全文获取类型
收费全文 | 111598篇 |
免费 | 15346篇 |
国内免费 | 10911篇 |
专业分类
电工技术 | 16972篇 |
技术理论 | 14篇 |
综合类 | 12840篇 |
化学工业 | 3616篇 |
金属工艺 | 1865篇 |
机械仪表 | 5135篇 |
建筑科学 | 4787篇 |
矿业工程 | 2848篇 |
能源动力 | 2358篇 |
轻工业 | 1675篇 |
水利工程 | 2328篇 |
石油天然气 | 1869篇 |
武器工业 | 1049篇 |
无线电 | 23571篇 |
一般工业技术 | 4312篇 |
冶金工业 | 1755篇 |
原子能技术 | 294篇 |
自动化技术 | 50567篇 |
出版年
2024年 | 934篇 |
2023年 | 2399篇 |
2022年 | 4463篇 |
2021年 | 4936篇 |
2020年 | 5018篇 |
2019年 | 3590篇 |
2018年 | 2991篇 |
2017年 | 3547篇 |
2016年 | 3735篇 |
2015年 | 4282篇 |
2014年 | 7849篇 |
2013年 | 6686篇 |
2012年 | 8792篇 |
2011年 | 9137篇 |
2010年 | 6984篇 |
2009年 | 7295篇 |
2008年 | 7561篇 |
2007年 | 8457篇 |
2006年 | 7125篇 |
2005年 | 6302篇 |
2004年 | 5160篇 |
2003年 | 4575篇 |
2002年 | 3473篇 |
2001年 | 2909篇 |
2000年 | 2298篇 |
1999年 | 1845篇 |
1998年 | 1298篇 |
1997年 | 1038篇 |
1996年 | 847篇 |
1995年 | 636篇 |
1994年 | 487篇 |
1993年 | 321篇 |
1992年 | 206篇 |
1991年 | 138篇 |
1990年 | 106篇 |
1989年 | 98篇 |
1988年 | 62篇 |
1987年 | 31篇 |
1986年 | 34篇 |
1985年 | 51篇 |
1984年 | 36篇 |
1983年 | 32篇 |
1982年 | 36篇 |
1981年 | 12篇 |
1980年 | 6篇 |
1979年 | 11篇 |
1978年 | 3篇 |
1959年 | 5篇 |
1955年 | 2篇 |
1951年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
本文介绍了Windows环境下基于消息的DDE和基于动态链接库的DDEML的区别,并详细叙述了如何使用DDEML编制Windows应用程序。 相似文献
22.
Panagiotis N. Zarros Myung J. Lee Tarek N. Saadawi 《Journal of Network and Systems Management》1994,2(4):361-382
In this paper, an algorithm to determine the set of packets generated continuously and periodically from different participants that are arriving at a node either for mixing at the master of a conference, or for simply playing back at a regular participant of a conference, is proposed. The essence of the algorithm is to estimate the expected packet arrival time (or reference time) for each participant. With the reference time at hand, the maximum jitter and the optimum waiting time for a mixer to wait packets from all participants can be determined. An enhancement to improve synchronization which deals with the estimation of the time offsets between the individual periods of the sources and the period of the receiver is also presented. The error of the proposed algorithm is enumerated by the Chernoff bound and demonstrated by simulation and is shown to be acceptable in practical application. The algorithm can also be employed when traffic sources operate with different periods. 相似文献
23.
Claudia Popien Axel Kuepper Bernd Meyer 《Journal of Network and Systems Management》1994,2(4):383-400
New requirements of growing computer networks and information systems have an influence on extended client/server models with increased functionality. This forms the basis for service management in distributed systems which is realized by a service trading concept. This paper studies the requirements derived from the Open Distributed Processing (ODP) Reference Model in order to consider an open service market. Furthermore, it examines management possibilities for describing the service trading scenario. Because of similar architectures and properties ODP services, service offers, types, exporters and traders are mapped onto management components and modeled as managed objects. Therefore, the Guidelines for the Definition of Managed Objects (GDMO) are used. The final concept allows a precise and unambiguous study of the service trading scenario and provides means for exporting and importing of service offers in a distributed environment. 相似文献
24.
25.
In this paper, symbolic code matrix ,constant matrix and count matrix are defined .The first twomatrices are used to describe the elemental expression of augmented matrix and the nede admittance equa-tion is thus obtained. The third matrix is used to obtain the incoming degree matrix, and according to thematrix all the 1- factors of the Coates graph are given. By using the data code, the determinant is expandedand the same items in the expansion are merged. Thus the symbolic network function in which no term can-cellation occurs is generated. 相似文献
26.
阐述了加油站实施HSE管理,进行加油站风险评价的必要性,介绍了评价方法及其应用范围,评价组织的建立和工作流程及注意事项,指出:进行加油站风险评价,在选择评估方法时应从加油站的生产实际出发,针对不同的区域,采用适当的,可操作的方法;找出身边存在的危害因素,采取适当的措施来控制和化解风险,提高加油站安全管理水平,才能适应加入WTO后所面临的挑战。 相似文献
27.
28.
29.
Bandwidth Adaptation Algorithms for Adaptive Multimedia Services in Mobile Cellular Networks 总被引:3,自引:0,他引:3
The fluctuation of available link bandwidth in mobilecellular networks motivates the study of adaptive multimediaservices, where the bandwidth of an ongoing multimedia call can bedynamically adjusted. We analyze the diverse objectives of theadaptive multimedia framework and propose two bandwidth adaptationalgorithms (BAAs) that can satisfy these objectives. The firstalgorithm, BAA-RA, takes into consideration revenue and``anti-adaptation' where anti-adaptation means that a user feelsuncomfortable whenever the bandwidth of the user's call ischanged. This algorithm achieves near-optimal total revenue withmuch less complexity compared to an optimal BAA. The secondalgorithm, BAA-RF, considers revenue and fairness, and aims at themaximum revenue generation while satisfying the fairnessconstraint defined herein. Comprehensive simulation experimentsshow that the difference of the total revenue of BAA-RA and thatof an optimal BAA is negligible. Also, numerical results revealthat there is a conflicting relationship between anti-adaptationand fairness. 相似文献
30.