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1.
High moisture mozzarella from cow milk is a pasta filata cheese that can be manufactured by different protocols. Fermentation by autochthonous starter is used for the traditional product, whereas direct acidification with citric acid is widely used at industrial level. Both types are stored immersed in a liquid for preserving freshness, but this packaging method is known to favour the changes of the quality characteristics. The present study aimed to assess the evolution of the soluble compounds and to evaluate their use as chemical indices for discriminating the two types of mozzarella. The contents of lactose, organic acids, water-soluble nitrogen and free amino acids differently changed over time. The whole patterns of these soluble compounds allowed discrimination of the two products during the whole storage period. The simple analyses of lactic acid and lactose could be a rapid tool to protect traditional mozzarella from industrial imitations obtained with citric acid.  相似文献   
2.
Attribute reduction is viewed as an important preprocessing step for pattern recognition and data mining. Most of researches are focused on attribute reduction by using rough sets. Recently, Tsang et al. discussed attribute reduction with covering rough sets in the paper (Tsang et al., 2008), where an approach based on discernibility matrix was presented to compute all attribute reducts. In this paper, we provide a new method for constructing simpler discernibility matrix with covering based rough sets, and improve some characterizations of attribute reduction provided by Tsang et al. It is proved that the improved discernibility matrix is equivalent to the old one, but the computational complexity of discernibility matrix is relatively reduced. Then we further study attribute reduction in decision tables based on a different strategy of identifying objects. Finally, the proposed reduction method is compared with some existing feature selection methods by numerical experiments and the experimental results show that the proposed reduction method is efficient and effective.  相似文献   
3.
We have developed a decision support application for the Dutch Aviation Police and Air Support unit for routing their helicopters in anticipation of unknown future incidents. These incidents are not known in advance, yet do require a swift response. A response might include the dispatch of a police helicopter to support the police on the ground. If a helicopter takes too long to arrive at the crime scene, it might be too late to assist. Hence, helicopters have to be proximate when an incident happens to increase the likelihood of being able to support the police on the ground in apprehending suspects. We propose the use of a forecasting technique, followed by a routing heuristic to maximize the number of incidents where a helicopter provides a successful assist. We have implemented these techniques in a decision support application in collaboration with the Dutch Aviation Police and Air Support. Using numerical experiments, we show that our application has the potential to improve the success rate with a factor nine. The Dutch Air Support and Aviation Police are now using the application.  相似文献   
4.
基于Abaqus软件对某款轻型客车的侧围蒙皮在外力作用下凹陷的过程进行了模拟仿真,对其抗凹性及影响因素进行了分析和评价,据此提出了相应的改进措施,提高了设计质量。  相似文献   
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姚金  韩会丽  印万忠 《金属矿山》2016,45(12):66-70
为解决东鞍山磁选混合精矿中细粒菱铁矿黏附罩盖在粗颗粒赤铁矿和石英等矿物表面造成浮选指标下降的问题。考察了在分步浮选第一步浮选中添加分散剂对菱铁矿正浮选的影响,以期找到适宜的分散剂来促进矿浆的分散,改善浮选指标。结果表明,添加分散剂有利于矿浆的分散,提高浮选指标。对混磁精以柠檬酸为分散剂首先进行菱铁矿正浮选,正浮选尾矿经1粗1精2扫赤铁矿闭路反浮选,最终获得铁品位为67.89%、回收率为69.35%的铁精矿。  相似文献   
7.
覆盖层在无底柱分段崩落采矿法开采中起着重要作用,既要为挤压爆破和端部放矿创造必要条件,还需保证崩落法生产的安全性,选择合适的覆盖层厚度对矿山开采具有重要意义。首先,根据金山店铁矿东区采场结构参数,利用椭球体放矿理论计算出合理覆盖层厚度为20 m,并以覆盖层充当缓冲层时覆盖层厚度计算公式验证了该厚度能满足安全要求;其次,利用PFC~(3D)数值模拟软件进行三轴压缩试验找到与金山店铁矿东区岩体力学强度参数相匹配的矿岩颗粒微观参数;最后,根据矿岩微观参数建立放矿数值分析模型,通过选取的不同覆盖层厚度进行模拟放矿,依据放矿后矿石的回收率和贫化率大小来分析覆盖层厚度对开采指标的影响,认为20 m厚度覆盖层条件下的矿石回收率和贫化率达到最优值。理论计算和数值分析表明,金山店铁矿东区崩落法开采时覆盖层厚度取20 m,可取得较好的技术经济效果并保证采场安全。  相似文献   
8.
The main objective of this paper was to examine the overall moisture behaviour of an in situ cast concrete ground slab during the initial drying period of the fresh concrete from casting to flooring. This article describes and evaluates various methods to measure moisture levels in concrete slabs in order to decide if flooring can be attached. The most accurate method is verified against measurements and compared with calculations. Many of the methods only consider the surface moisture content of the slab and do not consider the moisture condition deep in the slab. According to performed laboratory tests and FE modelling, moisture content of the slab surface is not a reliable indicator of the overall moisture conditions of the slab. Residual moisture deep in the slab has a major effect on the moisture distribution at the slab cross-section after flooring. The only reliable method to determine the moisture conditions in a new concrete ground slab before flooring is to measure the moisture content at the equivalent depth of the slab. It reliably predicts the ultimate moisture content at slab/flooring interface after flooring. A ground slab is drying in two directions: towards the indoor air by evaporation from the slab surface, and towards the cooler subsoil layers by diffusion. The significance of drying downwards increases after the flooring assembly.  相似文献   
9.
Covering location models consider a demand “covered” if there is at least one facility sited within a preset threshold distance. If more than one facility satisfies this criterion, it is implicitly assumed that one of these facilities - usually the closest - will serve the customer, while the remaining ones will have no relation to the demand. However, there are cases in which this multiple coverage has either synergetic or undesired effects. In digital television broadcast networks using Single Frequency Network transmissions, if a customer receives transmissions from more than one transmitter, the strongest transmitter is the main signal source, while the second and following transmitters can either contribute to a good reception or act as sources of interference, depending on the technology and their relative locations. In this case, facilities should be located so as to avoid overlapping coverage if there is interference, or enhancing overlapping coverage if signals are combined constructively. We propose models that are solved using a commercial software, that address this problem. One of these models is used to compare different alternatives of network design for a region in Chile, and to find the best coverage situations.  相似文献   
10.
This paper addresses the facility location problem that aims to optimize the location and scale of a new facility in consideration of customer restrictions, including customer preference and the minimum number of customers required to open the facility. In a classic covering problem, the customer is assumed to be covered if he/she is located within the critical distance zone around the facility and is otherwise not covered. This problem is caused by customer facility selection, which differs from the classic covering problem in which services are determined only by proximity. This paper proposes a mixed integer programming formulation based on customer restrictions and also develops a heuristic solution procedure using Lagrangian relaxation. The suggested solution procedure is shown to yield acceptable results in a reasonable computation time.  相似文献   
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