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51.
No carry over of unmetabolised deoxynivalenol in milk of dairy cows fed high concentrate proportions
Keese C Meyer U Valenta H Schollenberger M Starke A Weber IA Rehage J Breves G Dänicke S 《Molecular nutrition & food research》2008,52(12):1514-1529
To examine the carry over of deoxynivalenol (DON) and its metabolite de-epoxy DON (DOM-1) in milk, lactating German Holstein cows (n = 13) were fed an isoenergetic total mixed ration in Period 1 with 50% concentrates and 5.3 mg DON/kg dry matter (DM) over 11 wk and were compared with control cows (n = 14). In Period 2 (18 wk), an elevated concentrate proportion was compared to a low concentrate ration by dividing the cows into four Groups (n = 8): Control-30 (30% concentrates), Myco-30 (30% concentrates, 4.4 mg DON/kg DM), Control-60 (60% concentrates) and Myco-60 (60% concentrates, 4.6 mg DON/kg DM). Taken both periods together, no unmetabolised DON was detected in milk samples using the HPLC-UV method. DOM-1 concentrations ranged between below the LOD and 3.2 microg/kg milk in mycotoxin fed cows, while control cows did not excrete any measurable amounts of DOM-1. Regarding the concentrate effects, the carry over of DON as DOM-1 in milk was negligible (between 0.0001 and 0.0011) but significantly higher in Group Myco-30 than in Group Myco-60. This effect may result from an altered bioavailability of DON from maize silage which made up a higher proportion of the daily ration. 相似文献
52.
Romulo Silva de Oliveira Andreu Carminati Renan Augusto Starke 《Journal of Parallel and Distributed Computing》2014
Schedulability analysis of real-time multiprocessor systems is usually based on sufficient but not necessary tests that produce pessimistic results. One difficulty in evaluating the effectiveness of sufficient schedulability tests has been distinguishing the cause of a task set failing the test, i.e., finding out whether the task set is in fact not schedulable or it is actually schedulable but the test itself is too pessimistic. Necessary schedulability tests help to distinguish between these two situations, since if a task set fails in the test then it is guaranteed to be unschedulable. An adversary simulator is a scheduling simulator that uses the non-determinism of the task model to generate scenarios that will stress a specific scheduling algorithm, improving the odds of a deadline miss. In this paper we describe a new adversary simulator algorithm for sporadic task sets executed on multiprocessors scheduled by Global Earliest Deadline First (G-EDF). It is shown that this new adversary simulator is more effective as a necessary test than existing approaches. We also estimate the uncertainty regarding G-EDF by applying to the same task sets a well-known sufficient schedulability test from the literature and the necessary schedulability test based on the adversary simulator. 相似文献
53.
D. Kuhlmann-Wilsdorf J. T. Moore E. A. Starke Jr. S. S. Kulkarni 《Metallurgical and Materials Transactions A》1999,30(9):2491-2501
The present state of knowledge regarding “regular” deformation bands (DBs) is reviewed in the light of some recent observations
on DBs in compressed polycrystalline aluminum. These are slablike volume elements within which different selections of slip
systems operate, always fewer than required for homologous deformation, in opposition to the assumption that grains deform
as units which are common to all, the Sachs, the Boas and Schmid, and the Taylor/Bishop and Hill models. The need for a better
integration of this knowledge with not only the origin of deformation textures but also more generally with the theory of
plastic deformation is pointed out. 相似文献
54.
Peter Starke 《Bautechnik》2004,81(6):437-444
Forty years water‐tower at Flensburg‐Mürwick. In the following article is shown the development of an uncommon building. Beginning from competition, design and statics until execution with interior work, the then made notes and photos serve as material for the publication at the four‐decade‐anniversary of the water‐tower. It is described the construction relying on aesthetic interests, as they arised during the cooperation with a notable architect. The widely cantilevering, axially‐symmetric form of the outline and of the watertank were reason, to apply the technology of prestressed concrete, as it was used only a bare decade in the building of bridges. There are statements about the division into prefabricated and in‐situ‐concrete, about the load‐transmission from the tank to the foundation, about work‐preparing and erection of the building. 相似文献
55.
Substructure strengthening has been utilized by the wire industry to produce high strength, high conductivity, ductile aluminum
wire suitable for electrical usage. This paper describes the choice of alloy additions and production methods necessary for
producing and stabilizing a small subgrain structure. The interrelation between the various manufacturing steps, such as casting,
rolling, and drawing, and the resulting microstructure which controls the electrical and mechanical properties is discussed.
The necessity for strict control of the processing parameters established for various aluminum wire products is emphasized.
This paper is based on a presentation made at a symposium on “Mechanical-Thermal Processing and Dislocation Substructure Strengthening”,
held at the Annual Meeting in Las Vegas, Nevada, on February 23, 1976 under the sponsorship of the TMS/IMD Heat Treating Committee. 相似文献
56.
