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51.
Abstract. Part of the remit of public sector management includes planning and reflecting on capital expenditure on new technology. With this in mind, the role that information systems play in supporting improvements in e-government service delivery to stakeholder groups continues to attract much attention. The authors of this paper seek to define the scope and role that information systems evaluation plays within the public sector. In particular, the authors assess whether public sector organizations might benefit from the use of established ex-ante evaluation techniques, when applied to analyse the impact of e-government information systems. Following a comprehensive review of the normative literature, an initial conceptual framework for public sector information systems evaluation is proposed, which is then empirically explored within two local government authorities. The conceptual framework is then revised by using the structured case approach, which is dependent on an iterative research cycle where triangulated data are elicited. This then supports the emergence of new concepts during each research cycle that leads to the view that information systems evaluation in the public sector is a process of experiential and subjective judgement, which is grounded in opinion and world views. This leads the authors to challenge the appropriateness of traditional modes of investment appraisal when applied in the public sector. The finalized framework embraces investment decisions, evaluation methods, culture and structure, as well as post hoc evaluation. It emphasizes the importance of situated, interpretive user assessments in evaluating e-government investments.  相似文献   
52.
The paper discusses the appraisal, in terms of geological risk, of the new Athens–Corinth highway and railway projects in the area of Kakia Skala, which exhibits strong characteristics of neotectonic activity. After detailed mapping of the faults and the evaluation of their future behavior based on geological criteria, a seismic displacement of up to 0.5 m along the fault line was considered possible. Modifications were made to the initial alignment so that the engineering structures, particularly bridges, were located away from the main active fault. In places where such changes were not possible, for technical or economic reasons, the construction of over-bored tunnels was recommended.   相似文献   
53.
The paper estimates the anticipated changes in the seepage conditions towards the karstic aquifer, the recharge of the aquifer from the combined rainfall, seepage and exploitation as well as the potential alteration in the quality of the aquifer due to the creation of a nearby reservoir. It is shown that despite the somewhat increased seepage of polluted river water towards the aquifer, the quality of the groundwater in the karstic aquifer is not expected to degrade appreciably. However, since the water of the aquifer is used for the supply of neighbouring communities, it is proposed that in the areas where the thickness of the intervening semi-permeable alluvia is small, artificial sealing is installed using either compacted clay or plastic membranes.  相似文献   
54.
Alpha-1 antitrypsin deficiency (AATD) is caused by a single mutation in the SERPINA1 gene, which culminates in the accumulation of misfolded alpha-1 antitrypsin (ZAAT) within the endoplasmic reticulum (ER) of hepatocytes. AATD is associated with liver disease resulting from hepatocyte injury due to ZAAT-mediated toxic gain-of-function and ER stress. There is evidence of mitochondrial damage in AATD-mediated liver disease; however, the mechanism by which hepatocyte retention of aggregated ZAAT leads to mitochondrial injury is unknown. Previous studies have shown that ER stress is associated with both high concentrations of fatty acids and mitochondrial dysfunction in hepatocytes. Using a human AAT transgenic mouse model and hepatocyte cell lines, we show abnormal mitochondrial morphology and function, and dysregulated lipid metabolism, which are associated with hepatic expression and accumulation of ZAAT. We also describe a novel mechanism of ZAAT-mediated mitochondrial dysfunction. We provide evidence that misfolded ZAAT translocates to the mitochondria for degradation. Furthermore, inhibition of ZAAT expression restores the mitochondrial function in ZAAT-expressing hepatocytes. Altogether, our results show that ZAAT aggregation in hepatocytes leads to mitochondrial dysfunction. Our findings suggest a plausible model for AATD liver injury and the possibility of mechanism-based therapeutic interventions for AATD liver disease.  相似文献   
55.
Derivatives of newly synthesized aromatic polyimides containing sulphur atoms in the backbone were studied as electron–hole-transporting and light-emitting materials for use in combination with tris(8-hydroxyquinoline)-aluminium in multilayer organic electroluminescent devices. Efficient bipolar charge transport has been revealed in the polymers. Bright electroluminescence (15000cdm-2 at 14V) was observed in the visible range. The possible role of intermolecular donor–acceptor interactions in the mechanism of electroluminescence is discussed. © of SCI.  相似文献   
56.
Asphaltenes (isolated by preparative TLC) from Potiguar Basin (Brazil) crude oils were submitted to mild oxidation to disrupt their structure, releasing the occluded oil. The released hydrocarbons were compared with those from the original crude oil, in order to provide an additional insight regarding composition in biomarkers and depositional paleoenvironment. It was possible to suggest that the oil samples present low thermal evolution, marine depositional environment and anoxide. The results showed that the release of these occluded hydrocarbon, which are remnants from the original oil, can be a tool for the geochemical study of highly biodegraded oils, leading to better maturation and origin information.  相似文献   
57.
