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81.
82.
M. S. Sidhu K. B. Kohli P. V. K. Bhatia S. S. Sandhu 《Journal of Radioanalytical and Nuclear Chemistry》1994,187(5):375-383
Uranyl ion is photochemically reduced to uranium(IV) in the presence of triethylamine and triethylamine is oxidized to secondary amine and acetaldehyde. On the basis of product analysis, temperature independent quantum yields for uranium(IV) formation and abnormal Stern-Volmer plots rule out the simple collisional photochemical annihilation of excited uranyl ion with triethylamine. Static annihilation has a significant contribution in addition to dynamic annihilation. 相似文献
83.
J. Adam K. Katovsky M. Majerle M. I. Krivopustov V. Kumar Chitra Bhatia Manish Sharma A. A. Solnyshkin V. M. Tsoupko-Sitnikov 《The European Physical Journal A - Hadrons and Nuclei》2010,43(2):159-173
The spallation lead target in the “Energy plus Transmutation” set-up, covered with uranium blanket, was irradiated by the
1.6GeV deuteron beam from the Nuclotron accelerator at the Joint Institute for Nuclear Research in Dubna. The neutrons generated
in the subcritical uranium blanket are used to activate the radioactive uranium and thorium samples outside the blanket. Rates
of the (n,g \gamma) , (n, f) and (n, 2n) reactions are determined for some residual nuclei. The ratio of the reaction rates R(n, 2n)/R(n, f) is estimated to be 27(9)%. Contributions of the neutrons with energy E
n > 20 MeV to the (n, f) reaction rate is ∼ 57% for 232Th and ∼ 37% for natU , respectively. To compare with the experimental results, the reaction rates are simulated by generating the neutron fluxes
employing two different models, the beam shapes by the MCNPX 2.6.c code and making use of the appropriate libraries of cross-sections.
The transmutation power of the set-up is estimated using the average (n,g \gamma) and (n, 2n) reaction rates and compared with some of the results of the TARC experiment. 相似文献
84.
We investigate the interaction of ethylene and ethane with a Cu-tricarboxylate complex and show that at low loadings the lighter molecule has a higher binding energy as a result of an increased interaction with the framework Cu and stronger hydrogen bonding with the basic framework oxygens. This leads to selective adsorption of ethylene by a factor of about 2 at low pressure, which is overcome by the stronger van der Waals interaction of ethane at high loadings, explaining recent literature data. The results suggest the possibility of separation of light hydrocarbons at low pressures or in trace amounts. 相似文献
85.
Multiwall carbon nanotubes (MWNTs) filled with Fe nanoparticles (NPs) have been synthesized by thermal chemical vapor deposition of ferrocene alone as the precursor. The MWNTs were grown at different temperatures: 980 and 800 °C. Characterization of as-prepared MWNTs was done by scanning and transmission electron microscopy, and X-ray diffraction. The transmission electron microscopy study revealed that Fe NPs encapsulated in MWNTs grown at 980 and 800 °C are spherical and rod shaped, respectively. Room-temperature vibrating sample magnetometer studies were done on the two samples up to a field of 1 T. The magnetization versus magnetic field loop reveals that the saturation magnetization for the two samples varies considerably, almost by a factor of 4.6. This indicates that Fe is present in different amounts in the MWNTs grown at the two different temperatures. 相似文献
86.
Carbons with slitlike pores can serve as effective host materials for storage of hythane fuel, a bridge between the petrol combustion and hydrogen fuel cells. We have used grand canonical Monte Carlo simulation for the modeling of the hydrogen and methane mixture storage at 293 K and pressure of methane and hydrogen mixture up to 2 MPa. We have found that these pores serve as efficient vessels for the storage of hythane fuel near ambient temperatures and low pressures. We find that, for carbons having optimized slitlike pores of size H congruent with 7 A (pore width that can accommodate one adsorbed methane layer), and bulk hydrogen mole fraction >or=0.9, the volumetric stored energy exceeds the 2010 target of 5.4 MJ dm(-3) established by the U.S. FreedomCAR Partnership. At the same condition, the content of hydrogen in slitlike carbon pores is approximately = 7% by energy. Thus, we have obtained the composition corresponding to hythane fuel in carbon nanospaces with greatly enhanced volumetric energy in comparison to the traditional compression method. We proposed the simple system with added extra container filled with pure free/adsorbed methane for adjusting the composition of the desorbed mixture as needed during delivery. Our simulation results indicate that light slit pore carbon nanomaterials with optimized parameters are suitable filling vessels for storage of hythane fuel. The proposed simple system consisting of main vessel with physisorbed hythane fuel, and an extra container filled with pure free/adsorbed methane will be particularly suitable for combustion of hythane fuel in buses and passenger cars near ambient temperatures and low pressures. 相似文献
87.
Uranium trace characterization of crystalline GeS, sputtered thin films of GeS and amorphous SiH on quartz substrates, and crystalline p-type Si using the technique of solid state nuclear track detectors is reported. Concentration and distribution of uranium in these materials studied are presented. Using uranium as microprobe, it is observed that uranium prefers to be in the cleavage planes of GeS crystals. There seems to be a link between uranium concentration and the thermally induced defects in Si. 相似文献
88.
It is shown that every nonsingular square complex matrix Z can be factored as Z=eLeiTeiKeS, where S and T are real symmetric matrices, and K and L are real skew-symmetric matrices. New proofs are given for some related decomposition theorems for unitary and positive definite matrices. 相似文献
89.
In this article, we look beyond convexity and introduce the four new classes of functions, namely, approximate pseudoconvex functions of type I and type II and approximate quasiconvex functions of type I and type II. Suitable examples illustrating the non emptiness of the newly defined classes and distinguishing them from the existing classical notions of pseudoconvexity and quasiconvexity are provided. These newly defined concepts are then employed to establish sufficient optimality conditions for the quasi efficient solutions of a vector optimization problem. 相似文献
90.
Reaction of iron(III) chloride with 1,2-ethanebis(diphenylphosphine oxide) in an ethanol/chloroform mixture formed a 11 adduct of stoichiometry FeCl3(L-L) which has been characterized by X-ray crystallography as [FeCl2(L-L)2] [FeCl4]. The structure was solved by the heavy atom method, using MoK diffractometer data and refined by full-matrix least squares toR=0.044 for 8506 observed reflections. The coordination is slightly distorted octahedral for the cation with acis-arrangement of the chlorine atoms and a seven-membered chelate ring formation by Ph2P(O)CH2CH2P(O)Ph2 with the donor O atoms also in acis arrangement. The Fe-Cl distances are equal at 2.306(1) Å but the Fe-O distances differ significantly in each of the two ligands, (avg. 2.076(2) Å; avg. 1.975(3) Å). 相似文献