全文获取类型
收费全文 | 53881篇 |
免费 | 5091篇 |
国内免费 | 2492篇 |
专业分类
电工技术 | 3484篇 |
技术理论 | 4篇 |
综合类 | 6305篇 |
化学工业 | 4391篇 |
金属工艺 | 1146篇 |
机械仪表 | 2488篇 |
建筑科学 | 6216篇 |
矿业工程 | 2211篇 |
能源动力 | 1379篇 |
轻工业 | 5401篇 |
水利工程 | 2311篇 |
石油天然气 | 4400篇 |
武器工业 | 918篇 |
无线电 | 3122篇 |
一般工业技术 | 5094篇 |
冶金工业 | 1961篇 |
原子能技术 | 408篇 |
自动化技术 | 10225篇 |
出版年
2024年 | 231篇 |
2023年 | 722篇 |
2022年 | 1323篇 |
2021年 | 1644篇 |
2020年 | 1703篇 |
2019年 | 1473篇 |
2018年 | 1422篇 |
2017年 | 1603篇 |
2016年 | 1985篇 |
2015年 | 2066篇 |
2014年 | 3574篇 |
2013年 | 3272篇 |
2012年 | 4152篇 |
2011年 | 4459篇 |
2010年 | 3274篇 |
2009年 | 3370篇 |
2008年 | 2959篇 |
2007年 | 3569篇 |
2006年 | 3084篇 |
2005年 | 2683篇 |
2004年 | 2216篇 |
2003年 | 1884篇 |
2002年 | 1446篇 |
2001年 | 1212篇 |
2000年 | 956篇 |
1999年 | 854篇 |
1998年 | 666篇 |
1997年 | 606篇 |
1996年 | 471篇 |
1995年 | 432篇 |
1994年 | 314篇 |
1993年 | 263篇 |
1992年 | 180篇 |
1991年 | 157篇 |
1990年 | 126篇 |
1989年 | 151篇 |
1988年 | 108篇 |
1987年 | 74篇 |
1986年 | 70篇 |
1985年 | 79篇 |
1984年 | 99篇 |
1983年 | 116篇 |
1982年 | 105篇 |
1981年 | 42篇 |
1980年 | 34篇 |
1979年 | 31篇 |
1978年 | 28篇 |
1977年 | 25篇 |
1959年 | 12篇 |
1955年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Jan Rosell Carlos Vázquez Alexander Pérez Pedro Iñiguez 《Journal of Intelligent and Robotic Systems》2008,53(3):223-245
Haptic devices allow a user to feel either reaction forces from virtual interactions or reaction forces reflected from a remote
site during a bilateral teleoperation task. Also, guiding forces can be exerted to train the user in the performance of a
virtual task or to assist him/her to safely teleoperate a robot. The generation of guiding forces relies on the existence
of a motion plan that provides the direction to be followed to reach the goal from any free configuration of the configuration
space (-space). This paper proposes a method to obtain such a plan that interleaves a sampling-based exploration of -space with an efficient computation of harmonic functions. A deterministic sampling sequence (with a bias based on harmonic
function values) is used to obtain a hierarchical cell decomposition model of -space. A harmonic function is iteratively computed over the partially known model using a novel approach. The harmonic function
is the navigation function used as motion plan. The approach has been implemented in a planner (called the Kautham planner) that, given an initial and a goal configuration, provides: (a) a channel of cells connecting the cell that contains
the initial configuration with the cell that contains the goal configuration; (b) two harmonic functions over the whole -space, one that guides motions towards the channel and another that guides motions within the channel towards the goal; and
(c) a path computed over a roadmap built with the free samples of the channel. The harmonic functions and the solution path
are then used to generate the guiding forces for the haptic device. The planning approach is illustrated with examples on
2D and 3D workspaces.
This work was partially supported by the CICYT projects DPI2005-00112 and DPI2007-63665. 相似文献
992.
Dynamic memory allocation has been used for decades. However, it has seldom been used in real-time systems since the worst
case of spatial and temporal requirements for allocation and deallocation operations is either unbounded or bounded but with
a very large bound.
