全文获取类型
收费全文 | 254篇 |
免费 | 16篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 76篇 |
金属工艺 | 3篇 |
机械仪表 | 11篇 |
建筑科学 | 10篇 |
能源动力 | 5篇 |
轻工业 | 14篇 |
水利工程 | 6篇 |
无线电 | 33篇 |
一般工业技术 | 49篇 |
冶金工业 | 18篇 |
原子能技术 | 4篇 |
自动化技术 | 38篇 |
出版年
2023年 | 5篇 |
2022年 | 3篇 |
2021年 | 18篇 |
2020年 | 9篇 |
2019年 | 13篇 |
2018年 | 8篇 |
2017年 | 14篇 |
2016年 | 10篇 |
2015年 | 11篇 |
2014年 | 5篇 |
2013年 | 25篇 |
2012年 | 12篇 |
2011年 | 32篇 |
2010年 | 17篇 |
2009年 | 17篇 |
2008年 | 12篇 |
2007年 | 17篇 |
2006年 | 2篇 |
2005年 | 6篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 3篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1978年 | 1篇 |
排序方式: 共有270条查询结果,搜索用时 15 毫秒
81.
Eduarda Filipe 《International Journal of Thermophysics》2008,29(3):871-880
Experimental design is a statistical tool concerned with the planning of experiments to obtain the maximum amount of information
from the available resources. This tool may be applied to metrology, especially for the analysis of a large number of repeated
measurements (replicates) of short-term repeatability and the medium-term and long-term reproducibilities, enabling the inclusion
of these “time-dependent sources of variability” in the uncertainty budget. The realization of the International Temperature
Scale of 1990 (ITS-90) scale requires that laboratories usually have more than one cell for each fixed point, for comparison
on a regular basis. The calculation of the uncertainty of such comparisons is considered here, taking into account these time-dependent
sources of variability. These components of the uncertainty evaluated by a Type A method are obtained by the statistical analysis
of the experimental results using the components of a variance model for designs consisting of nested or hierarchical sequences
of measurements, as foreseen by the mainstream GUM. An application example of a balanced nested structure in the comparison
of two fixed-point cells is presented. 相似文献
82.
Tânia A. F. Rodrigues Filipe J. P. Chaves Lucas F. M. da Silva Marcelo Costa Ana Q. Barbosa 《Materialwissenschaft und Werkstofftechnik》2017,48(11):1181-1190
Adhesive joints in the transportation industry may be exposed to aggressive environments such as humidity during their service life, which may influence their reliability. This research aims to determine the fracture toughness of aluminium bonded joints under pure mode I, pure mode II and mixed mode I and II loadings in dry and wet condition, with the main purpose to predict the influence of humidity in the toughness properties of an adhesive. It was found that water does influence the fracture mechanics properties, increasing mode I fracture toughness and decreasing mode II fracture toughness. 相似文献
83.
E. Filipe S. Gentil I. Lóio R. Bosma A. Peruzzi 《International Journal of Thermophysics》2018,39(2):26
Interpolation error is a major source of uncertainty in the calibration of standard platinum resistance thermometer (SPRT) in the subranges of the International Temperature Scale of 1990 (ITS-90). This interpolation error arises because the interpolation equations prescribed by the ITS-90 cannot perfectly accommodate all the SPRTs natural variations in the resistance–temperature behavior, and generates different forms of non-uniqueness. This paper investigates the type 3 non-uniqueness for fourteen SPRTs of five different manufacturers calibrated over the water–zinc subrange and demonstrates the use of the method of divided differences for calculating the interpolation error. The calculated maximum standard deviation of 0.25 mK (near \(100\,^{\circ }\hbox {C}\)) is similar to that observed in previous studies. 相似文献
84.
Pedro Arsnio Patricia María Rodríguez‐Gonzlez Ivan Bernez Filipe S. Dias Miguel N. Bugalho Simon Dufour 《河流研究与利用》2020,36(6):907-920
Social‐ecological contexts are key to the success of ecological restoration projects. The ecological quality of restoration efforts, however, may not be fully evident to stakeholders, particularly if the desired aesthetic experience is not delivered. Aesthetically pleasing landscapes are more highly appreciated and tend to be better protected than less appealing landscapes, regardless of their ecological value. Positive public perception of restoration actions may therefore facilitate stakeholder involvement and catalyse recognition of ecological improvement. Here we aim to contrast aesthetical perception and ecological condition in headwater river reaches restored through passive ecological restoration in study areas in Portugal (Alentejo) and France (Normandy). We recorded structural and functional indicators of riparian vegetation to monitor the ecological condition of study sites along a passive restoration trajectory. Aesthetical perception indicators were assessed through stakeholder inquiries developed under a semantic differential approach. We analysed perception responses to changes in the riparian ecosystems resulting from passive ecological restoration across different geographical contexts and social groups. The analysed social groups comprised stakeholders (environmental managers and landowners) and university students (landscape architecture and geography students). Results indicate that (a) visual preferences often do not reflect changes in ecological condition, (b) perception of the restoration process is strongly context dependent, and (c) experience and cultural background affect perception of ecological condition across the different social groups analysed. Clear identification of relevant stakeholder groups (those interested in or directly affected by restoration), effective communication, and stakeholder engagement are therefore essential for assuring the success of river restoration projects. 相似文献
85.
