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91.
A copper containing Prussian Blue analogue was incorporated into a conducting polypyrrole film. The modified electrode was synthesized through an electrochemical two-step methodology leading to very stable and homogeneous hybrid films. These electrodes were proved to show excellent catalytic properties towards H2O2 detection, with a performance higher than those observed for Prussian Blue and other analogues. Electrochemical impedance spectroscopy experiments demonstrated that the excellent performance of these hybrid films is strongly related to the electronic conductivity of the polymeric matrix that is wiring the copper hexacyanoferrate sites. A glucose biosensor was built-up by the immobilization of glucose oxidase; the sensitivity obtained being higher than other biosensors reported in the literature even in Na+ containing electrolytes. 相似文献
92.
High-quality epitaxial thin films of the ferromagnetic metallic oxide SrRuO3 (SRO) were fabricated by dc-sputtering at high oxygen pressure and their structural and magnetoelectrical properties were carefully studied. The films featured a Curie temperature TC ~ 160 K and a magnetic moment of ~0.7 μB per Ru ion. The temperature dependent magnetization could be well described by the scaling relation M(T) ∝ (TC ? T)β with a critical exponent β = 0.53 over the entire ferromagnetic temperature range. A negative magnetoresistance, MR, on the order of a few percent was found up to room temperature. MR showed a maximum of ~4% right at TC where a kink structure of the resistivity, ρ, at zero field was flattened out on magnetic field application. This ρ contribution could be related to scattering due to orientational disorder of the Ru magnetic moments which become aligned by an external magnetic field. In addition, an equally strong MR effect, related to localization phenomena, could be observed at lower temperature. Particularly, the second MR peak at ~35 K might be related to a Fermi-liquid to non-Fermi-liquid crossover. A scaling behavior dρ/dT ∝ |T ? TC|α was observed only above TC. Here, values for the exponent α ≈ ?0.4 and α ≈ ?1.4 were obtained in zero field and in a field of 9 T, respectively. The commonly observed ρ minimum, appearing at low temperatures (~3 K in the present case), is correlated with the structural disorder of the SRO films and is believed to have its origin in quantum corrections to the conductivity (QCC). 相似文献
93.
Pablo J. Alonso Prof. Dr. Ana B. Arauzo Dr. María Angeles García‐Monforte Dr. Antonio Martín Dr. Babil Menjón Dr. Conrado Rillo Prof. Dr. Milagros Tomás Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(41):11020-11030
Homoleptic perhalophenyl derivatives of divalent nickel complexes with the general formula [NBu4]2[NiII (C6X5)4] [X=F ( 1 ), Cl ( 2 )] have been prepared by low‐temperature treatment of the halo‐complex precursor [NBu4]2[NiBr4] with the corresponding organolithium reagent LiC6X5. Compounds 1 and 2 are electrochemically related by reversible one‐electron exchange processes with the corresponding organometallate(III) compounds [NBu4][NiIII (C6X5)4] [X=F ( 3 ), Cl ( 4 )]. The potentials of the [NiIII (C6X5)4]?/[NiII (C6X5)4]2? couples are +0.07 and ?0.11 V for X=F or Cl, respectively. Compounds 3 and 4 have also been prepared and isolated in good yield by chemical oxidation of 1 or 2 with bromine or the amminium salt [N(C6H4Br‐4)3][SbCl6]. The [NiIII (C6X5)4]? species have SP‐4 structures in the salts 3 and 4 , as established by single‐crystal X‐ray diffraction methods. The [NiII (C6F5)4]2? ion in the parent compound 1 has also been found to exhibit a rather similar SP‐4 structure. According to their SP‐4 geometry, the NiIII compounds (d7) behave as S=1/2 systems both at microscopic (EPR) and macroscopic levels (ac and dc magnetization measurements). The spin Hamiltonian parameters obtained from the analysis of the magnetic behavior of 3 and 4 within the framework of ligand field theory show that the unpaired electron is centered mainly on the metal atom, with >97 % estimated d contribution. Thermal decomposition of 3 and 4 proceeds with formation of the corresponding C6X5? C6X5 coupling compounds. 相似文献
94.
