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181.
M. Asghar A. Emsallem Nils G. Sjöstrand 《Zeitschrift für Physik A Hadrons and Nuclei》1977,282(4):375-381
The thermal neutron induced charged particle spectroscopy on58, 59, 61Ni (target nuclei) was done at the 87 m thermal neutron curved guide of the Grenoble high flux reactor. In the59Nu(n, α)56Fe reaction two lines showed up corresponding toα-particle transitions to the ground and first excited states in56Fe with σα0=13.1±1.1 b and σα1 =0.188±0.01 b. A value of σγα≦13 mb was obtained for the two-step59Ni(n, γα)56Fe reaction. The technique to unfold theγα-spectrum and to get information on the primary low energyγ-rays is given and the present and our previous data on the143Nd(n, γα)140Ce reaction are analysed. For the59Ni(n, p)59Co reaction p0=1.34±0.18b,σ p1<0.30 b were determined. The cross-sections for the58Ni(n,α)55Fe and61Ni(n,α)58Fe reactions were σα0≦30 Μb and σα0≦30 Μb respectively; these andσ p1upper limit value are about 20–1500 times lower than the existing data. The other results are compared with the existing data and the differences are explained. The experimental data are compared with the values obtained from the statistical model. 相似文献
182.
Hamed Hasanzadeh Kermani Masoud Mokhtary Asghar Alizadeh Dakhel 《International Journal of Polymer Analysis and Characterization》2020,25(7):479-498
Abstract A hybrid nanocomposite based on ethylene propylene diene monomer/carboxylated styrene-butadiene rubber (EPDM/XSBR) blend with different concentrations (0–7 phr) of multiwall carbon nanotube (MWCNT) was prepared on a two-roll mill. The role of grafted maleic anhydride (EPDM-g-MA) as compatibilizer and the effect of different concentrations of MWCNT on mechanical properties, morphology, rheological and curing characteristics of nanocomposites were investigated. The curing behavior of the prepared nanocomposites was studied using a rheometer. Also, the microstructure of nanocomposites was observed using TEM. By increasing the MWCNT concentration in the compatible blends, the curing time and scorch time of the blends decreased, while the maximum and minimum torque increased. Failure surface morphology studies showed that the existence of EPDM-g-MAH compatibilizer improved the distribution of MWCNT within the polymer matrix and uniform distribution of MWCNT with a small amount of aggregation was obtained. On the other hand, the presence of MWCNT in the matrix led to a sharper surface of the fracture. Also, mechanical properties such as modulus, tensile strength, hardness, fatigue, resilience and elongation-at-break for compatible EPDM/XSBR nanocomposite showed better results than those for incompatible composite. 相似文献
183.
Jad Rabah Anam Fatima Hélène Fensterbank Karen Wright Anne Vallée Maïssa Gueye Gotard Burdzinski Gilles Clavier Fabien Miomandre Julie Pham Michel Sliwa Rachel Méallet-Renault Karine Steenkeste Thomas Pino Minh-Huong Ha-Thi Emmanuel Allard 《Helvetica chimica acta》2023,106(6):e202300039
Ferrocene-BODIPY (Fc-BDP) conjugates in which one or two ferrocene entities are linked to the β-positions of the BODIPY core by an ethynyl bridge have been developed. These derivatives were easily and efficiently grafted onto a dual-clickable fullerene platform using CuAAC reactions, leading to a clickable Fc-BDP-C60 triad and a clickable [Fc]2-BDP-C60 tetrad which can be used for further derivatization with complex structures. Due to the extended π-conjugation and the presence of an intramolecular charge transfer band from Fc to BDP, all these conjugates display a broad absorption in the visible region, which is bathochromically shifted when two Fc are appended to the BDP core. Ultrafast multistep electron transfers leading to charge stabilization were demonstrated in the Fc-BDP-C60 triad and [Fc]2-BDP-C60 tetrad by femtosecond transient absorption studies. 相似文献
184.
A new one-pot, efficient three-component condensation of benzaldehydes, 2-naphthol, and carbamates in the presence of silica supported sodium hydrogen sulfate as an effective heterogeneous catalyst for the synthesis of novel 1-carbamato-alkyl-2-naphthol derivatives under solvent-free conditions is described. The present methodology offers several advantages, such as high yields, short reaction times, and very easy workup. 相似文献
185.
