全文获取类型
收费全文 | 2173篇 |
免费 | 246篇 |
国内免费 | 192篇 |
专业分类
电工技术 | 101篇 |
综合类 | 224篇 |
化学工业 | 35篇 |
金属工艺 | 49篇 |
机械仪表 | 139篇 |
建筑科学 | 127篇 |
矿业工程 | 34篇 |
能源动力 | 23篇 |
轻工业 | 16篇 |
水利工程 | 25篇 |
石油天然气 | 17篇 |
武器工业 | 14篇 |
无线电 | 303篇 |
一般工业技术 | 159篇 |
冶金工业 | 88篇 |
原子能技术 | 9篇 |
自动化技术 | 1248篇 |
出版年
2024年 | 3篇 |
2023年 | 23篇 |
2022年 | 30篇 |
2021年 | 30篇 |
2020年 | 44篇 |
2019年 | 46篇 |
2018年 | 39篇 |
2017年 | 49篇 |
2016年 | 70篇 |
2015年 | 72篇 |
2014年 | 138篇 |
2013年 | 113篇 |
2012年 | 123篇 |
2011年 | 155篇 |
2010年 | 137篇 |
2009年 | 144篇 |
2008年 | 161篇 |
2007年 | 181篇 |
2006年 | 176篇 |
2005年 | 145篇 |
2004年 | 106篇 |
2003年 | 113篇 |
2002年 | 91篇 |
2001年 | 73篇 |
2000年 | 70篇 |
1999年 | 35篇 |
1998年 | 41篇 |
1997年 | 28篇 |
1996年 | 36篇 |
1995年 | 32篇 |
1994年 | 23篇 |
1993年 | 22篇 |
1992年 | 10篇 |
1991年 | 13篇 |
1990年 | 5篇 |
1989年 | 8篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1977年 | 2篇 |
1962年 | 1篇 |
1961年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有2611条查询结果,搜索用时 0 毫秒
71.
张三元 《中国图象图形学报》2001,6(6):573-576
曲面上的曲线造型是计算机图形领域的一个新的研究热点,而且它们在纤维织物编织,三维服装裁剪以及复合材料的纤维缠绕轨迹设计等领域有十分广泛的应用,为了解决圆环面上纤维轨迹的计算机辅助设计问题,研究了圆环面上测地线的解析解以及拟测地线数值求解的具体算法并给出了其表达式,测地线是曲面上两点之间最短距离的曲线段,在一般曲面上没有解析解,但是在圆环面上却可求出其精确的解析解,但在曲面的边沿部分,测地线因不能实现自然的折返过渡,于是拟测地线就被引进到曲面上的曲线造型设计之中,在拟测地线分析研究基础上,给出了圆环面上拟测地线的方程及数值解法,通过其在一个实例中的应用结果证明,该方法可获得织物的纺织条纹以及缠绕物体的纤维轨迹。 相似文献
72.
Yufei Tao Xiaokui Xiao 《The VLDB Journal The International Journal on Very Large Data Bases》2008,17(5):1253-1270
The existing predictive spatiotemporal indexes can be classified into two categories, depending on whether they are based
on the primal or dual methodology. Although we have gained considerable empirical knowledge about various access methods, currently there is only
limited understanding on the theoretical characteristics of the two methodologies. In fact, the experimental results in different
papers even contradict each other, regarding the relative superiority of the primal and dual techniques. This paper presents
a careful study on the query performance of general primal and dual indexes, and reveals important insight into the behavior
of each technique. In particular, we mathematically establish the conditions that determine the superiority of each methodology,
and provide rigorous justification for well-known observations that have not been properly explained in the literature. Our
analytical findings also resolve the contradiction in the experiments of previous work. 相似文献
73.
Dong-Suk Hong Hong-Koo Kang Dong-Oh Kim Jae-Kwan Yun Ki-Joon Han 《The Journal of supercomputing》2007,42(3):321-337
There is rapidly increasing interest in Location Based Service (LBS) which utilizes location data of moving objects. To efficiently
manage the huge amounts of location data in LBS, the GALIS (Gracefully Aging Location Information System) architecture, a
cluster-based distributed computing architecture, is proposed. The GALIS using the non-uniform 2-level grid algorithm performs
load balancing and indexing for nodes. However, the non-uniform 2-level grid algorithm has a problem creating unnecessary
nodes when moving objects are crowded in a certain region. Therefore, a new node split algorithm, which is more efficient
for various distribution of moving objects, is proposed in this paper. Because the algorithm proposed in this paper considers
spatial distribution for the current location of moving objects, it can perform efficient load balancing without creating
unnecessary nodes even when moving objects are congested in a certain region. Besides, the various data distribution configuration
for moving objects has been experimented by implementing node split simulators and it’s been verified that the proposed algorithm
can split nodes more efficiently than the existing algorithm.