Carolina Zubieta María B. Sierra Marcela A. Morini Pablo C. Schulz Liliana Albertengo María S. Rodríguez 《Colloid and polymer science》2008,286(4):377-384
An adsorbent material made with a silica lamellar mesoporous material treated with chitosan has been proved to be useful to
adsorb both anionic and cationic dyes used in the textile industry. The two tested dyes Tectilon Blue (anionic) and Rhodamine
B (cationic) have different adsorption kinetics reflecting a complex mechanism of the phenomenon. Furthermore, the adsorption
capacity and interaction strength of Tectilon Blue is higher than those of Rhodamine B. Tectilon Blue molecules are situated
with the molecular plane perpendicular to the adsorbent surface, whilst that of the Rhodamine B molecule is flat and parallel
to the surface. The differences may be attributed to the different regions of the adsorbent surface on which the dyes are
adsorbed because of their different electric charge. 相似文献
95.
Carboxylated multiwalled carbon nanotubes (MWCNT-COOH) were used to modify the working electrode surface of different screen-printed electrodes. The effect of this modification on the electrodic characteristics (double layer capacitance, electroactive area and heterogeneous rate constants for the electron transfer) was evaluated and optimized for the cyclic voltammetric determination of p-aminophenol. The enzymatic hydrolysis of p-aminophenylphosphate was employed for the quantification of alkaline phosphatase, one of the most important label enzymes in immunoassays. Finally, ELISA assays were carried out to quantify pneumolysin using this enzymatic system. Results obtained indicated that low superficial densities of MWCNT-COOH (0.03-0.06 μg mm−2) yielded the same electrodic improvements but with better analytical properties. 相似文献
96.
Oliva AI Christmann U Font D Cuevas F Ballester P Buschmann H Torrens A Yenes S Pericàs MA 《Organic letters》2008,10(8):1617-1619
The synthesis of novel tricyclic 1,2,3-triazoles starting from cyclic epoxides via the sequential azidolysis, propargylation and 1,3-dipolar cycloaddition is described. Derivatization by N-arylation reaction and the synthesis of enantiomerically pure compounds is also reported. Some of these compounds exhibit significant affinity for the sigma-1 receptor. 相似文献
97.
98.
Prof. Dr. Javier A. Cabeza Dr. Pablo García-Álvarez Prof. Dr. Mar Gómez-Gallego Laura González-Álvarez Alba D. Merinero Prof. Dr. Miguel A. Sierra 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(36):8635-8642
The reactivity of amidinatotetrylenes of the type E(tBu2bzm)R1 (E=Si, Ge; tBu2bzm=N,N′-bis(tertbutyl)benzamidinate; R1=alkyl or aryl) with the chromium Fischer alkynylcarbene complexes [Cr{C(OEt)C2R2}(CO)5] (R2=Ph; ferrocenyl, Fc) has been studied. At room temperature, two different reaction pathways have been identified: (a) attack of the amidinatotetrylene to the alkynyl C2 atom (γ-attack), which leads to σ-allenyl complexes in which the original Ccarbene atom maintains its attachment to the Cr(CO)5 and OEt groups (compounds 3 ), and (b) attack of the amidinatotetrylene to the Ccarbene atom (α-attack), which ends in σ-allenyl complexes in which the original Ccarbene atom is not attached to the metal atom and has been inserted into an E−N bond of the amidinatotetrylene forming an E-C-N-C-N five-membered ring (compounds 4 ). It has been found that compounds 3 are thermodynamically less stable than their corresponding 4 isomers and that some of the former (E=Ge; R1=CH2SiMe3) can be transformed into the latter upon heating. At high temperatures (>70 °C) the reactions involving bulky amidinatotetrylenes (R1=Mes, tBu) end in the carbene-substitution products [Cr{E(tBu2bzm)R1}(CO)5]. 相似文献
99.
100.
Pablo López-Tarifa Marie-Anne Hervé du Penhoat Rodophe Vuilleumier Marie-Pierre Gaigeot Ursula Rothlisberger Ivano Tavernelli Arnaud Le Padellec Jean-Philippe Champeaux Manuel Alcamí Patrick Moretto-Capelle Fernando Martín Marie-Françoise Politis 《Central European Journal of Physics》2014,12(2):97-102
We use time-dependent density functional theory and Born-Oppenheimer molecular dynamics methods to investigate the fragmentation of doubly ionized uracil in gas phase. Different initial electronic excited states of the dication are obtained by removing electrons from different inner-shell orbitals of the neutral species. We show that shape-equivalent orbitals lead to very different fragmentation patterns revealing the importance of the intramolecular chemical environment. The results are in good agreement with ionion coincidence measurements of uracil collision with 100 keV protons. 相似文献