全文获取类型
收费全文 | 2775篇 |
免费 | 333篇 |
国内免费 | 135篇 |
学科分类
工业技术 | 3243篇 |
出版年
2024年 | 11篇 |
2023年 | 47篇 |
2022年 | 61篇 |
2021年 | 62篇 |
2020年 | 80篇 |
2019年 | 54篇 |
2018年 | 51篇 |
2017年 | 94篇 |
2016年 | 106篇 |
2015年 | 116篇 |
2014年 | 251篇 |
2013年 | 204篇 |
2012年 | 275篇 |
2011年 | 287篇 |
2010年 | 223篇 |
2009年 | 223篇 |
2008年 | 170篇 |
2007年 | 205篇 |
2006年 | 187篇 |
2005年 | 139篇 |
2004年 | 104篇 |
2003年 | 81篇 |
2002年 | 47篇 |
2001年 | 46篇 |
2000年 | 30篇 |
1999年 | 24篇 |
1998年 | 12篇 |
1997年 | 11篇 |
1996年 | 5篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
排序方式: 共有3243条查询结果,搜索用时 15 毫秒
1.
为探讨太白金矿回收原采场边部残余低品位矿体的方案,通过层次分析法(AHP)与模糊数学(FUZZY)理论,选取对残采工程影响较大的9个因素,建立优选模型。运用层次分析法确定了各评价指标的权重;采用模糊数学法分析计算各采矿方法的定性、定量指标,分别得到各评价指标的隶属度。最终计算出3种工程布置方案的综合优选度分别为68.1%、69.3%、58.1%,从而沿矿体走向双进路布置确定为最优开采方案。实践表明,采用该模型优选的工程布置方案具有一定的科学性、合理性,值得借鉴与推广。 相似文献
2.
Significant emergency measures should be taken until an emergency event occurs. It is understood that the emergency is characterized by limited time and information, harmfulness and uncertainty, and decision-makers are always critically bound by uncertainty and risk. This paper introduces many novel approaches to addressing the emergency situation of COVID-19 under spherical fuzzy environment. Fundamentally, the paper includes six main sections to achieve appropriate and accurate measures to address the situation of emergency decision-making. As the spherical fuzzy set (FS) is a generalized framework of fuzzy structure to handle more uncertainty and ambiguity in decision-making problems (DMPs). First, we discuss basic algebraic operational laws (AOLs) under spherical FS. In addition, elaborate on the deficiency of existing AOLs and present three cases to address the validity of the proposed novel AOLs under spherical fuzzy settings. Second, we present a list of Einstein aggregation operators (AgOp) based on the Einstein norm to aggregate uncertain information in DMPs. Thirdly, we are introducing two techniques to demonstrate the unknown weight of the criteria. Fourthly, we develop extended TOPSIS and Gray relational analysis approaches based on AgOp with unknown weight information of the criteria. In fifth, we design three algorithms to address the uncertainty and ambiguity information in emergency DMPs. Finally, the numerical case study of the novel carnivorous (COVID-19) situation is provided as an application for emergency decision-making based on the proposed three algorithms. Results explore the effectiveness of our proposed methodologies and provide accurate emergency measures to address the global uncertainty of COVID-19. 相似文献
3.
Aircraft maintenance organisation is a complex socio-technical setup, where human factors influence the quality of aircraft maintenance service. Maintenance service quality is assessed based on the commitment of management and its ability to provide suitable facility, tools, spares and manpower supported with comfortable environment and maintenance procedures. Assessment of the service quality of the aircraft maintenance organisation is a complex process. Airlines, regulators, insurance companies and other agencies need decision support system, to assess the performance of a maintenance organisation. This paper provides criteria and scientific approach for assessing the maintenance organisation; it presents a methodology of applying Analytical Hierarchy Process to prioritise the key functions and to rank the maintenance organisations under study. The study has established that maintenance service quality in airline is directly correlated to its fleet size. 相似文献
4.
