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841.
当前对肥胖儿童间歇性周期运动下的心肺耐力反应建模分析方法,一般是在运动形式保持不变的情况下,搭建二维动态建模,无法准确给出间歇性周期运动对肥胖儿童的重要性,建模分析准确性较低,且有效性与实用性差。因此,提出准确性和有效性较高的肥胖儿童间歇性周期运动下的心肺耐力反应三维建模分析方法,利用该方法,在不同运动形式的情况下,对肥胖儿童间歇性周期运动下的心率、肺活量指数和最大摄氧量进行三维动态建模,给出三维动态建模分析式,确定间歇性周期运动对肥胖儿童心肺健康的重要性。实验通过对比分析方式,证明所提方法拥有较高的建模分析准确性和有效性。  相似文献   
842.
We consider in this paper interpolation problems for weighted spaces of entire and meromorphic functions. Various (analytic and geometric) conditions necessary and sufficient for multiplicity varieties to be interpolating varieties will be given. This research is supported in part by NSF Grants DMS-90-00616 and CDR 88-03012.  相似文献   
843.
One of the methods of industrial dimethyl ether production is the catalytic dehydration of methanol. In this research work, methanol dehydration reactor has been modeled using continuous model and its results have been compared with experimental works and Voronoi pore network model. A 1D heterogeneous dispersed plug flow model was utilized to model an adiabatic fixed-bed reactor for the catalytic dehydration of methanol to dimethyl ether. The mass and heat transfer equations are numerically solved for the reactor. The concentration of the reactant and products and also the temperature varies along the reactor, therefore the effectiveness factor would also change in the reactor. We used the the effectiveness factor that was simulated according to the diffusion and reaction in the catalyst pellet as a Voronoi pore network model. Sensitivity analysis was performed to determine the influence of T, P and weight hourly space velocity on performance of the chemical reactor. Acceptable agreement was reached between the measured and the model data. The results showed that the maximum reaction conversion was obtained about 90 % at WHSV = 10 h?1 and T = 560 K, while the inlet temperature (Tinlet) had a greater effect on methanol conversion. In addition, the effect of water in the feed on methanol conversion was quantitatively studied. Also, the deactivation kinetics of γ-Al2O3 heterogeneous-acidic catalyst in methanol to dimethyl ether dehydration process was studied using integral analysis method. Based on independent deactivation kinetics, a second order was found that accurately fitted the experimental conversion time data. The main reaction activation energies and catalyst deactivation energies were 143.1 and ?102.1 kJ/mol, respectively.  相似文献   
844.
基于UML的学生管理系统设计   总被引:2,自引:0,他引:2  
采用统一建模语言UML,对学生信息管理系统的结构关系建模,阐述了UML在系统 中的可视化建模机制,从不同的层面给出了系统的需求分析及系统设计的整个过程,规范和 扩充了系统的数据,增强了系统交互性.  相似文献   
845.
针对火电厂的安全评价问题,通过分析SDG的建模特点和研究HAZOP分析技术,提出了基于层次SDG-HAZOP的安全评价建模方法,并将其应用于火电厂的安全评价建模。该方法利用AHP的递阶层次结构对火电厂生产设备进行模块的分层,应用实例表明,AHP的递阶层次结构简化了建模的复杂度。SDG-HAZOP所建模型的完备性好,且通过SDG-HAZOP推理策略得到的结果能够全面反映火电厂可能存在的危险,并能揭示危险传播的路径。本方法也可以适用于其它过程工业的安全评价。  相似文献   
846.
以球杆系统为研究对象,设计了一种横杆单端铰接的球杆系统。该系统通过旋转电位计设定小球在横杆上理想位置,通过高频近距离激光位移传感器检测小球的实际位置,由单片机内部的PID算法控制输入到滚珠丝杠电机驱动器的PWM输出频率,使滚珠丝杠电机正、反转,从而实现小球停在设定理想位置。在Matlab/Simulink中进行建模仿真对影响系统稳定性的不同敏感因素进行研究。结果表明小球初始位置、滑动摩擦对系统稳定性产生影响。  相似文献   
847.
