全文获取类型
收费全文 | 22260篇 |
免费 | 1992篇 |
国内免费 | 933篇 |
专业分类
电工技术 | 1201篇 |
综合类 | 1030篇 |
化学工业 | 3744篇 |
金属工艺 | 1463篇 |
机械仪表 | 1642篇 |
建筑科学 | 1269篇 |
矿业工程 | 608篇 |
能源动力 | 816篇 |
轻工业 | 1523篇 |
水利工程 | 313篇 |
石油天然气 | 970篇 |
武器工业 | 115篇 |
无线电 | 2971篇 |
一般工业技术 | 3588篇 |
冶金工业 | 1243篇 |
原子能技术 | 184篇 |
自动化技术 | 2505篇 |
出版年
2024年 | 108篇 |
2023年 | 462篇 |
2022年 | 776篇 |
2021年 | 1111篇 |
2020年 | 826篇 |
2019年 | 678篇 |
2018年 | 820篇 |
2017年 | 776篇 |
2016年 | 802篇 |
2015年 | 914篇 |
2014年 | 1110篇 |
2013年 | 1346篇 |
2012年 | 1446篇 |
2011年 | 1607篇 |
2010年 | 1380篇 |
2009年 | 1353篇 |
2008年 | 1224篇 |
2007年 | 1015篇 |
2006年 | 974篇 |
2005年 | 850篇 |
2004年 | 651篇 |
2003年 | 635篇 |
2002年 | 590篇 |
2001年 | 498篇 |
2000年 | 465篇 |
1999年 | 472篇 |
1998年 | 455篇 |
1997年 | 353篇 |
1996年 | 326篇 |
1995年 | 260篇 |
1994年 | 209篇 |
1993年 | 137篇 |
1992年 | 111篇 |
1991年 | 77篇 |
1990年 | 74篇 |
1989年 | 63篇 |
1988年 | 43篇 |
1987年 | 34篇 |
1986年 | 33篇 |
1985年 | 22篇 |
1984年 | 17篇 |
1983年 | 10篇 |
1982年 | 8篇 |
1981年 | 15篇 |
1980年 | 10篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 10篇 |
1973年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
Knowledge and Information Systems - Given sequential news watch logs of users, how can we accurately recommend news articles? Compared to other items (e.g., movies and e-commerce products) for a... 相似文献
83.
Kang Ji-Hoon Hwang Jinyul Sung Hyung Jin Ryu Hoon 《The Journal of supercomputing》2021,77(9):9597-9614
The Journal of Supercomputing - Direct numerical simulations (DNS) of turbulent flows have increasing importance because they not only provide fundamental understanding of turbulent flows but also... 相似文献
84.
以TI公司的MSP430F5438单片机为控制核心,结合步进电机和精密电位器WDD35D-4,实现了基于自由摆的平板控制与激光追踪系统。当摆杆摆角为45°~60°时,平板可以承载8枚一元硬币,并在5个摆动周期内维持稳定;当摆杆摆角为30°~60°时,固定在摆杆平板上的激光笔可以在15s内找到并跟踪1.5m远处的靶心。 相似文献
85.
U Kang Hanghang Tong Jimeng Sun Ching-Yung Lin Christos Faloutsos 《The VLDB Journal The International Journal on Very Large Data Bases》2012,21(5):637-650
Graphs appear in numerous applications including cyber security, the Internet, social networks, protein networks, recommendation systems, citation networks, and many more. Graphs with millions or even billions of nodes and edges are common-place. How to store such large graphs efficiently? What are the core operations/queries on those graph? How to answer the graph queries quickly? We propose Gbase, an efficient analysis platform for large graphs. The key novelties lie in (1) our storage and compression scheme for a parallel, distributed settings and (2) the carefully chosen graph operations and their efficient implementations. We designed and implemented an instance of Gbase using Mapreduce/Hadoop. Gbase provides a parallel indexing mechanism for graph operations that both saves storage space, as well as accelerates query responses. We run numerous experiments on real and synthetic graphs, spanning billions of nodes and edges, and we show that our proposed Gbase is indeed fast, scalable, and nimble, with significant savings in space and time. 相似文献
86.
