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611.
A grid service composite process is made up of complex coordinative activities. Developing the appropriate model of grid service coordinative activities is an important foundation for the grid service composition. According to the coordination theory, this paper elaborates the process of the grid service composition by using UML 2.0, and proposes an approach to modelling the grid service composition process based on the coordination theory. This approach helps not only to analyze accurately the task activities and relevant dependencies among task activities, but also to facilitate the adaptability of the grid service orchestration to further realize the connectivity, timeliness, appropriateness and expansibility of the grid service composition.  相似文献   
612.
采用共沉淀法制备了Gd(1-x)2(MoO4)3:Eu3+(x=0.05,0.1,0.2,0.4,0.6,0.8)荧光粉,通过对样品的X射线衍射谱(XRD)分析,对样品的结构进行了表征.对各样品的发射光谱和激发光谱进行了测试和分析.结果表明,Gd2(MoO4)3:Eu3+荧光粉有潜力成为高效的近紫外(蓝光)激发白光LED用红色荧光粉材料.  相似文献   
613.
存货质押融资业务最优清算策略   总被引:5,自引:2,他引:3  
研究了存货质押融资业务中企业违约后银行高效率、低成本清算质押存货的最优清算策略.构建了银行的损失效用函数,使用最优控制理论,获得了使得银行损失效用函数最小化的最优清算策略,并给出了相关参数的敏感性分析及算例分析.研究得出针对不同数量的质押存货所应采取的最优清算策略以及内生的最优清算时间.  相似文献   
614.
提出了基于Tent映射的混沌差分进化算法。以某飞机纵向短周期系统为例,首次研究了基于混沌差分进化算法的飞机等效系统的拟配,克服了一些传统的拟配算法存在的一些缺点。仿真结果表明,基于混沌差分进化算法拟配得到的等效系统满足等效系统拟配的各项要求和一级飞行品质的要求,取得了更好的拟配效果。证明该算法在飞机等效系统拟配中的有效性和高效性。
Abstract:
Chaotic differential evolution algorithm based on Tent map was introduced. Taking aircraft longitudinal short period system as an example,the analog-matching of the aircraft longitudinal equivalent system based on chaotic differential evolution algorithm was studied firstly and overcome the disadvantages of the conventional algorithms in the analog-matching of equivalent system. The simulation results show that the equivalent system by chaotic differential evolution algorithm is satisfied the various requirements in the analog-matching of equivalent system and the requirement of level 1 flight qualities,and has obtained better analog-matching results. The usefulness and high effectiveness of the chaotic differential evolution algorithm in the analog-matching of aircraft equivalent system is proved.  相似文献   
615.
The influences of a tidal cycle on the distribution of autotrophic plankton were investigated in a hyper-eutrophic lagoon designated as a scenic area. Results showed that the highest concentrations of picoplankton and phytoplankton were found in the middle and inner part of the lagoon, irrespective of the tides. The MDS result also revealed that phytoplankton communities, dominated by Ceratium furca, were similar among stations in the inner bay during both flood tides and ebb tides. The time series sampling results at the inlet-outlet channel revealed that almost the same amounts of phytoplankton and picoplankton were carried through the channel during flood and ebb tides, with no trend in nutrient fluctuations except for phosphate which had a net loss from the lagoon. The results showed that tidal cycles do not effectively flush away phytoplankton and picoplankton from the lagoon, and the blooming of phyto- and picoplankton is inevitable should the situation stay the same. Steps are needed to alleviate the eutrophication condition instead of depending on the natural process such as tidal cycle.  相似文献   
616.
根据朗伯-比耳定律和吸光度加和性,对RGB叶绿素仪采用透射光测量叶绿素含量方法进行分析,得到植物叶片叶绿素含量测量方程——多元线性回归方程.利用RGB叶绿素仪和商用叶绿素仪SPAD502对绿色程度不同的彩纸进行测试与对比,初步证明了该测量方法的有效性.选取2组黄瓜叶片,分别利用RGB叶绿素仪、SPAD502和分光光度计测量,得到RGB频率值、SPAD值和标准叶绿素含量值.取其中一组测量数据,对RGB频率值与标准叶绿素含量进行多元线性回归分析,获得测量模型的回归系数,再取另一组测量数据来验证所获得的测量模型回归系数的正确性;并将用RGB叶绿素仪和SPAD502仪测得数据做进一步的比较.结果验证:RGB叶绿素仪测量多元线性回归方程为极显著,所测叶绿素含量的重复性较SPAD502仪好.  相似文献   
617.
Theoretical and practical knowledge regarding low-mature gasses is of significant importance to identifying potential natural gas resources. Light hydrocarbon parameters and C and H isotopes are useful tools to identify low-mature gas. Twenty gas samples were collected from the Turpan-Hami Basin for light hydrocarbon analyses. The results showed that the light hydrocarbon components of natural gases contain high methylcycloxane, high isoparaffin and low benzene. This implies that the gas-generating parent materials are of typical humus type and the paleoenvironment is a fresh water sedimentary environment. These features are consistent with the geological setting of the basin. Comparative studies of isoheptane, heptane, and the carbon isotopic compositions of methane in natural gases, and other maturity indices indicated that natural gases in the Turpan-Hami Basin are dominated by low-mature gas formed during the low evolution stage of Jurassic coal seams. The parent materials are of type III, and the maturation degree was in the low evolution stage. These are the fundamental characteristics of low-mature gas. Results of light hydrocarbon research provided further evidence to suggest that the Turpan-Hami Basin is a large-scale gas producer of low-mature gas in China. It is likely that this resource will play an important role in future exploration and development of low-mature gas in China.  相似文献   
618.
Performance of fixed relays in orthogonal frequency division multiple access (OFDMA) systems, especially the coverage and capacity performance at the cell edge, is evaluated in this paper.Two methods, theoretical analysis and calculation and Monte Carlo simulation, are used for the evaluations.By theoretical analysis and calculation, frequency efficiency equation of a relay is introduced and numerical results are calculated.Monte Carlo simulation results also verify that the calculation method is reasonable.The evaluation shows that a relay can increase system performance to a certain level if it is designed appropriately, otherwise it will be harmful for the system performance, even to reduce it.  相似文献   
619.
根据新颁布的<防治船舶污染海洋环境管理条例>,要求建立船舶油污损害基金制度.主要比较一些航运大国的油污损害基金制度的不同运行模式,分析基金制度运行的优劣,为建立中国油污损害基金制度,提出建议.  相似文献   
620.
对多个电厂省煤器出口和SCR出口烟气中SO3浓度进行了测试,并对两个典型超低排放1000MW机组50%、75%和100%负荷烟气中SO3浓度进行了全流程现场实验,主要研究典型燃煤电站中三氧化硫的生成和全流程分布特性。结果表明,三氧化硫炉内生成率一般在0.145%-0.785%之间,SCR装置内SO3生成率为0.165-0.86%。空预器后SO3浓度降低,降低幅度为18.3-28.1%;传统静电除尘器和低低温静电除尘器对三氧化硫的脱除率分别9999为7.5-10%和20.2-31.4%。传统湿法脱硫装置和高效脱硫除尘一体化装置对SO3的脱除率分别为22.2-29.5%和26.2-36.7%。采用湿法脱硫+湿式静电除尘器的组合方式实现超低排放的燃煤电站对SO3的总脱除效率为61.2-76.4%,最终排放浓度为2.48-3.36mg/Nm3。采用高效脱硫除尘一体化装置的燃煤电站三氧化硫总脱除效率为59.3-62%,最终排放浓度为6.8-8.6mg/Nm3。  相似文献   
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