A quantitative structure property relationship (QSPR) is proposed to calculate the electrophoretic mobility of analytes in capillary zone electrophoresis. The proposed model employs logarithm of the electrophoretic mobility (ln micro) as dependent variable and partial charge (PQ), surface area (V(2/3)), total energy (TE), heat of formation (DeltaH(f)) and molecular refractivity (MR) as independent variables whose calculated using AM1 (Austin model 1) semi-empirical quantum mechanics method by HyperChem 7.0 software. The general form of the model is: ln micro =K(0)+K(1)PQ+K(2)V(2/3)+K(3)TE+K(4)DeltaH(f)+K(5)MR, where K(0)-K(5) are the model constants computed using a least-square method. The applicability of the model on real mobility data has been studied employing five experimental data sets of beta-blockers, benzoate derivatives, non-steroidal anti-inflammatory drugs, sulfonamides and amines in different buffers. The accuracy of the model is assessed using absolute average relative deviation (AARD) and the overall AARD value. The obtained AARD for the sets studied are 1.0 (N=10), 2.1 (N=26), 0.8 (N=11), 0.6 (N=13) and 2.7% (N=18), respectively, and the overall AARD is 1.4%. The model is cross-validated using one leave out technique and the obtained overall AARD is 1.8%. To further investigate on the applicability of the proposed model, the prediction capability of the model is evaluated by employing a minimum number of six experimental data points as training set, and predicting the mobility of other data points using trained models. The obtained overall AARD (for 48 predicted data points) is 5.6%.  相似文献   
848.
基于近红外光谱的玉米籽粒CNCPS组分分析及预测研究   总被引:2,自引:0,他引:2  
试验旨在研究应用近红外光谱技术快速测定玉米籽粒粉末CNCPS组分的可行性。65个样品来自黑龙江省,选用偏最小二乘法(PLS)为建模方法,采用二阶导数和Norris导数滤波法处理光谱数据后,建立了玉米籽粒粉末中干物质(DM)、粗蛋白质(CP)、粗脂肪(Fat)、粗灰分(Ash)、淀粉(Starch)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、可溶性蛋白(SP)、酸性洗涤不溶蛋白(ADIP)和中性洗涤不溶蛋白(NDIP)等的近红外预测模型。其中DM,CP,Fat,Ash,Starch,NDF和ADF的决定系数分别为0.974 3,0.968 3,0.947 8,0.909 8,0.977 7,0.935 4和0.926 9,标准差(SD)与预测均方根(RMSEP)的比值(SD/RMSEP)值分别为3.96,4.78,3.75,4.25,4.13,3.88和3.12。SP的决定系数为0.857 5,SD/RMSEP值为3.06。ADIP和NDIP的决定系数分别为0.531 9和0.683 3,SD/RMSEP值分别为5.50和2.85。试验结果表明,近红外技术可以用于玉米籽粒粉末CNCPS组分的快速测定,但降低ADIP和NDIP测定误差有待进一步研究。  相似文献   
849.
Ted M. Knowlton   《Particuology》2010,8(6):501-502
Scaling laws based on the concept of dimensional similitude are proposed to simulate the hydrodynamics of hot and large particle systems at conditions of cold and small particle systems. This technique uses the concept of dimensional similitude to accomplish this by maintaining certain dimensional groups constant in the large, hot and small, cold systems. However, there are certain limitations with this technique. One of them is that the particle size in the small, cold system is usually smaller than in the large, hot system. Because particle size is such a dominant parameter in fluidized systems, this can certainly affect the simulation.
An alternative method of simulating hot hydrodynamics in ambient-temperature Group A particle systems has been proposed. In this method, the same calculated drag force is maintained between the two systems. The drag force is varied by changing the gas density of the cold system so that it matches the drag force in the hot system.  相似文献   
850.
Burken's “donut ring” model was solved correctly, which was developed based upon the anatomy structure and the flow patterns of the tree. The correction of the model solution was validated by our field experimental data statistically. The vertical PAHs in sapwood is described as a carbon–nitrogen–water interaction process, which is companied with the allocation of photosynthate and other non-structure carbon. It could be found that the vertical translocation is related to the height of the sampling position closely. The anisotropy result of the estimated Dz and Dr is in agreement with the structure of trunk tissue, suggesting that the radial diffusion is much difficult. Although the estimated Dz and Dr are confirmed to depend upon Kow (the partition coefficient of PAHs in octanol/water), the different dominant factors are demonstrated in our result. Although the metabolism and degradation in Burken's model were neglected, the evidence of degradation presents in this work. 2-Chloro-Nap might be the degradation product of Nap by adding Cl to Nap rings, for 2-chloro-Nap only contains in trunk samples. This result was validated by the first-order degradation equation. The initial degradation reaction mechanism was also discussed briefly.  相似文献   
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