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1.
教材分析是连接教材和课程的桥梁,基于宏观辨识和微观探析核心素养,比较分析了2004年版和2019年版高中《化学1(必修)》教材的特点。通过运用“三序结合”原则,从静态视角对比教材栏目设置、内容组织形式、核心素养呈现方式、学生认知水平以及作业布置形式等5个维度要素在宏微辨析核心素养领域的建构。分析结果显示,2019年版《化学1(必修)》教材在以上要素方面均围绕宏微辨析核心素养,呈现不同水平阶梯型设置。建议在“宏微符”概念形成的过程中增设更为细致的过渡内容,以及更为详尽的与教材配套的辅助内容,便于教材的二次开发。 相似文献
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Egor A. Kapitonov Natalia N. Petrova Vasilii V. Mukhin Leonid A. Nikiforov Vladimir D. Gogolev Ee Le Shim Aitalina A. Okhlopkova Jin-Ho Cho 《Molecules (Basel, Switzerland)》2021,26(4)
The physical and mechanical properties of nitrile–butadiene rubber (NBR) composites with N-cetylpyridinium bromide-carbon black (CPB-CB) were investigated. Addition of 5 parts per hundred rubber (phr) of CPB-CB into NBR improved the tensile strength by 124%, vulcanization rate by 41%, shore hardness by 15%, and decreased the volumetric wear by 7% compared to those of the base rubber-CB composite. 相似文献
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In the present work, a further numerical simulation of the starting flow around a flat plate normal to the direction of motion
in a uniform fluid has been made by means of the discrete vortex method. The secondary separation occurring at rear surface
of the plate is explored, and predicted approximately using Thwait's method. The calculated results show that in the early
stages of the flow secondary separation does occur. The evolution of flow field, the vortex growing process and the characteristics
of secondary vortices have been described. The time dependent drag coefficients, the vorticity shed from the edges and rear
surface, and the separation positions are calculated as well as the distributions of velocity and pressure on the plate. In
the case of flow normal to the plate, the calculated secondary vortices are weak. Their existence will change the local velocity
distributions and affect pressure distributions. However, the effect on drag coefficient is negligible. 相似文献
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Shawn Mankad George Michailidis 《Journal of computational and graphical statistics》2013,22(4):943-965
Three-dimensional data arrays (collections of individual data matrices) are increasingly prevalent in modern data and pose unique challenges to pattern extraction and visualization. This article introduces a biclustering technique for exploration and pattern detection in such complex structured data. The proposed framework couples the popular plaid model together with tools from functional data analysis to guide the estimation of bicluster responses over the array. We present an efficient algorithm that first detects biclusters that exhibit strong deviations for some data matrices, and then estimates their responses over the entire data array. Altogether, the framework is useful to home in on and display underlying structure and its evolution over conditions/time. The methods are scalable to large datasets, and can accommodate a variety of dynamic patterns. The proposed techniques are illustrated on gene expression data and bilateral trade networks. Supplementary materials are available online. 相似文献
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Probability theory has become the standard framework in the field of mobile robotics because of the inherent uncertainty associated with sensing and acting. In this paper, we show that the theory of belief functions with its ability to distinguish between different types of uncertainty is able to provide significant advantages over probabilistic approaches in the context of robotics. We do so by presenting solutions to the essential problems of simultaneous localization and mapping (SLAM) and planning based on belief functions. For SLAM, we show how the joint belief function over the map and the robot's poses can be factored and efficiently approximated using a Rao-Blackwellized particle filter, resulting in a generalization of the popular probabilistic FastSLAM algorithm. Our SLAM algorithm produces occupancy grid maps where belief functions explicitly represent additional information about missing and conflicting measurements compared to probabilistic grid maps. The basis for this SLAM algorithm are forward and inverse sensor models, and we present general evidential models for range sensors like sonar and laser scanners. Using the generated evidential grid maps, we show how optimal decisions can be made for path planning and active exploration. To demonstrate the effectiveness of our evidential approach, we apply it to two real-world datasets where a mobile robot has to explore unknown environments and solve different planning problems. Finally, we provide a quantitative evaluation and show that the evidential approach outperforms a probabilistic one both in terms of map quality and navigation performance. 相似文献
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The Transition Rapidly exploring Random Eigenvector Assisted Tree (TRREAT) algorithm is introduced to perform searches along low curvature pathways on a potential energy surface (PES). The method combines local curvature information about the PES with an iterative Rapidly exploring Random Tree algorithm (LaValle, Computer Science Department, Iowa State University, 1998, TR98–11) that quickly searches high‐dimensional spaces for feasible pathways between local minima. Herein, the method is applied to identifying conformational changes of molecular systems using Cartesian coordinates while avoiding a priori definition of collective variables. We analyze the pathway identification problem for alanine dipeptide, cyclohexane and glycine using nonreactive and reactive forcefields. We show how TRREAT‐identified pathways can be used as valuable input guesses for double‐ended methods such as the Nudged Elastic Band when ascertaining transition state energies. This method can be utilized to improve/extend the reaction databases that lie at the core of automatic chemical reaction mechanism generator software currently developed to build kinetic models of chemical reactions. © 2013 Wiley Periodicals, Inc. 相似文献