全文获取类型
收费全文 | 2514篇 |
免费 | 109篇 |
国内免费 | 43篇 |
专业分类
电工技术 | 21篇 |
综合类 | 161篇 |
化学工业 | 74篇 |
金属工艺 | 34篇 |
机械仪表 | 35篇 |
建筑科学 | 511篇 |
矿业工程 | 11篇 |
能源动力 | 22篇 |
轻工业 | 43篇 |
水利工程 | 12篇 |
石油天然气 | 22篇 |
武器工业 | 4篇 |
无线电 | 92篇 |
一般工业技术 | 119篇 |
冶金工业 | 132篇 |
原子能技术 | 2篇 |
自动化技术 | 1371篇 |
出版年
2024年 | 7篇 |
2023年 | 31篇 |
2022年 | 14篇 |
2021年 | 34篇 |
2020年 | 46篇 |
2019年 | 90篇 |
2018年 | 53篇 |
2017年 | 46篇 |
2016年 | 95篇 |
2015年 | 138篇 |
2014年 | 145篇 |
2013年 | 144篇 |
2012年 | 193篇 |
2011年 | 202篇 |
2010年 | 179篇 |
2009年 | 180篇 |
2008年 | 159篇 |
2007年 | 176篇 |
2006年 | 88篇 |
2005年 | 91篇 |
2004年 | 68篇 |
2003年 | 88篇 |
2002年 | 69篇 |
2001年 | 48篇 |
2000年 | 47篇 |
1999年 | 31篇 |
1998年 | 26篇 |
1997年 | 25篇 |
1996年 | 19篇 |
1995年 | 12篇 |
1994年 | 6篇 |
1993年 | 13篇 |
1992年 | 8篇 |
1991年 | 10篇 |
1990年 | 16篇 |
1989年 | 8篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 9篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 6篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1975年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有2666条查询结果,搜索用时 15 毫秒
101.
Ivan Marsa-Maestre Miguel A. Lopez-Carmona Juan R. Velasco 《Service Oriented Computing and Applications》2008,2(4):167-185
Service Oriented Architectures, which allow for the integration of different subsystems and of applications running on different
devices and platforms, may be very suitable to solve the problem of service personalization in large smart environments like
cities, where the number of potential users and potentially available services is rapidly growing. Taking this into account,
we have designed an agent-based service oriented architecture for smart spaces. Two of the greatest challenges in the design
of such a solution are providing effective device, service and context federation and composition mechanisms and handling
user mobility. For the first challenge, we have designed a hierarchical architecture and developed a set of inheritance, aggregation
and access mechanisms for devices, services and context. To handle user mobility, we have followed three different strategies,
using stationary, mobile or nomadic agents. In this paper, we describe the main aspects of our architecture and perform an experimental evaluation to determine
the advantages and drawbacks of the different strategies. 相似文献
102.
Abstract Recent research has shown that students' use of information and communications technology (ICT) on teaching practice is necessary for effective future use of ICT in the classroom. However, this paper reports that there are a number of factors affecting the use of ICT by student-teachers in their school placements. All 110 student-teachers attending one university's eight Postgraduate Certificate in Education (PGCE) courses completed a questionnaire on their attitudes to ICT in learning and teaching and their initial experiences of the application of ICT in schools. In-depth interviews with the student-teachers, as well as univer-sity tutors and teachers, revealed a range of issues that reflected how student-teachers perceive their school-based ICT training and what they think could improve their experiences. Recommendations are offered for the improvement of the ICT school experiences for student-teachers until teacher training is completed and improved ICT infrastructure is in place in schools. The overriding conclusion is that schools must be supported and resourced properly, and teachers must have effective ICT training, before improvements in school-based ICT development for student-teachers can be achieved. 相似文献
103.
Evolutionary Learning of a Fuzzy Behavior Based Controller for a Nonholonomic Mobile Robot in a Class of Dynamic Environments 总被引:1,自引:0,他引:1
D. P. Thrishantha Nanayakkara Keigo Watanabe Kazuo Kiguchi Kiyotaka Izumi 《Journal of Intelligent and Robotic Systems》2001,32(3):255-277
This paper presents an approach for evolving optimum behaviors for a nonholonomic mobile robot in a class of dynamic environments. A new evolutionary algorithm reflecting some powerful features in the natural evolutionary process to have flexibility to deal with changes in the environment is used to evolve optimum behaviors. Furthermore, a fuzzy set based multi-objective fitness evaluation function is adopted in the evolutionary algorithm. The multi-objective evaluation function is designed so that it allows incorporating complex linguistic features that a human observer would desire in the behaviors of the mobile robot movements. To illustrate the effectiveness of the proposed method, simulation results are compared using a conventional evolutionary algorithm. 相似文献
104.
自主探测系统的Bayes递推估计策略 总被引:1,自引:0,他引:1
探测系统被动地接爱外界的测量信息是不够的,因此方式获得的数据是不完备的,由此揄得出的结论在一定程度上具有不确定性,是不能接受的,为获得可靠的信息,常采用多传感器的数据融合或装备自主传感器的方法,文中将Bayes递推估计策略应用于自主探测系统,使其能最逼真的再再所关心的探测对象。 相似文献
105.
