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991.
当前因受“狭议工具论”错误认识的影响致使非计算机专业大学计算机基础教育受到冲击,计算机基础课程的学时也被缩减.针对这一问题,提出了以计算思维培养为核心,“技能-能力-计算思维”三层次培养目标的教学改革.对课程内容进行了面向知识能力、计算思维教学的内容重构与组织,给出了具体的教学内容模块,同时探讨了计算思维培养教学方法. 相似文献
992.
Z.W. Yin Author vitae 《Computer aided design》2011,(6):699-706
An extended STL file format is presented in this paper. Differing with existing solutions, it proposes a new format to produce and store triangles. The format uses a cluster unit composed of several triangles. The main advantages of the format are that it contains both geometry and topological information and has improved storage capability. Direct generation of the extended STL from the scanned data has a great advantage in that it can reduce the time and error in modeling process. In order to obtain the format from unorganized point cloud, a new triangulation algorithm was introduced. The algorithm is based on reconstructing the relative Delaunay triangulation of the sample points on the surface. Other advantages of the extended STL format were also presented in this paper. 相似文献
993.
Liu A Nickerson A Troyer A Yin X Cary R Thornburg K Wang R Rugonyi S 《Computers & Structures》2011,89(11-12):855-867
Wall shear stresses (WSS) exerted by blood flow on cardiac tissues modulate growth and development of the heart. To study the role of hemodynamic conditions on cardiac morphogenesis, here, we present a methodology that combines imaging and finite element modeling to quantify the in vivo blood flow dynamics and WSS in the cardiac outflow tract (OFT) of early chicken embryos (day 3 out of 21-day incubation period). We found a distinct blood flow field and heterogeneous distribution of WSS in the chicken embryonic heart OFT, which have physiological implications for OFT morphogenesis. 相似文献
994.
We present an effective optimization framework to compute polycube mapping. Composed of a set of small cubes, a polycube well approximates the geometry of the free-form model yet possesses great regularity; therefore, it can serve as a nice parametric domain for free-form shape modeling and analysis. Generally, the more cubes are used to construct the polycube, the better the shape can be approximated and parameterized with less distortion. However, corner points of a polycube domain are singularities of this parametric representation, so a polycube domain having too many corners is undesirable. We develop an iterative algorithm to seek for the optimal polycube domain and mapping, with the constraint on using a restricted number of cubes (therefore restricted number of corner points). We also use our polycube mapping framework to compute an optimal common polycube domain for multiple objects simultaneously for lowly distorted consistent parameterization. 相似文献
995.
Yin P Criminisi A Winn J Essa I 《IEEE transactions on pattern analysis and machine intelligence》2011,33(1):30-42
This paper presents an automatic segmentation algorithm for video frames captured by a (monocular) webcam that closely approximates depth segmentation from a stereo camera. The frames are segmented into foreground and background layers that comprise a subject (participant) and other objects and individuals. The algorithm produces correct segmentations even in the presence of large background motion with a nearly stationary foreground. This research makes three key contributions: First, we introduce a novel motion representation, referred to as "motons," inspired by research in object recognition. Second, we propose estimating the segmentation likelihood from the spatial context of motion. The estimation is efficiently learned by random forests. Third, we introduce a general taxonomy of tree-based classifiers that facilitates both theoretical and experimental comparisons of several known classification algorithms and generates new ones. In our bilayer segmentation algorithm, diverse visual cues such as motion, motion context, color, contrast, and spatial priors are fused by means of a conditional random field (CRF) model. Segmentation is then achieved by binary min-cut. Experiments on many sequences of our videochat application demonstrate that our algorithm, which requires no initialization, is effective in a variety of scenes, and the segmentation results are comparable to those obtained by stereo systems. 相似文献
996.
Yuan-sheng Luo Yong Qi Di HouLin-feng Shen Ying ChenXiao Zhong 《Computer Communications》2011,34(9):1137-1144
Many works have been carried out to find the efficient algorithms for QoS-aware service composition in recent years. Nevertheless, on one hand, some of these works only consider the local QoS attributes in Web services composition; on the other hand, some ideas derived from QoS selection algorithms for network routing are directly applied in service composition without any adaption. A service composition model with end-to-end QoS constraints has been presented in this paper. An improved heuristics HCE based on the observation of characteristic of end-to-end service composition is proposed as a novel solution. Simulation results reveal the better performance of proposed heuristic compared to the other two heuristics, HMCOP and generic CE algorithm. 相似文献
997.
Tianjia Shao Weiwei Xu Kangkang Yin Jingdong Wang Kun Zhou Baining Guo 《Computer Graphics Forum》2011,30(7):2011-2020
We propose a sketch‐based 3D shape retrieval system that is substantially more discriminative and robust than existing systems, especially for complex models. The power of our system comes from a combination of a contour‐based 2D shape representation and a robust sampling‐based shape matching scheme. They are defined over discriminative local features and applicable for partial sketches; robust to noise and distortions in hand drawings; and consistent when strokes are added progressively. Our robust shape matching, however, requires dense sampling and registration and incurs a high computational cost. We thus devise critical acceleration methods to achieve interactive performance: precomputing kNN graphs that record transformations between neighboring contour images and enable fast online shape alignment; pruning sampling and shape registration strategically and hierarchically; and parallelizing shape matching on multi‐core platforms or GPUs. We demonstrate the effectiveness of our system through various experiments, comparisons, and user studies. 相似文献
998.
Yi Zeng Ning Zhong Yan Wang Yulin Qin Zhisheng Huang Haiyan Zhou Yiyu Yao Frank van Harmelen 《Knowledge and Information Systems》2011,27(3):419-450
Under the context of large-scale scientific literatures, this paper provides a user-centric approach for refining and processing
incomplete or vague query based on cognitive- and granularity-based strategies. From the viewpoints of user interests retention
and granular information processing, we examine various strategies for user-centric unification of search and reasoning. Inspired
by the basic level for human problem-solving in cognitive science, we refine a query based on retained user interests. We
bring the multi-level, multi-perspective strategies from human problem-solving to large-scale search and reasoning. The power/exponential
law-based interests retention modeling, network statistics–based data selection, and ontology-supervised hierarchical reasoning
are developed to implement these strategies. As an illustration, we investigate some case studies based on a large-scale scientific
literature dataset, DBLP. The experimental results show that the proposed strategies are potentially effective. 相似文献
999.
1000.