to the electrochemically estimated Kdis values in CH2Cl2 and DMF. The present work demonstrates that solvent polarity and the dipole moments of the SQ complexes promote disproportionation, which can be controlled by a judicious choice of the metal ion, solvent, and temperature. 相似文献
89.
Malval JP Suzuki S Morlet-Savary F Allonas X Fouassier JP Takahara S Yamaoka T 《The journal of physical chemistry. A》2008,112(17):3879-3885
The photophysical properties of a series of 1,8-naphthalimide photoacid generators were studied by steady state fluorescence and phosphorescence spectroscopy. Emission and excitation anisotropies, triplet quantum yields in polar and nonpolar solvent and photoacid generation were evaluated. The singlet excited state exhibits a low polarity and is strongly deactivated by an efficient intersystem crossing process. In protic solvent, a homolytic singlet cleavage of the N-O bond occurs and leads to the acid production. The existence of a triplet state close to the singlet state was clearly evidenced. The presence of close singlet excited states is supported by fluorescence anisotropy and picosecond laser spectroscopy experiments. Results of DFT calculations well confirm the experimental contentions and yield important information about the cleavage process involved in such compounds. 相似文献
90.
Takeo Ito Shota Morimoto Shin-ichi Fujita Kazuo Kobayashi Seiichi Tagawa Sei-ichi Nishimoto 《Chemical physics letters》2008,462(1-3):116-120
Radical species generated from the reactions of a basic amino acid, l-lysine (Lys), with hydroxyl radicals (OH) and sulfate radical anion () have been detected by the method of pulse radiolysis. On the basis of electron transfer reactivities toward tetranitromethane (TNM), it was demonstrated that reducing carbon-centered radicals are generated as a result of hydrogen abstraction from CH2 of Lys with a G-value of 1.9 × 10−7 mol J−1. On the other hand, direct oxidation of l-Lys by formed a transient species with different spectroscopic properties, most likely, the ε-N-centered Lys radical. 相似文献