Lina Peng K. Selçuk Candan Christopher Mayer Karamvir S. Chatha Kyung Dong Ryu 《Multimedia Tools and Applications》2007,33(3):245-272
In this paper, we present the ARIA media processing workflow architecture that processes, filters, and fuses sensory inputs
and actuates responses in real-time. The components of the architecture are programmable and adaptable; i.e. the delay, size,
and quality/precision characteristics of the individual operators can be controlled via a number of parameters. Each data
object processed by qStream components is subject to transformations based on the parameter values. For instance, the quality of an output data object
and the corresponding processing delay and resource usage depend on the values assigned to parameters of the operators in
the object flow path. In Candan, Peng, Ryu, Chatha, Mayer (Efficient stream routing in quality- and resource-adaptive flow
architectures. In: Workshop on multimedia information systems, 2004), we introduced a class of flow optimization problems that promote creation and delivery of small delay or small resource-usage objects to the actuators in single-sensor, single-actuator
workflows. In this paper, we extend our attention to multi-sensor media processing workflow scenarios. The algorithms we present
take into account the implicit dependencies between various system parameters, such as resource consumption and object sizes.
We experimentally show the effectiveness and efficiency of the algorithms.
相似文献
Kyung Dong RyuEmail: |
106.
The purpose of the study was to examine whether school furniture dimensions match children's anthropometry. Children aged 6-18 years (n=274), divided into 3 groups on the basis of the used furniture size, were subjected into anthropometric measurements (shoulder, elbow, knee and popliteal height, buttock-popliteal length and hip breadth). Combinational equations defined the acceptable furniture dimensions according to anthropometry and match percentages were computed, according to either the existing situation--where children use the size assigned for their grade--or assuming that they could use the most appropriate of the sizes available. Desk and seat height were bigger than the accepted limits for most children (81.8% and 71.5%, respectively), while seat depth was appropriate for only 38.7% of children. In conclusion, the assumption that children could use the most appropriate yet available size significantly improved the match, indicating that the limited provision of one size per cluster of grades does not accommodate the variability of anthropometry even among children of the same age. 相似文献
107.
In this paper we survey our research on smart meeting rooms and its relevance for augmented reality meeting support and virtual
reality generation of meetings in real time or off-line. The research reported here forms part of the European 5th and 6th
framework programme projects multi-modal meeting manager (M4) and augmented multi-party interaction (AMI). Both projects aim
at building a smart meeting environment that is able to collect multimodal captures of the activities and discussions in a
meeting room, with the aim to use this information as input to tools that allow real-time support, browsing, retrieval and
summarization of meetings. Our aim is to research (semantic) representations of what takes place during meetings in order
to allow generation, e.g. in virtual reality, of meeting activities (discussions, presentations, voting, etc.). Being able
to do so also allows us to look at tools that provide support during a meeting and at tools that allow those not able to be
physically present during a meeting to take part in a virtual way. This may lead to situations where the differences between
real meeting participants, human-controlled virtual participants and (semi-) autonomous virtual participants disappear.
相似文献
Dirk HeylenEmail: |
108.
The use of collaborative virtual environments in e-learning is one of the most promising uses of virtual reality technology. While much research has been done in the area of networked virtual environments corresponding to the sharing of events, very little research has been done on specific services and functionality. However both the requirements and the kind of the offered services affect significantly the design of a system. In this paper we present the design and implementation of a platform suitable for educational virtual environments, which are collaborative virtual environments aiming at offering collaborative e-learning services to the users. Apart from the platform itself, we present the technological choices, and a new method for sharing virtual environments. Furthermore, we present an e-learning environment to support e-learning services using collaborative virtual environments from both the technical and functional point of view, along with the end-user evaluation results.
相似文献
C. BourasEmail: |
109.
Paul F. Cleary Glenn Pierce Eileen M. Trauth 《Universal Access in the Information Society》2006,4(4):354-373
The purpose of this study is to explore the dynamics underlying disparities in Internet use among school age children in the
US. The analysis found that a broad range of demographic, geographic and economic factors significantly influence Internet
use among children. Significantly, the availability of household computing resources and adult Internet users in the household
were most important in explaining disparities in use among children. To expand universal Internet access, future public policy
should focus on providing support for in-home access; continued support for public access at out-of-home locations such as
schools, and providing technical support, training and expertise to school age children.
相似文献
Paul F. ClearyEmail: |
110.
School bus routing problems, combining bus stop selection and bus route generation, look simultaneously for a set of bus stops to pick up students from among a group of potential locations, and for bus routes to visit the selected stops and carry the students to their school. These problems, classified as Location-Routing problems, are of interest in densely populated urban areas.This article introduces a generalization of the vehicle routing problem called the multi-vehicle traveling purchaser problem, modeling a family of routing problems combining stop selection and bus route generation. It discusses a Mixed Integer Programming formulation extending previous studies on the classical single vehicle traveling purchaser problem. The proposed model is based on a single commodity flow formulation combining continuous variables with binary variables by means of coupling constraints. Additional valid inequalities are proposed with the purpose of strengthening its Linear Programming relaxation. These valid inequalities are obtained by projecting out the flow variables.We develop a branch-and-cut algorithm that makes use of the proposed model and valid inequalities. This cutting plane algorithm is implemented and tested on a large family of symmetric and asymmetric instances derived from randomly generated problems, showing the usefulness of the proposed valid inequalities. 相似文献