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91.
对2000年欧锦赛失球情况的研究   总被引:7,自引:0,他引:7  
运用灰色关联分析法对 2 0 0 0年欧锦赛失球因素、失球区域和射门方式等进行了分析研究。结果表明盯人不紧、未封住射门路线是失球的主要因素。罚球区是失球的主要区域。  相似文献   
92.
高闯  柳林集 《档案学研究》2021,35(2):119-124
以三维模型为代表的产品数据是产品档案的重要组成部分,应进行长期归档保存。本文对空客德国公司开展产品数据归档的依据、标准、系统和流程进行了详尽的介绍,通过空客德国公司的最佳实践,阐述了其对我国工业企业开展产品数据归档的启示,以期推动我国产品数据的归档工作。  相似文献   
93.
研究目的:以中试规模的缺氧/厌氧/好氧/后缺氧污水处理工艺为研究对象,利用BioWin软件平台及其内嵌的通用活性污泥数学模型,建立该工艺的模拟模型并进行校正及验证,为优化该工艺的设计及运行提供指导。创新要点:成功建立了缺氧/厌氧/好氧/后缺氧工艺的活性污泥数学模型,甄别出对模型输出有显著影响的灵敏性参数。研究方法:通过呼吸试验获取进水水质特征,利用BioWinTM软件平台及其内嵌的通用活性污泥数学模型,建立该工艺的模拟模型,利用模型缺省值进行初步稳态模拟,借助灵敏度分析方法筛选出重要的化学计量学参数及动力学参数并进行模型校正,利用校正后的模型对该工艺进行了动态模拟。重要结论:灵敏度分析可优化模型的校正过程,该工艺出水水质对异养菌(OHOs)和氨氧化菌(AOB)(YH、μmaxH、Ks、bH、μmaxA、KNH4A和baeroa,A)的灵敏度较高。校正后的模型稳态模拟出水水质(pH、COD、TN、NH4+-N、NO2--N、NO3--N和TP)控制在与实测出水相应的95%置信区间内(图5),表明稳态模型建模成功,在此基础上运行的动态模拟准确地反映了工艺实际运行中的浓度变化趋势(图6),具有良好的模拟效果。  相似文献   
94.
如何提高热门图书的流通速度、缓解供需矛盾是国内外图书馆研究的热点并提出了诸多解决方案,其中调整图书的借阅期限是最常用的解决方案,通过对现有的多种图书借阅期限调整方法及其优缺点进行归纳分析,在图书弹性借期制的基础上,提出了一种新的图书借期调整方法,建立了基于预约申请量的图书借期动态调整模型,以期能够满足读者的借阅需求,改善借阅体验。  相似文献   
95.
文章介绍与评论了在高能物理学、智能科学、生物科学和社会科学等学科的前沿领域中,哲学与科学跨学科研究的近况。在简要说明了这些学科的哪些前沿问题与哲学发生了相互碰撞的同时,也介绍了近年来这些方面在国际上出现的交叉研究机构与人物。  相似文献   
96.
This paper presents neural networks based on command filtering control method for a table-mount experimental helicopter which has three rotational degrees-of-freedom. First, the controller is designed based on backstepping technique, and further command filtering technique is used to solve the derivative of the virtual control, thereby avoiding the effects of signal noise. Secondly, the model uncertainty of the table-mount experimental helicopter’s system is estimated by using neural networks. And then, Lyapunov stabilization analysis proves the stability of the table-mount experimental helicopter closed-loop attitude tracking system. Finally, the experiment is carried out to clarify the effectiveness of the proposed method.  相似文献   
97.
In this study, a total sliding-mode-based particle swarm optimization control (TSPSOC) scheme is designed for the periodic motion control of an indirect field-oriented linear induction motor (LIM) drive. First, an indirect field-oriented mechanism for a LIM drive is introduced to preserve the decoupling control characteristic. Then, the concept of total sliding-mode control (TSC) is incorporated into particle swarm optimization (PSO) to form an on-line TSPSOC framework for preserving the robust control characteristics and reducing the chattering control phenomena of TSC. Moreover, an adaptive inertial weight is devised to accelerate the searching speed effectively. In this control scheme, a PSO control system is utilized to be the major controller, and the stability can be indirectly ensured by the concept of TSC without strict constraint and detailed system knowledge. With the proposed TSPSOC system, the mover position of the controlled LIM drive possesses the advantages of favorable robust characteristic, control effort without chattering, and simple control framework. Numerical simulations and experimental results are given to verify the effectiveness of the proposed control scheme for the tracking of periodic reference trajectories. In addition, the superiority of the proposed TSPSOC scheme is indicated in comparison with the TSC, Petri fuzzy-neural-network control (PFNNC) and traditional fuzzy-neural-network control (TFNNC) systems.  相似文献   
98.
