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11.
Essam K. Al-Hussaini Nagi S. Abd-El-Hakim 《Annals of the Institute of Statistical Mathematics》1989,41(3):617-622
Motivated by the idea that different causes of failure of a given system could lead to different failure distributions, a mixture of two-component distributions, one of which is the two-parameter Inverse Gaussian (IG) and the other the two-parameter Weibull (W), is proposed as a failure model. The IG-W mixture model convers several types of failure rates (FR's). It is shown that depending on the parameter values, the IG-W mixture model is capable of covering six different combinations of FR's, as one of the components has an upsidedown bathtub failure rate (UBTFR) or increasing failure rate (IFR) and the other component has a decreasing failure rate (DFR), constant failure rate (CFR), or IFR. A study is made for the mixed FR based on these six combinations. 相似文献
12.
The method of neutron activation and gamma-ray spectrometry was used for studying galvanic corrosion of dental amalgam. The
behaviour of galvanic couples of zinc containing and zinc free amalgam with dissimilar electrodes from other restorative material
was investigated in various electrolytic media, in absence and presence of oxygen. Severe corrosion of amalgam takes place
when coupled with gold electrodes. 相似文献
13.
14.
In this paper, we consider the integration of facility placement in an existing layout and the configuration of one or two connecting sub-aisles. This is relevant, for example, when placing a new machine/department on a shop floor with existing machines/departments and an existing aisle structure. Our work is motivated by the work of Savas et al. [Savas, S., Batta, R., Nagi, R., 2002. Finite-size facility placement in the presence of barriers to rectilinear travel. Operations Research 50 (6), 1018–1031], that considered the optimal planar placement of a finite-size facility in the presence of existing facilities. Our work differs from theirs in that we consider material handling to be restricted to the aisle structure. We do not allow the newly placed facility to overlap with existing facilities or with the aisle structure. Facilities are rectangular and travel is limited to new or existing aisles. We show that there are a finite number of candidate placements for the new facility. Algorithms are developed to find the optimal placement and the corresponding configurations for the sub-aisles. Complexity of the solution method is analyzed. Also, a numerical example is provided to explore the impact of the number of sub-aisles added. 相似文献
15.
Gerbaux P Dechamps N Flammang R Nagi Reddy P Srinivas R 《Rapid communications in mass spectrometry : RCM》2006,20(2):151-156
Dissociative ionization of the selenourea Se=C(NH(2))(2) (2) conveniently generates beams of pure isocyanoselenic acid radical cations. The HNCSe(.+) connectivity is established by collisional activation and by associative ion-molecule reactions with dimethyl sulfide or nitric oxide using a large-scale hybrid mass spectrometer. 相似文献
16.
Lunderberg E DeYoung PA Kohley Z Attanayake H Baumann T Bazin D Christian G Divaratne D Grimes SM Haagsma A Finck JE Frank N Luther B Mosby S Nagi T Peaslee GF Schiller A Snyder J Spyrou A Strongman MJ Thoennessen M 《Physical review letters》2012,108(14):142503
Evidence for the ground state of the neutron-unbound nucleus (26)O was observed for the first time in the single proton-knockout reaction from a 82 MeV/u (27)F beam. Neutrons were measured in coincidence with (24)O fragments. (26)O was determined to be unbound by 150(-150)(+50) keV from the observation of low-energy neutrons. This result agrees with recent shell-model calculations based on microscopic two- and three-nucleon forces. 相似文献
17.
E. Rajanarendar M. Nagi Reddy K. Govardhan Reddy S. Rama Krishna 《Tetrahedron letters》2012,53(23):2909-2913
l-Proline acts as an efficient organocatalyst and found to promote one-pot three-component aza-Diels–Alder reaction of aryl or isoxazole imines formed in situ from aromatic or isoxazoleamines and aromatic aldehydes with nitrostyrylisoxazoles to afford the isoxazolyl tetrahydroquinolines or isoxazolo[2,3-a]pyrimidines, respectively, in excellent yields at ambient temperature under neutral conditions. 相似文献
18.
This paper addresses the finite size 1-center placement problem on a rectangular plane in the presence of barriers. Barriers are regions in which both facility location and travel through are prohibited. The feasible region for facility placement is subdivided into cells along the lines of Larson and Sadiq [R.C. Larson, G. Sadiq, Facility locations with the Manhattan metric in the presence of barriers to travel, Operations Research 31 (4) (1983) 652–669]. To overcome complications induced by the center (minimax) objective, we analyze the resultant cells based on the cell corners. We study the problem when the facility orientation is known a priori. We obtain domination results when the facility is fully contained inside 1, 2 and 3-cornered cells. For full containment in a 4-cornered cell, we formulate the problem as a linear program. However, when the facility intersects gridlines, analytical representation of the distance functions becomes challenging. We study the difficulties of this case and formulate our problem as a linear or nonlinear program, depending on whether the feasible region is convex or nonconvex. An analysis of the solution complexity is presented along with an illustrative numerical example. 相似文献
19.
20.
I. H. Qureshi F. I. Nagi M. Nasra M. N. Cheema 《Journal of Radioanalytical and Nuclear Chemistry》1971,7(2):221-226
A rapid procedure has been developed for the mutual separation of antimony and arsenic using tribenzylamine as the extracting
agent. The extraction behaviours of Sb(III), Sb(V), As(III), As(V) and Au(III) have been studied as a function of the acidity
of the aqueous phase. Various factors which affect the extraction of these complexes have been studied and optimized. The
procedure was then applied to lead base alloy for the simultaneous determination of antimony, arsenic and copper. Chemical
recoveries were quantitative and only about one hour is required for the chemical processing of duplicate samples. 相似文献