The reconstruction of large segmental defects still represents a critical issue in the orthopedic field. The use of functionalized scaffolds able to create a magnetic environment is a fascinating option to guide the onset of regenerative processes. In the present study, a porous hydroxyapatite scaffold, incorporating superparamagnetic Fe3O4 nanoparticles (MNPs), was implanted in a critical bone defect realized in sheep metatarsus. Superparamagnetic nanoparticles functionalized with hyperbranched poly(epsilon-Lysine) peptides and physically complexed with vascular endothelial growth factor (VEGF) where injected in situ to penetrate the magnetic scaffold. The scaffold was fixed with cylindrical permanent NdFeB magnets implanted proximally, and the magnetic forces generated by the magnets enabled the capture of the injected nanoparticles forming a VEGF gradient in its porosity. After 16 weeks, histomorphometric measurements were performed to quantify bone growth and bone-to-implant contact, while the mechanical properties of regenerated bone via an atomic force microscopy (AFM) analysis were investigated. The results showed increased bone regeneration at the magnetized interface; this regeneration was higher in the VEGF-MNP-treated group, while the nanomechanical behavior of the tissue was similar to the pattern of the magnetic field distribution. This new approach provides insights into the ability of magnetic technologies to stimulate bone formation, improving bone/scaffold interaction.  相似文献   
58.

A methodology for designing a tunnel support system according to the actual ground conditions and the critical behaviour types is analysed in this paper. The methodology is justified with the principles of the New Austrian Tunnelling Method that incorporates the top heading and bench method. The role of the geological material and its implication in tunnel design, reinforced with advances in site investigation methods, cannot be based solely on the development of the geotechnical classification systems and the consequent quantification of the rock masses. Support requirements for rock masses with equal classification ratings can be different. The procedure presented in this study cannot bypass the geological and/or in situ characteristics dictating or influencing the tunnel behaviour compared with a standardised classification that could miss the specifics and particularities of and around a tunnel section. The step-by-step procedure is applied in a tunnel excavated in tectonically disturbed heterogeneous flysch sediments in Serbia. The complex structure of these materials, resulting from their depositional and tectonic history that includes severe faulting and folding, presents a challenge to geologists and engineers. The possible ground types are evaluated, and then, combined with the factors of the tunnel geometry, the primary stress condition, and the water conditions, several behaviour types are considered. These classified behaviour types, followed by the suitable mechanical properties that are required for effective tunnel engineering design, are the basis for the numerical design of the appropriate primary support measures to achieve stable tunnel conditions. The twin-tube, two-lane highway tunnel was successfully constructed without significant problems.

  相似文献   
59.
The onset of stall cells (SCs) is experimentally investigated on a flattop loaded 18% thick airfoil optimized for use on wind turbine blades, exhibiting trailing edge separation. SCs are dynamic coherent vortical structures that appear on wings under separated flow conditions. Although SCs have been known for long, neither are their characteristics completely documented nor their generating mechanisms fully understood. The present investigation aims at providing additional information on the geometric characteristics in terms of width, length and occupied area. The relevant data are presented as functions of Reynolds (Re) number, angle of attack and aspect ratio (AR) of the model. In the tests reported, the dynamic character of SCs is suppressed by imposing a localized flow disturbance. For the specific airfoil and for the Re and AR range tested, it is found that: the angle of attack at which SCs are initially formed decreases linearly with Re number and independently of the AR; unlike two‐dimensional separation, their chordwise length increases with Re; the SC area relative to the wing planform area (defined as the relative SC area) grows asymptotically with angle of attack and Re number reaching an upper bound, which is independent of the AR; at intermediate angles of attack, the SC relative area is higher for the lower AR wing; for a fixed increment in Re number, the growth of the SC relative area is independent of the initial Re number; at lower angles of attack, the actual SC area is independent of the wing span. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
60.
The adoption of information systems in healthcare is no less significant than in any other commercial or caring organisation. The literature on IS adoption in healthcare, makes it clear that the actors involved in the adoption process are almost universally seen as crucial, which matches our research results too. However, how such actors should be identified remains a topic for investigatory work since these are early days in achieving this. We derive and propose a structured method to model how actors might be identified: structured because such a rationale is explicable and such a method is more readily usable when transferred to others. Our structured method, named IGOHcaps, uses a static and then a dynamic step to pull out the individual, group, organisational and human determinants of the critical actors. In this process, the individual actors' differing views emerge which could enable decision-making bodies to produce more robust proposals if they incorporated some of the appropriate views. We discuss the application of IGOHcaps through a hospital case study. While a single case study cannot be a proof, the engagement of the actors was encouraging.  相似文献   
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