Georgia Penido Safe Claudionor Coelho Jr. Luiz Filipe M. Vieira Celina Gomes Do Val Jose Augusto Nacif Antonio Otavio Fernandes 《International Journal on Software Tools for Technology Transfer (STTT)》2012,14(1):95-108
Functional verification is “the” major design-phase bottleneck for silicon productivity. Since functional verification is
an NP-complete problem, it relies on a large number of heuristics with associated parameters (engines). With the advent of
parallel processing, formal verification can be optimized by selecting the best n engines to run in parallel, increasing the chance of reaching successful termination of the verification task. In this paper,
we will present a methodology to build engine estimators based on structural metrics and to select n engines to run in parallel. The methodology considers both engines’ estimated performance and engines’ correlation. Results
confirmed that the methodology can be a very quick selection mechanism for parallelization of engines in order to increase
the chance of running the best engines to solve the problem. 相似文献
86.
Habib Shazma Serwar Monazza Rana Usman Ali Siddiqi Humaira M. Arif Saira Coca-Clemente Jose A. Braga Filipe 《Iranian Polymer Journal》2021,30(10):1029-1039
Iranian Polymer Journal - The hazardous industrial effluent, enriched in organic dyes, produces environmental alarms of being resistant to natural degradation processes. Therefore, the development... 相似文献
87.
A new method for the fabrication of microstructured polymer surfaces possessing features with different 3D geometries is reported. Controlled micromolding using masters with 2D topographies and fluid elastomeric precursors with various viscosities and crosslinking kinetics yielded homogeneously structured surfaces possessing microtubes and concave and convex hemispheres with defined dimensions. This fabrication strategy does not require sophisticated 3D structuring equipment and can be extended to other materials, dimensions and geometries. 相似文献
88.
Filipe MagalhãesÁlvaro Cunha 《Mechanical Systems and Signal Processing》2011,25(5):1431-1450
This tutorial paper aims to introduce the topic of operational modal analysis to non-specialists on the subject. First of all, it is stressed the relevance of this experimental technique particularly in the assessment of important civil infrastructure. Then, after a synthesis of required theoretical background, three of the most powerful algorithms for output-only modal identification are presented. The several steps of these identification procedures are illustrated with the processing of data collected on a concrete arch bridge with a span of 280 m. As the use of operational modal analysis in the context of structural health monitoring is a subject under active research, this theme is also introduced and briefly exemplified with data continuously recorded at the same bridge. 相似文献
89.
Gheorghe Cosmin Silaghi Filipe Araujo Luis Moura Silva Patricio Domingues Alvaro E. Arenas 《Journal of Grid Computing》2009,7(4):555-573
Desktop Grid systems reached a preeminent place among the most powerful computing platforms in the planet. Unfortunately,
they are extremely vulnerable to mischief, because computing projects exert no administrative or technical control on volunteers.
These can very easily output bad results, due to software or hardware glitches (resulting from over-clocking for instance),
to get unfair computational credit, or simply to ruin the project. To mitigate this problem, Desktop Grid servers replicate
work units and apply majority voting, typically on 2 or 3 results. In this paper, we observe that simple majority voting is
powerless against malicious volunteers that collude to attack the project. We argue that to identify this type of attack and
to spot colluding nodes, each work unit needs at least 3 voters. In addition, we propose to post-process the voting pools in two steps. i) In the first step, we use a statistical approach to identify nodes that were not colluding, but submitted bad results; ii) then, we use a rather simple principle to go after malicious nodes which acted together: they might have won conflicting
voting pools against nodes that were not identified in step i. We use simulation to show that our heuristic can be quite effective against colluding nodes, in scenarios where honest nodes
form a majority. 相似文献
90.
This paper examines the feasibility of using multivariate statistics to model fish species distribution and habitat requirements for intermittent streams in semi‐arid regions, many of which are coming under increasing pressure from water resource development schemes. The assessment was based on the geographical distribution of six endemic fish species in the Guadiana river, a semi‐arid river system in southern Iberia. Their presence was related to 20 environmental variables linked to climate, geomorphology, riparian vegetation and location in the drainage basin. These variables were collected in the field or from topographical maps to evaluate habitat suitability and to predict the presence of the species according to season. Multivariate logistic regression in a geographic information system (GIS) environment was performed to identify regions with high probability of occurrence for each species. The variables that best explained the occurrence of the species were the sample location in the drainage basin, the geomorphology and the riparian vegetation. The models presented have a high predictive power and can be used in monitoring and predicting temporal changes caused by human activities. This modelling approach can be used to predict the areas that need to be conserved to protect or rehabilitate the endangered species. Armed with this information, managers can formulate conservation measures to prevent further degradation of the stocks and possibly enhance the populations. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献