Quantifying the motility of micro-organisms is beneficial in understanding their biomechanical properties. This paper presents a simple image-based algorithm to derive the kinetic power and propulsive force of the nematode Caenorhabditis elegans. To avoid unnecessary disturbance, each worm was confined in an aqueous droplet of 0.5 μl. The droplet was sandwiched between two glass slides and sealed with mineral oil to prevent evaporation. For motion visualization, 3-μm fluorescent particles were dispersed in the droplet. Since the droplet formed an isolated environment, the fluid drag and energy loss due to wall frictions were associated with the worm''s kinetic power and propulsion. A microparticle image velocimetry system was used to acquire consecutive particle images for fluid analysis. The short-time interval (Δt < 20 ms) between images enabled quasi real-time measurements. A numerical simulation of the flow in a straight channel showed that the relative error of this algorithm was significantly mitigated as the image was divided into small interrogation windows. The time-averaged power and propulsive force of a N2 adult worm over three swimming cycles were estimated to be 5.2 ± 3.1 pW and 1.0 ± 0.8 nN, respectively. In addition, a mutant, KG532 [kin-2(ce179) X], and a wild-type (N2) worm in a viscous medium were investigated. Both cases showed an increase in the kinetic power as compared with the N2 worm in the nematode growth medium due to the hyperactive nature of the kin-2 mutant and the high viscosity medium used. Overall, the technique deals with less sophisticated calculations and is automation possible.  相似文献   
99.
The purpose of this study is describe the initial feasibility, reliability, and validity of an instrument to measure physical activity in preschoolers using direct observation. The System for Observing Fitness Instruction Time for Preschoolers was developed and tested among 3- to 6-year-old children over fall 2008 for feasibility and reliability (Phase I, n=67) and in fall 2009 for concurrent validity (Phase II, n=27). Phase I showed that preschoolers spent >75% of their active time at preschool in light physical activity. The mean inter-observer agreements scores were ≥.75 for physical activity level and type. Correlation coefficients, measuring construct validity between the lesson context and physical activity types with and with the activity levels, were moderately strong. Phase II showed moderately strong correlations ranging from .50 to .54 between the System for Observing Fitness Instruction Time for Preschoolers and Actigraph accelerometers for physical activity levels. The System for Observing Fitness Instruction Time for Preschoolers shows promising initial results as a new method for measuring physical activity among preschoolers.  相似文献   
100.
目的:压缩指数是软土工程领域的关键参数。本文旨在提出一个基于进化多项式回归和实编码遗传算法(EPR-RCGA)的回归分析方法,将压缩指数与物理特性建立相关关系并应用于工程实践。创新点:结合EPR和RCGA方法,将中国沿海21个不同区域的黏土的压缩性指数与天然含水率和液塑限之间建立相关关系,并采用均方根误差(RMSE)、赤池信息量准则(AIC)和贝叶斯信息准则(BIC)对所建立的不同回归模型进行优选。方法:1.从文献中收集中国沿海21个地区的黏土的压缩指数和常见的基本物理性质,并对数据进行整理和分类。2.进行压缩指数和天然含水量及液塑限之间的EPR回归关系分析,并采用新近提出的RCGA优化方法来提高回归关系的精度。3.采用RMSE、AIC和BIC对不同组合下的回归关系进行优选,并确定最佳回归关系。4.将得到的关系式应用到有限元路堤计算来验证所得关系式的实用性和准确性。结论:1.本文提出的压缩指数关系式比现有的经验公式更好,预测得到的压缩指数更为精确。2.采用所提出的压缩指数回归模型预测了东南沿海一路堤下不同土层的压缩指数,并应用所得数据和有限元方法对路堤的沉降进行了模拟分析,验证了所提方法的可靠性。3.所有结果表明,结合基于EPR和RCGA的回归分析方法以及基于RMSE、AIC和BIC的模型选择方法对分析压缩指数与黏土的物理性质的相关关系是切实可行的,可以更好地服务于中国沿海地区的工程设计。  相似文献   
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