相似文献
Ki-Joon Han (Corresponding author)Email: |
74.
This paper introduces an accurate, efficient, and unified engine dedicated to dynamic animation of d-dimensional deformable objects. The objects are modelled as d-dimensional manifolds defined as functional combinations of a mesh of 3D control points, weighted by parametric blending
functions. This model ensures that, at each time step, the object shape conforms to its manifold definitions. The object motion
is deduced from the control points dynamic animation. In fact, control points should be viewed as the degrees of freedom of
the continuous object. The chosen dynamic equations (Lagrangian formalism) reflect this generic modelling scheme and yield
an exact and computationally efficient linear system. 相似文献
75.
水利信息化是实现水利现代化的基础和重要标志。以水管理对象为基础,利用现代信息技术构造数字流域,集中管理流域内的水事问题,是实现流域现代化管理的有效途径。从数字流域体系架构、水管理对象构造及全息化描述、基础平台构建、业务系统的构件化开发、数字功能流域等方面详细介绍了基于水管理对象的数字流域构造技术方法。 相似文献
76.
P. Jiménez 《Robotics and Computer》2012,28(2):154-163
A systematic overview on the subject of model-based manipulation planning of deformable objects is presented. Existing modeling techniques of volumetric, planar and linear deformable objects are described, emphasizing the different types of deformation. Planning strategies are categorized according to the type of manipulation goal: path planning, folding/unfolding, topology modifications and assembly. Most current contributions fit naturally into these categories, and thus the presented algorithms constitute an adequate basis for future developments. 相似文献
77.
Question–answering systems make good use of knowledge bases (KBs, e.g., Wikipedia) for responding to definition queries. Typically, systems extract relevant facts from articles regarding the question across KBs, and then they are projected into the candidate answers. However, studies have shown that the performance of this kind of method suddenly drops, whenever KBs supply narrow coverage. This work describes a new approach to deal with this problem by constructing context models for scoring candidate answers, which are, more precisely, statistical n‐gram language models inferred from lexicalized dependency paths extracted from Wikipedia abstracts. Unlike state‐of‐the‐art approaches, context models are created by capturing the semantics of candidate answers (e.g., “novel,”“singer,”“coach,” and “city”). This work is extended by investigating the impact on context models of extra linguistic knowledge such as part‐of‐speech tagging and named‐entity recognition. Results showed the effectiveness of context models as n‐gram lexicalized dependency paths and promising context indicators for the presence of definitions in natural language texts. 相似文献
78.
《国际计算机数学杂志》2012,89(1-4):75-110
This paper describes the analysis of networks, using digital computers. If the nodes of the network are assigned alpha-numeric symbols, the network is said to be alpha-numerical. The paper describes transforma-tions of non-directed alpha-numeric networks: edges are separated and rearranged so as to form new networks. The results of these investiga-tions lead to the formulation of algorithms, which have been programmed and solved on a ZUSEZ 22 digital computer. Networks are stored as incidence matrices and transformed by matrix operations. Transforma-tions which are effected by separation and rejoining of at most two edges, are called elementary transformations. It will be shown that every struc-tural transformation can be represented as a logical consequence of elementary transformations. Our investigations permit the following ex-positions: Alpha-numerical networks can be interpreted as chemical structure formulae; transformations can be interpreted as chemical reactions. 相似文献
79.
《国际计算机数学杂志》2012,89(3):289-300
Multi-objective shortest path problem (MOSPP) is an active area of research because of its application in a large number of systems such as transportation systems, communication systems, power transmission systems, pipeline distribution systems of water, gas, blood and drainage, neural decision systems, production planning and project planning. In these networks it becomes necessary to find the best path from one node to a specified or all other nodes. The computational complexity of the existing algorithms in the literature to compute all Pareto minimum paths from a specified source node to all other nodes in an MOSPP is of exponential order in the worst case. Instead of generating all the values of the Pareto minimum paths in exponential time, we propose an algorithm to find a set of values of the Pareto minimum paths in polynomial time, which is very significant in many contexts. If an MOSPP of a network is having negative cycle, all the existing algorithm only indicate the existence of the negative cycle, that too after exponential number of operations. However, applying the proposed algorithm, we can find a set of Pareto minimum paths of any MOSPP of a network even if it contains negative cycles. The proposed algorithm is illustrated with examples. 相似文献
80.