In this paper, a new allocator called TLSF (Two Level Segregated Fit) is presented. TLSF is designed and implemented to accommodate
real-time constraints. The proposed allocator exhibits time-bounded behaviour, O(1), and maintains a very good execution time. This paper describes in detail the data structures and functions provided by
TLSF. We also compare TLSF with a representative set of allocators regarding their temporal cost and fragmentation.
Although the paper is mainly focused on timing analysis, a brief study and comparative analysis of fragmentation incurred
by the allocators has been also included in order to provide a global view of the behaviour of the allocators.
The temporal and spatial results showed that TLSF is also a fast allocator and produces a fragmentation close to that caused
by the best existing allocators.
相似文献
Alfons Crespo (Corresponding author)Email: |
993.
Choosing knowledge management strategies by using a combined ANP and DEMATEL approach 总被引:4,自引:1,他引:3
Numerous companies are expecting their knowledge management (KM) to be performed effectively in order to leverage and transform the knowledge into competitive advantages. However, here raises a critical issue of how companies can better evaluate and select a favorable KM strategy prior to a successful KM implementation. The KM strategy selection is a kind of multiple criteria decision-making (MCDM) problem, which requires considering a large number of complex factors as multiple evaluation criteria. A robust MCDM method should consider the interactions among criteria. The analytic network process (ANP) is a relatively new MCDM method which can deal with all kinds of interactions systematically. Moreover, the Decision Making Trial and Evaluation Laboratory (DEMATEL) not only can convert the relations between cause and effect of criteria into a visual structural model, but also can be used as a way to handle the inner dependences within a set of criteria. Hence, this paper proposes an effective solution based on a combined ANP and DEMATEL approach to help companies that need to evaluate and select KM strategies. Additionally, an empirical study is presented to illustrate the application of the proposed method. 相似文献
994.
持续审计(CA)研究综述 总被引:4,自引:0,他引:4
持续审计(Continuous Auditing,CA)是目前计算机辅助审计领域中的一个研究前沿问题.本文对CA的研究进行了分析、比较和展望.首先分析了CA的内涵.然后,对CA的相关研究进行了分类:(1)技术实现方法,分成嵌入式和分离式两种;(2)理论分析;(3)应用于CA的关键技术,并根据该分类对CA的研究分别进行了分析.最后,总结了本文的工作,并对将来CA的研究做了展望. 相似文献
995.
本文针对目前高校计算机试验课教学的特点和现状,从试验教学的内容和形式方法上进行了探讨,同时提出了关于《数据库技术》试验课教学的改革方法。 相似文献
996.
许礼捷 《数字社区&智能家居》2009,(2)
介绍了入侵检测技术中的两种聚类算法,阐述算法在入侵检测技术中的应用原理,并针对算法的优缺点提出改进的算法,通过分析表明,改进算法是一种较为理想的算法。 相似文献
997.
针对虚拟化环境下图形显示的特点,该文充分考虑了在虚拟化环境下显示性能的特殊性,选取了六个不同的应用,将其作为评价虚拟化环境下显示性能的重要指标;与此同时提出了一个虚拟化环境下虚拟机显示性能的评价标准,作为判断虚拟环境下虚拟机显示性能好坏的依据。 相似文献
998.
介绍了工程数学中的模糊综合评判理论以及相应树型向量推理算法,并将模糊综合推理机制运用到研究性学习系统中进行研究型应用。该系统中运用模糊综合评判对学习效果进行合理评判,得出综合成绩,以其作为改进研究性学习模式的参考评证,从而使研究性学习过程良性发展。 相似文献
999.
创建选区是Photoshop中最基本,也是最重要的技法之一。该文归纳了Photoshop中选区的多种方法和思路,阐明了各种方法的优势和特点,探讨如何综合运用各种工具和命令,充分发挥各工具特点,从而快速精确的建立选区。 相似文献
1000.
对文本特征选择的传统方法进行了深入分析并对各自的优缺点进行了详细的对比;其次,通过利用遗传算法自身的寻优特点,把它与传统特征选择方法相结合,并得出了算法。最后,在对各自算法进行了分析,表明了在性能上有了明显的提高。 相似文献