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11.
The job-shop problem is one of the most difficult NP-hard scheduling problems. A 10×10-problem published in 1963 has been solved only recently by Carlier and Pinson using a branch and bound method. Other branch and bound algorithms have been developed recently. The efficiency of all these branch and bound methods relies on the concept of immediate selection which allows to introduce order relations on the setI of all operations to be processed on the same machine before branching. We present new algorithms for immediate selection. Among them are
- anO(max {n logn,f})-algorithm for fixing all disjunctions induced by cliques;
- anO(n 2)-algorithm based on concepts which are different from those used by Carlier and Pinson.
12.
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14.
We study the derivation of a Langevin equation from a microscopic basis in order to elucidate the nature of the random force. We arrive at the conclusion that the consistent interpretation of the microscopic Langevin equation in terms of a stochastic differential equation (SDE) is according to I
o rules. In addition, the random force is in general not Gaussian, and it is hence not completely characterized by its second moments. 相似文献
15.
Fluoride ions and, in about 0.005M concentration, tungstate ions form gelatinous precipitates, poorly soluble in water, with calcium ions. The radiometric determinations
of the above ions are based on these reactions. Accurate radiometric determination can be carried out only if the gelatinous
precipitate formed during titration can be properly separated from the solution. It has been found that in the case of fluoride
ions the application of crystalline, easily filtrable Ca(COO)2·H2O or CaCO3, and in the case of tungstate ions the application of CaWO4 precipitate improves the filtration properties of45CaF2 and45CaWO4, respectively, formed during titration, whereby the radiometric determinations of the above ions become possible. Titrations
were carried out with 0.05M and 0.005M CaCl2 solutions, labelled with45Ca. 相似文献
16.
The structural prerequisites for an elimination of :C(OCH2)2 from the molecular ions of ethylene ketals of cyclic ketones are discussed. 相似文献
17.
Air samples collected at the second Bosporus bridge of Istanbul which carries a heavy traffic load between Asia and Europe,
were analyzed for 22 elements by the INAA method. Pb, Cd and Fe concentrations in the samples were determined by AAS. Iron
concentrations were used as a cross check between the two methods. In order to define the enrichment factors for the elements
in the bridge area, a sample collected from our university campus which can be considered as a rural site, was also analyzed.
Differences were observed especially for Br, Al, Mg, Ti, Cu and Na between the two sites. Based on the results of the samples
from the bridge, we got a value of 0.58(16) for the Br/Pb-ratio. 相似文献
18.
Summary Convex programming techniques were used by Witting and Krafft in [4] in order to reduce a testing problem for composite hypotheses to one for simple hypotheses. This is realized in terms of least favourable pairs of distributions, which represent the solution of the dual of a suitable program. Without further assumptions on the hypotheses, however, the results, derived that way (cf. Baumann [1], Österreicher [6] and Kusolitsch and Österreicher [5]), are of less practical impact. This is due to the fact that in this case the least favourable pairs depend on the level of the testing problem. Conditions avoiding this, were given by Huber and Strassen in [3]. These conditions make use of 2-alternating capacities in the sense of Choquet. The present paper offers a rather general principle of constructing the least favourable distribution in the case, when one of the two hypotheses is simple. This method works also for the local variation model and the Prohorov neighbourhood model in the case of monotone likelyhood ratio. For simple cases—subsuming the gross error model and the total variation model, for which the solution was given by Huber in [2]—a least favourable pair is obtained by using the mentioned technique of construction two times successively. 相似文献
19.
Cabergoline (CAB) is an ergot alkaloid derivative with dopamine agonist activity. A novel, simple, and rapid stability-indicating high-performance liquid chromatographic (HPLC) method for assay of CAB in tablets has been developed and validated. Chromatography was performed on a 4.6 mm i.d. × 250 mm, 5 μm particle, cyano column with acetonitrile–10 mM phosphoric acid, 35:65 (v/v), containing 0.04% triethylamine, as mobile phase, at a flow rate of 1.0 mL min?1, and UV detection at 280 nm. Response was a linear function of concentration in the range 0.1–4 μg mL?1 (r 2 = 0.9999). The recovery of the method was good (99.45%) and RSD values for intra-day and inter-day precision were 0.24–0.88% and 0.66–1.19%, respectively. The method can be used for quality-control assay of CAB in tablets, for stability studies, and for in vitro dissolution studies. 相似文献
20.
The NMR enhancement factor of a frozenCuMn spin glass has been measured at a temperatureT?T g /5. The measurements were performed as function of static magnetic fields of different directions. A two component model of a spin glass has been outlined. One component being a “system of single spins” and the other one being a “subsystem of clusters”. Both components were attributed to different kinds of interaction being RKKY and dipole interaction respectively. The effective anisotropy field of the single spin system consists of two unidirectional contributionsH a s andH a c , which have been measured for different conditions. A second anisotropy fieldH d binds the cluster system to the system of single spins. All anisotropy fields depend on the annealing temperature of the alloys. 相似文献