A p‐aminophenol modified carbon paste electrode (p‐APMCPE) was constructed for determination of an anticancer drug 6‐thioguanine (6‐TG). The cyclic voltammogram showed that the electrocatalytic oxidation of 6‐TG at the surface of p‐APMCPE occurs at a potential about 840 mV less positive than at an unmodified electrode. Square‐wave voltammetry results presented that the electrocatalytic oxidation peak currents of 6‐TG in pH 9.0 had two linear dynamic ranges in the range of 0.2 to 8.0 and 8.0 to 350.0 μM 6‐TG with a detection limit of 0.08 μM. The kinetic parameters such as electron transfer coefficient (α) and rate constant were determined for the chemical reaction between 6‐TG and p‐aminophenol. Finally, this method was evaluated for the determination of 6‐TG in 6‐thioguanine tablets and urine samples. 相似文献
186.
Kinetic and equilibrium results are compared for the reactions in dimethyl sulfoxide of 1,3,5-trinitrobenzene, 1, and 4-nitrobenzofuroxan, 4, with a series of substituted anilines in the presence of Dabco or in, some cases, quinuclidine. pKa values for the corresponding anilinium ions are reported. The reactions of 1and 4 are likely to proceed through nucleophilic attack by the aniline to yield zwitterionic intermediates which may transfer an acidic proton to the bases present to yield the anionic adducts 9 or 12 respectively. In the formation of 9 from 1 the proton transfer step is rate-limiting; however, the slower interconversion of 4 and its zwitterion leads to only partial rate-limiting proton transfer in the formation of 12. Results with substituted anilines including 2-substituted and N-methyl aniline indicate that steric effects are not a major factor in determining rates of proton-transfer in these systems. Contrary to previous reports no evidence was found for a strong interaction between 1 and Dabco in DMSO. 相似文献
187.
H.-G. Clerc K.-H. Schmidt H. Wohlfarth W. Lang H. Schrader K.E. Pferdekämper R. Jungmann M. Asghar J.P. Bocquet G. Siegert 《Nuclear Physics A》1975,247(1):74-90
The nuclear charge distribution of fission products with mass numbers A = 90, 91, 94, 99, 100, 101 and 104 provided by the mass separator “Lohengrin” was measured. Adjacent elements in the group of the light fission products could be separated by their different energy loss in a carbon absorber. The Z-yields were found to be strongly dependent on the kinetic energy of the fission products. The widths of the nuclear charge distributions are very small, in general, and strongly dependent on A as well as on the kinetic energy. The influence of the neutron evaporation and odd-even effects are clearly detected. An asymmetric nuclear charge distribution was found for A = 104 indicating the suppression of fission fragments with Z = 43. The average nuclear charges of the fission products at their average kinetic energy are in good agreement with the results from measurements of the number of β-decays and K X-ray measurements. The average nuclear charge of the isobar A = 132 was measured at its average kinetic energy with a calibrated secondary electron detector to be Z = 51.14 ± 0.15 which is in very good agreement with the radiochemical results. Thus previous physical measurements indicating a large independent yield for the doubly magic nucleus 132Sn could not be confirmed. 相似文献
188.
Muhammad Yousaf Yaqoob Mohammad Asghar Muhammad Ali Samar Waseem Amir 《Journal of Analytical Chemistry》2022,77(3):318-327
Journal of Analytical Chemistry - A simple and sensitive flow injection chemiluminescence method was developed for the determination of cefixime trihydrate (CFX) based on its enhancing effect on... 相似文献
189.
Dr. Yevheniia Smortsova Dr. Clément Falaise Anam Fatima Dr. Minh-Huong Ha-Thi Prof. Rachel Méallet-Renault Dr. Karine Steenkeste Dr. Serge Al-Bacha Dr. Tesnim Chaib Dr. Loïc Assaud Dr. Marc Lepeltier Dr. Mohamed Haouas Dr. Nathalie Leclerc Dr. Thomas Pino Prof. Emmanuel Cadot 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(68):17094-17103
Polyoxothiometalate ions (ThioPOM) are active hydrogen-evolution reaction (HER) catalysts based on modular assembly built from electrophilic clusters {MoSx} and vacant polyoxotungstates. Herein, the dumbbell-like anion [{(PW11O39)Mo3S4(H2O)3(OH)}2]8− exhibits very high light-driven HER activity, while the active cores {Mo3S4} do not contain any exposed disulfido ligands, which were suspected to be the origin of the HER activity. Moreover, in the catalyst architecture, the two central {Mo3S4} cores are sandwiched by two {PW11O39}7− subunits that act as oxidant-resistant protecting groups and behave as electron-collecting units. A detailed photophysical study was carried out confirming the reductive quenching mechanism of the photosensitizer [Ir(ppy)2(dtbbpy)]+ by the sacrificial donor triethanolamine (TEOA) and highlighting the very high rate constant of the electron transfer from the reduced photosensitizer to the ThioPOM catalyst. Such results provide new insights into the field of molecular catalytic systems able to promote high HER activity. 相似文献
190.