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31.
32.
Selby TM Meloni G Goulay F Leone SR Fahr A Taatjes CA Osborn DL 《The journal of physical chemistry. A》2008,112(39):9366-9373
Product channels for the self-reaction of the resonance-stabilized allyl radical, C3H5 + C3H5, have been studied with isomeric specificity at temperatures from 300-600 K and pressures from 1-6 Torr using time-resolved multiplexed photoionization mass spectrometry. Under these conditions 1,5-hexadiene was the only C6H10 product isomer detected. The lack of isomerization of the C6H10 product is in marked contrast to the C6H6 product in the related C3H3 + C3H3 reaction, and is due to the more saturated electronic structure of the C6H10 system. The disproportionation product channel, yielding allene + propene, was also detected, with an upper limit on the branching fraction relative to recombination of 0.03. Analysis of the allyl radical decay at 298 K yielded a total rate coefficient of (2.7 +/- 0.8) x 10(-11) cm(3) molecule(-1) s(-1), in good agreement with previous experimental measurements using ultraviolet kinetic absorption spectroscopy and a recent theoretical determination using variable reaction coordinate transition state theory. This result provides independent indirect support for the literature value of the allyl radical ultraviolet absorption cross-section near 223 nm. 相似文献
33.
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35.
We investigate the connection between interference and computational power within the operationally defined framework of generalised probabilistic theories. To compare the computational abilities of different theories within this framework we show that any theory satisfying four natural physical principles possess a well-defined oracle model. Indeed, we prove a subroutine theorem for oracles in such theories which is a necessary condition for the oracle model to be well-defined. The four principles are: causality (roughly, no signalling from the future), purification (each mixed state arises as the marginal of a pure state of a larger system), strong symmetry (existence of a rich set of nontrivial reversible transformations), and informationally consistent composition (roughly: the information capacity of a composite system is the sum of the capacities of its constituent subsystems). Sorkin has defined a hierarchy of conceivable interference behaviours, where the order in the hierarchy corresponds to the number of paths that have an irreducible interaction in a multi-slit experiment. Given our oracle model, we show that if a classical computer requires at least n queries to solve a learning problem, because fewer queries provide no information about the solution, then the corresponding “no-information” lower bound in theories lying at the kth level of Sorkin’s hierarchy is \(\lceil {n/k}\rceil \). This lower bound leaves open the possibility that quantum oracles are less powerful than general probabilistic oracles, although it is not known whether the lower bound is achievable in general. Hence searches for higher-order interference are not only foundationally motivated, but constitute a search for a computational resource that might have power beyond that offered by quantum computation. 相似文献
36.
The eigen frequencies of radial pulsations of neutron stars are calculated in a strong magnetic field. At low densities we
use the magnetic BPS equation of state (EOS) similar to that obtained by Lai and Shapiro while at high densities the EOS obtained
from the relativistic nuclear mean field theory is taken and extended to include strong magnetic field. It is found that magnetized
neutron stars support higher maximum mass whereas the effect of magnetic field on radial stability for observed neutron star
masses is minimal. 相似文献
37.
Denote byX
q
the reduced space ofSU
2 monopoles of chargeq in 3. In this paper the cohomology ofX
q
, the cohomology with compact supports ofX
q
, and the image of the latter in the former are all calculated as representations of /q which acts onX
2. This provides a non-trivial lower bound for theL
2 cohomology ofX
q
which is compatible with some conjectures of Sen. It is also shown that, granted some assumptions about the metric onX
q
, itsL
2 cohomology does not exceed this bound in the situation referred to in the paper as the coprime case.The work described here was carried out partly at the University of Texas at Austin. 相似文献
38.
Several heterocyclic acetic acids and esters were synthesized by allowing the appropriate thiourea, ethylenethiourea or trimethylenethiourea to react with 4-chloroacetoacetic esters, followed by acid hydrolysis to the hydrochlorides of the free acids. Both esters and acids of 2-aminothiazole-4-acetic acid, 5,6-dihydro-imidazo[2,1-b]thiazole-3-acetic acid and 6,7-dihydro-5H-thiazolo[3,2-c]pyrimidine-3-acetic acid were obtained. 相似文献
39.
Andrew F. Dyke Selby A.R. Knox Pamela J. Naish 《Journal of organometallic chemistry》1980,199(2):C47-C49
Treatment of [Ru2(CO)(μ-CO) {μ-C(O)C2Ph2} (η-C 5H5)2] with allene in toluene at 100°C displaces diphenylacetylene and produces [Ru(CO)(η-C5H5)-{η3-C3H4Ru(CO)2(η-C5H5)}]; upon protonation a 1-methylvinyl cation [Ru2(CO)2(μ-CO){μ-C(Me)CH2}(η-C5H5)2]+ is formed which undergoes nucleophillic attack by hydride to yield the μ-dimethylcarbene complex [Ru2(CO)2-(μ-CO)(μ-CMe2)(η-C5H5)2]. 相似文献
40.
Condensation of ethyl 4-chloroacetoacetate with 4-amino-6-hydroxy-2-pyrimidinethiol produced ethyl 3-hydroxy-5-amino-7-oxothiazolino[3,2-a]pyrimidin-3-acetate ( 7a ) on crystallization. Subsequent ring closure of 7a produced the tricyclic 6a-hydroxy-5,6,6a,7-tetrahydro-8-thia-1,4-diazacycl[3.3.2]azin-2,5-dione ( 8 ). The structure of 8 was confirmed by crystal x-ray diffraction analysis. 相似文献