全文获取类型
收费全文 | 10347篇 |
免费 | 762篇 |
国内免费 | 780篇 |
专业分类
电工技术 | 311篇 |
综合类 | 1819篇 |
化学工业 | 263篇 |
金属工艺 | 88篇 |
机械仪表 | 402篇 |
建筑科学 | 369篇 |
矿业工程 | 70篇 |
能源动力 | 32篇 |
轻工业 | 662篇 |
水利工程 | 160篇 |
石油天然气 | 101篇 |
武器工业 | 42篇 |
无线电 | 723篇 |
一般工业技术 | 294篇 |
冶金工业 | 603篇 |
原子能技术 | 20篇 |
自动化技术 | 5930篇 |
出版年
2024年 | 42篇 |
2023年 | 117篇 |
2022年 | 218篇 |
2021年 | 253篇 |
2020年 | 188篇 |
2019年 | 142篇 |
2018年 | 120篇 |
2017年 | 182篇 |
2016年 | 212篇 |
2015年 | 220篇 |
2014年 | 484篇 |
2013年 | 475篇 |
2012年 | 603篇 |
2011年 | 664篇 |
2010年 | 611篇 |
2009年 | 623篇 |
2008年 | 735篇 |
2007年 | 768篇 |
2006年 | 741篇 |
2005年 | 695篇 |
2004年 | 543篇 |
2003年 | 535篇 |
2002年 | 365篇 |
2001年 | 362篇 |
2000年 | 291篇 |
1999年 | 217篇 |
1998年 | 184篇 |
1997年 | 170篇 |
1996年 | 129篇 |
1995年 | 140篇 |
1994年 | 134篇 |
1993年 | 105篇 |
1992年 | 83篇 |
1991年 | 79篇 |
1990年 | 46篇 |
1989年 | 54篇 |
1988年 | 41篇 |
1987年 | 27篇 |
1986年 | 22篇 |
1985年 | 43篇 |
1984年 | 43篇 |
1983年 | 23篇 |
1982年 | 10篇 |
1981年 | 14篇 |
1980年 | 12篇 |
1979年 | 10篇 |
1978年 | 13篇 |
1977年 | 10篇 |
1975年 | 15篇 |
1971年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
2.
Maqbool Ali Jamil Hussain Sungyoung Lee Byeong Ho Kang Kashif Sattar 《Expert Systems》2020,37(1):e12401
The case-based learning (CBL) approach has gained attention in medical education as an alternative to traditional learning methodology. However, current CBL systems do not facilitate and provide computer-based domain knowledge to medical students for solving real-world clinical cases during CBL practice. To automate CBL, clinical documents are beneficial for constructing domain knowledge. In the literature, most systems and methodologies require a knowledge engineer to construct machine-readable knowledge. Keeping in view these facts, we present a knowledge construction methodology (KCM-CD) to construct domain knowledge ontology (i.e., structured declarative knowledge) from unstructured text in a systematic way using artificial intelligence techniques, with minimum intervention from a knowledge engineer. To utilize the strength of humans and computers, and to realize the KCM-CD methodology, an interactive case-based learning system(iCBLS) was developed. Finally, the developed ontological model was evaluated to evaluate the quality of domain knowledge in terms of coherence measure. The results showed that the overall domain model has positive coherence values, indicating that all words in each branch of the domain ontology are correlated with each other and the quality of the developed model is acceptable. 相似文献
3.
This study develops a 6-DOF mathematical model for a robotic fish that considers surge, sway, heave, roll, pitch, and yaw. The model considers the conditions of a fish swimming in ocean current perturbations similar to the ocean current perturbations of the slender-body autonomous underwater vehicles. For swimming and turning behaviors, a nonlinear, dynamic, carangiform locomotion model is derived by using a planar four-link model. A 2-DOF barycenter mechanism is proposed to provide body stabilization and to serve as an actuating device for active control design. A barycenter control scheme is developed to change the center of gravity of the robot fish body by moving balancing masses along two axes. The projected torque on x and y axes propel pitch and roll angles to the desired settings. A Stabilizing controller, fish-tail mechanism, rigid body dynamics, and kinematics are incorporated to enable the fish robot to move in three dimensional space. Simulation results have demonstrated maneuverability and control system performance of the developed controller which is proposed to conduct path tracking of the robot fish as it swims under current perturbations. 相似文献
4.
Semantic search is gradually establishing itself as the next generation search paradigm, which meets better a wider range of information needs, as compared to traditional full-text search. At the same time, however, expanding search towards document structure and external, formal knowledge sources (e.g. LOD resources) remains challenging, especially with respect to efficiency, usability, and scalability.This paper introduces Mímir—an open-source framework for integrated semantic search over text, document structure, linguistic annotations, and formal semantic knowledge. Mímir supports complex structural queries, as well as basic keyword search.Exploratory search and sense-making are supported through information visualisation interfaces, such as co-occurrence matrices and term clouds. There is also an interactive retrieval interface, where users can save, refine, and analyse the results of a semantic search over time. The more well-studied precision-oriented information seeking searches are also well supported.The generic and extensible nature of the Mímir platform is demonstrated through three different, real-world applications, one of which required indexing and search over tens of millions of documents and fifty to hundred times as many semantic annotations. Scaling up to over 150 million documents was also accomplished, via index federation and cloud-based deployment. 相似文献
5.
首先介绍了HART通信协议及他的优点,然后介绍了HART通信协议在汽油机测速方面的软件实现。该软件主要采用目前流行的VB编程语言。可设计出界面友好、功能强大的测量和监控软件。 相似文献
6.
7.
空间机器人控制语言是实现空间机器人三种控制方式:遥控操作,自主操作和协同操作的软件基础,本文描述了该语言的基本结构,对于自主方式,给出了编程示例;对于遥控方式,运用程序辅助的方法,解决了操作员单独进行主/从操作时难以解决的问题. 相似文献
8.
We consider a language of operations which pass parameters by means of a stack. An algebra over the set of type signatures is introduced, which allows the type signature of a program to be obtained from the type signatures of its constituent operations.Although the theories apply in principle to any stack based language, they have been evolved with particular regard to the proposed ANSI Standard Forth language, which is currently implemented in a type free manner. We hope this work will stimulate an interest in Forth amongst those applying algebraic techniques in software engineering, and we hope to lay the theoretical foundations for implementing practical type checkers to support Forth. 相似文献
9.
Design and Implementation of a Flexible Manufacturing Control System Using Neural Network 总被引:1,自引:0,他引:1
Magdy M. Abdelhameed Farid A. Tolbah 《International Journal of Flexible Manufacturing Systems》2002,14(3):263-279
Design and implementation of a sequential controller based on the concept of artificial neural networks for a flexible manufacturing system are presented. The recurrent neural network (RNN) type is used for such a purpose. Contrary to the programmable controller, an RNN-based sequential controller is based on a definite mathematical model rather than depending on experience and trial and error techniques. The proposed controller is also more flexible because it is not limited by the restrictions of the finite state automata theory. Adequate guidelines of how to construct an RNN-based sequential controller are presented. These guidelines are applied to different case studies. The proposed controller is tested by simulations and real-time experiments. These tests prove the successfulness of the proposed controller performances. Theoretical as well as experimental results are presented and discussed indicating that the proposed design procedure using Elman's RNN can be effective in designing a sequential controller for event-based type manufacturing systems. In addition, the simulation results assure the effectiveness of the proposed controller to outperform the effect of noisy inputs. 相似文献
10.