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31.
32.
In the real world, projects are subject to numerous uncertainties at different levels of planning. Fuzzy project scheduling is one of the approaches that deal with uncertainties in project scheduling problem. In this paper, we provide a new technique that keeps uncertainty at all steps of the modelling and solving procedure by considering a fuzzy modelling of the workload inspired from the fuzzy/possibilistic approach. Based on this modelling, two project scheduling techniques, Resource Constrained Scheduling and Resource Leveling, are considered and generalized to handle fuzzy parameters. We refer to these problems as the Fuzzy Resource Constrained Project Scheduling Problem (FRCPSP) and the Fuzzy Resource Leveling Problem (FRLP). A Greedy Algorithm and a Genetic Algorithm are provided to solve FRCPSP and FRLP respectively, and are applied to civil helicopter maintenance within the framework of a French industrial project called Helimaintenance. 相似文献
33.
In this paper, we have collected the requirements for Digital Rights Management from various sources, and presented them as
a set of 11 requirements, associated with five categories. We discuss each requirement, provide the motivation for each entry,
and illustrate how each one could be achieved. Four example commercial DRM systems are briefly explained, and the requirements
that they meet are presented in tabular format. None of the example systems meet all the requirements that we have listed.
The security threats that are faced by DRM systems are briefly discussed. All of the example systems are based on unicast
data distribution. The use of multicast data distribution can help the source of the data and the underlying network to reduce
their resource requirements when distributing high-quality content at minimum cost and delay. Up to now, there has been little
motivation to use standard Internet Protocol multicast because it does not support any protection mechanisms for the delivered
data. Given that significant progress has been made by other researchers in providing “secure” multicast data distribution,
we explore how the use of secure multicast as a distribution technology can bring significant improvement for some requirements,
while making the achievement of others more difficult. We review how the architecture of the distribution must change to permit
capturing the advantages of multicast distribution while retaining as much as possible the features of unicast systems. Some
open problems are identified. 相似文献
34.
M. Sahli C. Millot C. Roques-Carmes C. Khan Malek T. Barriere J.C. Gelin 《Journal of Materials Processing Technology》2009,209(18-19):5851-5861
This paper describes observations and metrological analyses made to compare the replication quality of polymeric replicas obtained by filling micro-cavities using both hot embossing and micro-injection moulding processes. The experiments are performed with polypropylene (PP) at a constant melt temperature and a constant mould temperature, whereas hot embossing tests are carried out with the same polymer at temperatures close to the softening one.The results concerning the micro-cavities filling provide information on the reliability about the possibilities of replication topographical surface geometries. The data obtained by scanning mechanical microscopy (SMM) are used to determine the comparative filling ratio values. 相似文献
35.
The X-ray micromachining activities at CAMD are described. Through the HI-MEMS Alliance Program, CAMD has developed an extensive
technical infrastructure and process experience. The “X-ray Print-Shop” supports prototyping and is prepared for cost effective
low-to-medium volume production of primary parts with high aspect ratio, including exposure of multiple level devices with
alignment, as well as tilted and rotated exposures. Important lessons learnt during the course of the program will be reported.
An up-grade of the facility to install a 7.5 Tesla superconducting wiggler in the ring is in progress. It will produce hard
X-rays for ultra-deep X-ray lithography.
Received: 25 August 1997/Accepted: 3 September 1997 相似文献
36.
Recently, measurement-based studies of software systems have proliferated, reflecting an increasingly empirical focus on system availability, reliability, aging, and fault tolerance. However, it is a nontrivial, error-prone, arduous, and time-consuming task even for experienced system administrators, and statistical analysts to know what a reasonable set of steps should include to model, and successfully predict performance variables, or system failures of a complex software system. Reported results are fragmented, and focus on applying statistical regression techniques to monitored numerical system data. In this paper, we propose a best practice guide for building empirical models based on our experience with forecasting Apache web server performance variables, and forecasting call availability of a real-world telecommunication system. To substantiate the presented guide, and to demonstrate our approach in a step by step manner, we model, and predict the response time, and the amount of free physical memory of an Apache web server system, as well as the call availability of an industrial telecommunication system. Additionally, we present concrete results for a) variable selection where we cross benchmark three procedures, b) empirical model building where we cross benchmark four techniques, and c) sensitivity analysis. This best practice guide intends to assist in configuring modeling approaches systematically for best estimation, and prediction results. 相似文献
37.
All persons 65 years and older are recommended to be immunised against influenza each autumn. As immunisation rates remain low, we conducted a randomised control trial in a three-partner urban general practice to evaluate the differential effectiveness of a single postcard reminder in a general practice setting compared to usual care. All non-residential patients aged 65 years and over were identified from the age/sex/disease register. After exclusions, 325 patients were stratified by sex (125 men and 200 women) and randomised to receive either a postcard reminder in large print mailed in April or usual care. General practitioners (GPs) were blind to the randomisation. A blinded record audit performed in July demonstrated that the postcard was effective in increasing immunisation for men (chi(2)1df = 3.85; p = 0.05) but not for women (chi(2)1df = 0.45; p = 0.50). After adjusting for 1995 immunisation status, the effect of the postcard on immunisation rates was even stronger in men (Wald chi(2)1df = 6.20; p = 0.01) but remained non-significant in women (Wald chi(2)1df = 1.38; p = 0.24). With this adjustment, the odds of having the 1996 flu vaccine for men sent the postcard reminder were three times that of men in the control group (OR = 3.0; 95% CI 1.3-6.9). In a general practice setting, a single postcard reminder appears to be a promising way to boost influenza immunisation rates among ageing men. Replication of the study is recommended. 相似文献
38.
A new reconfigurable systolic multicomputer architecture is presented. The proposed architecture, called the Cylindrical Banyan Multicomputer (CBM), is based on the structure of a modified banyan network where every node of the network graph is composed of an application processor, a local memory and a communication processor, and network's inputs and outputs are merged (fused). The CBM has one of the lowest (cost) X (delay) among known multicomputer architectures based on regular networks. It is shown that a variety of computation structures such as pipelines, rings, and trees may be constructed and reconfigured in an optimal or a nearby optimal way on the CBM architecture, and that various basic algorithms can be executed very efficiently in a systolic manner. It is also shown that the CBM is an easily diagnosable and fault-tolerant system. 相似文献
39.
40.
Analyzing Large Scale Real-World Wireless Multihop Network 总被引:1,自引:0,他引:1
We present the results of analysis of Berlin's free multihop wireless network and provide topological, link reliability and traffic statistics we have captured from it. The network is relatively large compared with known wireless multihop networks and testbeds, and it had 316 participating nodes on the average. The observed properties are different from frequently used models: the network is connected but with low average node density, it has large number of bridges (some of them with very low quality of links) and the traffic distribution is highly asymmetrical. 相似文献