Fuel cells are considered to be one of the most promising sources of distributed energy because of their high efficiency, low environmental impact and scalability. Unfortunately, multiple complications exist in fuel cell operation. Fuel cells cannot accept current in the reverse direction, do not perform well with ripple current, have a low output voltage that varies with age and current, respond sluggishly to step changes in load and are limited in overload capabilities. For these reasons, power converters are often necessary to boost and regulate the voltage as a means to provide a stiff applicable DC power source. Furthermore, the addition of an inverter allows for the conversion of DC power to AC for an utility interface or for the application of an AC motor. To help motivate the use of power conditioning for the fuel cell, a brief introduction of the different types, applications and typical electrical characteristics of fuel cells is presented. This is followed by an examination of the various topologies of DC-DC boost converters and inverters used for power conditioning of fuel cells. Several architectures to aggregate multiple fuel cells for high-voltage/high-power applications are also reviewed. 相似文献
57.
The authors discuss aliasing errors in signature analysis registers for self-testing networks and review analytical results. The results show that when p, the probability that an error will occur at a network output, is close to 1/2, there is a bound of the aliasing error. The analysis uses a graph to represent the probability of transition, the Markov process, and z-transforms to analyze the behavior of the signature analysis register. For very small p(p?0) and very large p(p?1), the aliasing error solution for primitive polynomials is a series of terms (1-?)n in magnitude (where n is the number of random patterns being applied to the network or the length of the network output sequence). As compared with nonprimitive polynomials, whose solution is n(1-?)n or n2(1-?)n, in general primitive polynomials are much better with respect to aliasing. Simulation results are shown for aliasing errors for these polynomials, which give insight as to how aliasing occurs. 相似文献
58.
The effect of copper content and heat treatment on the stress corrosion characteristics of Ai-6Zn-2Mg-X Cu alloys 总被引:1,自引:0,他引:1
The effect of copper and aging on the stress corrosion characteristics of Al-6 pct Zn-2 pct Mg-(0.01-2.1) pct Cu alloys in
3.5 pct NaCl was studied with other variables remaining constant. In the peak-strength condition the crack velocity in the
stress-independent region decreased by two orders of magnitude when copper was increased from 0.01 to 2.1 pct. In the stress-dependent
region crack velocity decreased only for copper contents higher than 1 pct. Overaging further reduced the plateau crack velocity
in all the alloys studied. The results are interpreted on the basis of the effects of copper and aging on the deformation
mechanism and electrochemical activity of the phases. 相似文献
59.
The effect of microstructure and deformation behavior on the hot ductility of Ti-6Al-2Nb-1Ta-0.8Mo 总被引:1,自引:0,他引:1
Hot ductility of the alloy Ti-6Al-2Nb-lTa-0.8Mo has been correlated with microstructure and fracture behavior. Low hot ductility was found to be associated with strain localization within the grain boundary alpha phase, producing void formation along the prior-beta grain boundaries and inter-granular fracture. Microstructural features that appear to be critical to the strain localization process are beta grain shape and alpha phase morphology. For the case of Widmanstätten + grain boundary alpha phase morphologies, equiaxed prior-beta grains formed by annealing above the beta transus are required to produce significant strain localization. For the beta processed structure with elongated beta grains due to working above the beta transus temperature, the orientation of the grain boundary alpha phase limits strain localization due to low resolved shear stress. The martensitic Widmanst?ten alpha prime structure formed by quenching from above the beta transus temperature rapidly forms grain boundary alpha upon reheating to temperatures high in the alpha + beta phase field. This results in strain localization in the grain boundary regions in an apparently similar manner to that observed in the Widmanstätten + grain boundary alpha phase morphologies with equiaxed prior-beta grains. 相似文献
60.
F. S. Lin E. A. Starke S. B. Chakrabortty A. Gysler 《Metallurgical and Materials Transactions A》1984,15(6):1229-1246
An alpha + beta Ti-6Al-2Nb-lTa-0.8Mo alloy with an initial Widmanstätten structure was thermally treated to produce a wide range of microstructures. The effects of individual microstructural parameters on deformation behavior and mechanical properties were investigated. The results show that the Widmanstätten colony boundaries are major barriers to slip. However, the slip distance can be decreased to a distance equal to the thickness of acicular alpha by transforming the beta phase in the Widmanstätten structure to martensite by quenching from 950°C. The decrease in slip distance is accompanied by a 25 pct increase in yield strength with no loss in ductility. A large decrease in ductility occurs after excursions above the beta-transus. The development of both equiaxed beta grains during heating in the beta phase field and continuous grain boundary alpha during cooling in the alpha + beta phase field leads to strain localization along prior beta grain boundaries. 相似文献