Due to the explosive increases of data from both the cyber and physical worlds, the demand for database support in embedded systems is increasing. Databases for embedded systems, or embedded databases, are expected to provide timely in situ data services under various resource constraints, such as limited energy. However, traditional buffer cache management schemes, in which the primary goal is to minimize the number of I/O operations, is problematic since they do not consider the constraints of modern embedded devices such as limited energy and distinctive underlying storage. In particular, due to asymmetric read/write characteristics of flash memory-based storage of modern embedded devices, minimum buffer cache misses neither coincide with minimum power consumption nor minimum I/O deadline misses. In this paper we propose a novel power- and time-aware buffer cache management scheme for embedded databases. A novel multi-dimensional feedback control architecture is proposed and the characteristics of underlying storage of modern embedded devices is exploited for the simultaneous support of the desired I/O power consumption and the I/O deadline miss ratio. We have shown through an extensive simulation that our approach satisfies both power and timing requirements in I/O operations under a variety of workloads while consuming significantly smaller buffer space than baseline approaches. 相似文献
87.
Chengcheng Zhou Kang Xue Lidan Gou Chunfang Sun Gangcheng Wang Taotao Hu 《Quantum Information Processing》2012,11(6):1765-1773
In this paper, a 3?×?3-matrix representation of Birman?CWenzl?CMurakami (BWM) algebra has been presented. Based on which, unitary matrices A(??, ?? 1, ?? 2) and B(??, ?? 1, ?? 2) are generated via Yang?CBaxterization approach. A Hamiltonian is constructed from the unitary B(??, ??) matrix. Then we study Berry phase of the Yang?CBaxter system, and obtain the relationship between topological parameter and Berry phase. 相似文献
88.
Jeong Won Kim Hee Won Kang Dong-Hwan Hwang Sang Jeong Lee 《International Journal of Control, Automation and Systems》2012,10(3):529-535
A signal tracking method of GNSS receivers for spinning vehicles is proposed in order to eliminate the influence of spinning to the GNSS signal of a vehicle. In the proposed method, a rotation tracking loop is added into the carrier tracking loop of a conventional GNSS receiver. The proposed method was verified through computer simulations and an experiment for live GPS signals. The results show that the proposed method gives an accurate tracking performance. 相似文献
89.
Ho-Chan Kim Hardian Reza Dharmayanda Taesam Kang Agus Budiyono Gigun Lee Widyawardana Adiprawita 《International Journal of Control, Automation and Systems》2012,10(1):88-101
Rigorous control synthesis for an unmanned aerial vehicle necessitates the availability of a good, reasonable model for such
a vehicle. The work reported in this paper focuses on the modeling of a rotary unmanned aerial vehicle (RUAV) and the development
of a robust controller that can handle parameter uncertainties and disturbances. The parameters of the plant model are obtained
through the use of the prediction error method with real flight data. The response of the identified linear model shows a
good match with the measured flight data. The H
∞ control scheme is applied to obtain a robustly stable controller using the identified model. The proposed controller is analyzed
using frequency-domain analysis and time-domain simulations. The performance of the proposed H
∞ controller is better than that of the conventional proportional derivative controller in that the proposed controller has
a shorter settling time and less overshoot. Furthermore, the degradation of the proposed controller performance is negligible
and stability is maintained when the input gains to the plant are doubled, which demonstrates the good performance and robustness
of the controller. 相似文献
90.
Dihua Zhai Yu Kang Ping Zhao Yun-Bo Zhao 《International Journal of Control, Automation and Systems》2012,10(6):1182-1192
The stability of a class of switched stochastic nonlinear retarded systems with asynchronous switching controller is investigated. By constructing a virtual switching signal and using the average dwell time approach incorporated with Razumikhin-type theorem, the sufficient criteria for pth moment exponential stability and global asymptotic stability in probability are given. It is shown that the stability of the asynchronous stochastic systems can be guaranteed provided that the average dwell time is sufficiently large and the mismatched time between the controller and the systems is sufficiently small. This result is then applied to a class of switched stochastic nonlinear delay systems where the controller is designed with both state and switching delays. A numerical example illustrates the effectiveness of the obtained results. 相似文献