Reverse logistics practices are gaining attention due to industrial ecology, enforced legislation and corporate citizenship but presence of barriers make reverse logistics (RL) implementation difficult and hence reduce the success rate. To increase RL adoption, robust and flexible strategies are required to overcome its barriers. This study focuses on identification and ranking the solutions of reverse logistics adoption in electronics industry to overcome its barriers. It aids firms to ponder on high rank solutions and develop strategies to implement them on priority. This paper proposes a methodology based on fuzzy analytical hierarchy process (AHP) and fuzzy technique for order performance by similarity to ideal solution (TOPSIS) to identify and rank the solutions of RL adoption to overcome its barriers. Fuzzy AHP is applied to get weights of the barriers as criteria by pairwise comparison and final ranking of the solutions of RL adoption is obtained through fuzzy TOPSIS. The empirical case of Indian electronics industry is shown to illustrate the use of the proposed method. This proposed method offers a more precise, efficient and effective decision support tool for stepwise implementation of the solutions due to consideration of fuzzy environment. Finally sensitivity analysis is performed to illustrate the robustness of the method. 相似文献
5.
ChunFang Song Guiyi Luo Tian Sang Zhenfeng Li Wanxiu Xu G. S. V. Raghavan 《Drying Technology》2018,36(14):1678-1687
Due to the limitations of single index analysis, the merits and demerits of microwave-assisted permeation process cannot be comprehensively evaluated. However, the analytical hierarchy process (AHP) was applied to optimize the conditions of microwave-assisted diffusion of sugar in blackberry. In this paper, the results of a single-factor experiment were compared with blackberry preserved after the treatment of microwave. An orthogonal rotation test procedure was designed to calculate the composite score of preserved blackberry fruit using AHP, and to determine the optimum processing conditions based on sugar osmosis characteristics. The results showed that the sugar content, vitamin C (VC) content, and color difference of treated blackberry increased with the increase of microwave power, the residence time, and the resulting sugar concentration. The composite grade points are listed to show that the optimum results were as follows: power level, the residence time, and the sugar concentration were, respectively, 210?W, 12?min, and 35%. 相似文献
6.
It is of great practical significance to optimise the decision-making of cloud manufacturing service providers, which can ensure the efficient operation of the cloud manufacturing services. In order to effectively optimise, this paper constructs the evaluation index system, sorts out 7 important evaluation indexes. A method is proposed on the basis of the TOPSIS method and Grey Correlation Analysis (GRA), which is a decision-making method combining static distance and dynamic trend, and make the evaluation results more reasonable. In addition, in order to reflect the true weight of the high dimensional index, the evaluation model of projection pursuit index is established. The improved Particle Swarm Optimisation (PSO) algorithm is used to optimise the projection index function and model parameters, and to obtain the objective weights of evaluation indexes. Then the objective weights combine with the subjective weights obtained by the Analytic hierarchy process (AHP), which makes the weights of the evaluation indexes achieve the unity of subjective and objective. Finally, 20 sets of simulation examples are given to illustrate the feasibility and effectiveness of the proposed method. 相似文献
7.
8.
AHP法用于大气环境评价 总被引:1,自引:0,他引:1
本文根据AHP原理,以GB3095-82大气环境质量标准作为基础,对大气环境质量进行综合评价。方法快速、简便,适合于多采样点多污染因子的评价任务。 相似文献
9.
10.
矿产资源及其开采条件风险是矿业项目投资风险之根源.因此。分析了矿业项目投资风险时,合理估计矿产资源及其开采条件风险是至关重要的。针对矿产资源及其开采条件风险评价难以做到客观、全面、精确的问题,提出了矿产资源及其开采条件风险的模糊综合评判方法,建立了系统、全面的矿产资源及其开采条件风险评价指标体系,运用AHP法构建了风险评价的递阶层次结构,递阶层次分为3层:目标层、准则层(主因素层)和指标层(子因素层),并通过两两比较求出各指标的权重,进而建立了适用于矿产资源及其开采条件风险定量评价的多级模糊综合评判数学模型。 相似文献