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51.
52.
Hilde Lea Lein Øystein Skottun Andersen Per Erik Vullum Edgar Lara-Curzio Randi Holmestad Mari-Ann Einarsrud Tor Grande 《Journal of Solid State Electrochemistry》2006,10(8):635-642
Young’s modulus, strain–stress behavior, fracture strength, and fracture toughness of (0≤×≤1) materials have been investigated in the temperature range 20–1,000°C. Young’s moduli of and , measured by resonant ultrasound spectroscopy, were 130±1 and 133±3 GPa, respectively. The nonlinear stress–strain relationship
observed by four-point bending at room temperature was inferred as a signature of ferroelastic behavior of the materials.
Above the ferroelastic to paraelastic transition temperature, the materials showed elastic behavior, but due to high-temperature
creep, a nonelastic respond reappeared above ∼800°C. The room temperature fracture strength measured by four-point bending
was in the range 107–128 MPa. The corresponding fracture toughness of , measured by single edge V-notch beam method, was 1.16±0.12 MPa·m1/2. The measured fracture strength and fracture toughness were observed to increase with increasing temperature. The fracture
mode changed from intragranular at low temperature to intergranular at high temperature. Tensile stress gradient at the surface
of the materials caused by a frozen-in gradient in the oxygen content during cooling was proposed to explain the low ambient
temperature fracture strength and toughness. 相似文献
53.
In this paper, we investigate the permutation behavior of a class of quadrinomials. Each term of these quadrinomials has a Niho-type exponent, and two sets of coefficient triples making the quadrinomials to be permutations are obtained. We use a substitution to transform the permutation problem into the root distribution problem in the unit circle of certain quadratic and cubic equations. 相似文献
54.
Tor A. Kwembe 《Nonlinear Analysis: Theory, Methods & Applications》2010,73(10):3162-3170
In this paper we consider a semilinear equation with a generalized Wentzell boundary condition. We prove the local well-posedness of the problem and derive the conditions of the global existence of the solution and the conditions for finite time blow-up. We also derive an estimate for the blow-up time. 相似文献
55.
Daniel Pinchuk Yosi Kratish Jomon Mathew Lieby Zborovsky Dmitry Bravo‐Zhivotovskii Boris Tumanskii Yitzhak Apeloig 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(22):7513-7517
The first two persistent silenyl radicals (R2C=Si.?R), with a half‐life (t1/2) of about 30 min, were generated and characterized by electron paramagnetic resonance (EPR) spectroscopy. The large hyperfine coupling constants (hfccs) (a(29Siα)=137.5–148.0 G) indicate that the unpaired electron has substantial s character. DFT calculations, which are in good agreement with the experimentally observed hfccs, predict a strongly bent structure (?C=Si?R=134.7–140.7°). In contrast, the analogous vinyl radical, R2C=C.?R (t1/2≈3 h), exhibits a small hfcc (a(13Cα)=26.6 G) and has a nearly linear geometry (?C=C?R=168.7°). 相似文献
56.
Lieby Zborovsky Arseni Kostenko Dmitry Bravo‐Zhivotovskii Yitzhak Apeloig 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(41):14666-14670
The E and Z geometric isomers of a stable silene (tBu2MeSi)(tBuMe2Si)Si=CH(1‐Ad) ( 1 ) were synthesized and characterized spectroscopically. The thermal Z to E isomerization of 1 was studied both experimentally and computationally using DFT methods. The measured activation parameters for the 1Z ? 1E isomerization are: Ea=24.4 kcal mol?1, ΔH≠=23.7 kcal mol?1, ΔS≠=?13.2 e.u. Based on comparison of the experimental and DFT calculated (at BP86‐D3BJ/def2‐TZVP(‐f)//BP86‐D3BJ/def2‐TZVP(‐f)) activation parameters, the Z?E isomerization of 1 proceeds through an unusual (unprecedented for alkenes) migration–rotation–migration mechanism (via a silylene intermediate), rather than through the classic rotation mechanism common for alkenes. 相似文献
57.
Paul T. Ludford III Shenghua Yang Marcela S. Bucardo Prof. Yitzhak Tor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(13):e202104472
A new fluorescent ribonucleoside alphabet (mthN) consisting of pyrimidine and purine analogues, all derived from methylthieno[3,4-d]pyrimidine as the heterocyclic core, is described. Large bathochromic shifts and high microenvironmental susceptibility of their emission relative to previous alphabets derived from thieno[3,4-d]pyrimidine (thN) and isothiazole[4,3-d]pyrimidine (tzN) scaffolds are observed. Subjecting the purine analogues to adenosine deaminase, guanine deaminase and T7 RNA polymerase indicate that, while varying, all but one enzyme tolerate the corresponding mthN/mthNTP substrates. The robust emission quantum yields, high photophysical responsiveness and enzymatic accommodation suggest that the mthN alphabet is a biophysically viable tool and can be used to probe the tolerance of nucleoside/tide-processing enzymes to structural perturbations of their substrates. 相似文献
58.
We show that the support of minimum Lee weight codewords having Hamming weight 5 in the Preparata code over Z4 form a 3-(2m,5,10) design for any odd integer m 3. 相似文献
59.
In this paper we show that the support of the codewords of each type in the Kerdock code of length 2m over Z4 form 3-designs for any odd integer
. In particular, twonew infinite families of 3-designs are obtained in this constructionfor any odd integer
. In particular, twonew infinite families of 3-designs are obtained in this constructionfor any odd integer
, whose parameters are
,and
. 相似文献
60.