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61.
Let , be mixing one-sided subshifts of finite type such that . We show a necessary and sufficient condition for the existence of mixing Markov shifts , , , and a conjugacy with , such that the sets of letters appearing in both systems are the same, more precisely, .

  相似文献   

62.
Reacting VO(acac)2 with six equivalents of dibenzylphosphinic acid in the presence of 4,4′-bipyridine or μ2-N1,N2-di(pyridin-4-yl)oxalamide leads to trimeric (V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6(4,4′-bipyridine) or the hexamer [(V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6]2(μ2-N1,N2-di(pyridin-4-yl)oxalamide). The complexes were characterized by spectroscopic (FTIR and 1H NMR spectroscopies), TGA, and by single crystal X-ray diffraction measurements. The structures consist of a planar central core where three vanadium ions are arranged in the form of a quasi-isosceles triangle and contain an interstitial O which is multiply bonded to one V and weakly interacting at different bond distances to the remaining two V ions.  相似文献   
63.
64.
Model investigations, carried out as laboratory coalification reactions with humous and sapropelitic sediments of different maturation degree, showed that conclusions can be drawn about the character of the parent rock of a natural gas using data of the chemical and isotopic composition of the organic substance in sediments and its coalification products.

Several examples demonstrate, that the following parameters have proved as suitable fades- and in part as maturity criteria: CH4/Σ HKW; C2H6/CH4, i-/n-C4H10, 13C-abundance of organic substance, 13C-abundance of methane.

For a complex interpretation all results obtained from coalification experiments over some years were stored in a data file. By means of cluster analysis all samples were classified in groups corresponding to their characteristics represented by the above mentioned five criteria. Four clusters resulted depending on maceral composition of the tested organic sediments. The differentiating criteria of these clusters are discussed.  相似文献   
65.
We investigate the structure and electronic properties of phosphatidylcholine (PC) under different degrees of hydration at the single-molecule and monolayer type level by linear scaling ab initio calculations. Upon hydration, the phospholipid undergoes drastic long-range conformational rearrangements which lead to a sickle-like ground-state shape. The structural unit of the tilted gel-phase PC appears to be a water-bridged PC dimer. We find that hydration dramatically alters the surface potential, dipole and quadrupole moments of the lipids and consequently guides the interactions of the lipids with other molecules and the communication between cells.  相似文献   
66.
We study nonequilibrium steady states of lattice gases with nearest-neighbor interactions that are driven between two reservoirs. Density profiles in these systems exhibit oscillations close to the reservoirs. We demonstrate that an approach based on time-dependent density functional theory copes with these oscillations and predicts phase diagrams of bulk densities to a good approximation under arbitrary boundary-reservoir couplings. The minimum or maximum current principles can be applied only for specific bulk-adapted couplings. We show that they generally fail to give the correct topology of phase diagrams but can still be useful for getting insight into the mutual arrangement of different phases.  相似文献   
67.
The burning of fossil fuels has released a large quantity of pollutants into the atmosphere. In this context, sulfur dioxide is one of the most noxious gas which, on reacting with moist air, is transformed into sulfuric acid, causing the acid rain. In response, many countries have reformulated their legislation in order to enforce the commercialization of fuels with very low sulfur levels. The existing desulfurization processes cannot remove such low levels of sulfur and thus a biodesulfurization has been developed, where the degradation of sulfur occurs through the action of microorganisms. Rhodococcus erythropolis has been identified as one of the most promising bacteria for use in the biodesulfurization. In this study, the effectiveness of the strain R. erythropolis ATCC 4277 in the desulfurization of dibenzothiophene (DBT) was evaluated in a batch reactor using an organic phase (n-dodecane or diesel) concentrations of 20, 80, and 100 % (v/v). This strain was able to degrade 93.3, 98.0, and 95.5 % of the DBT in the presence of 20, 80, and 100 % (v/v) of dodecane, respectively. The highest value for the specific DBT degradation rate was 44?mmol DBT?·?kg DCW?1?·?h?1, attained in the reactor containing 80 % (v/v) of n-dodecane as the organic phase.  相似文献   
68.
This contribution proposes a fully three dimensional “continuum damage model” (CDM) to describe the interlaminar and intralaminar failure mechanisms of transversely isotropic elastic-brittle materials under static loading. The constitutive model is derived from an energy function with independent damage variables for each damage mode. The evolution law is based on energy dissipation within the damage process, taking into account the critical energy release rate to weaken the effect of mesh dependent outcome. The onset of damage can be predicted with Cuntze's failure mode concept [1] as well as with Hashin's failure criteria. In this model linear stress decreasing is assumed. In addition, an implicit-explicit integration scheme, first proposed by Oliver [3] for isotropic damage models, is adapted to increase the stability and robustness of numerical simulations and to decrease the computational cost of material failure analyses. By comparing the results from implicit-explicit integration schemes and standard implicit integration schemes, a high level of agreement is found. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   
69.
The uncertainty principle is a fundamental concept in quantum mechanics, harmonic analysis and signal and information theory. It is rooted in the framework of quantum mechanics, where it is known as the Heisenberg uncertainty principle. In general, the uncertainty principle gives a lower bound on the product of variances for any state f with respect to two self-adjoint operators:
vf(A)vf(B) 3 \frac14|ef([A,B])|2.v_f(A)v_f(B)\ge\frac{1}{4}|e_f([A,B])|^2.  相似文献   
70.
Probe measurements were carried out in the positive column of an argon glow discharge in a flow system with different admixtures of hexamethyldisiloxane (HMDS). From this the mean electron energy ne, number density ne and gradient E were determined. Some results concerning the predominant ionization mechanism and the ion distribution in the gas phase could be obtained. By means of probes it is also possible to get some information about the deposition mechanism in polymerizing plasmas.  相似文献   
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