全文获取类型
收费全文 | 3244篇 |
免费 | 78篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 128篇 |
综合类 | 7篇 |
化学工业 | 650篇 |
金属工艺 | 66篇 |
机械仪表 | 53篇 |
建筑科学 | 58篇 |
矿业工程 | 2篇 |
能源动力 | 99篇 |
轻工业 | 240篇 |
水利工程 | 6篇 |
石油天然气 | 2篇 |
无线电 | 393篇 |
一般工业技术 | 434篇 |
冶金工业 | 887篇 |
原子能技术 | 44篇 |
自动化技术 | 255篇 |
出版年
2023年 | 18篇 |
2022年 | 27篇 |
2021年 | 62篇 |
2020年 | 23篇 |
2019年 | 23篇 |
2018年 | 43篇 |
2017年 | 34篇 |
2016年 | 43篇 |
2015年 | 36篇 |
2014年 | 74篇 |
2013年 | 121篇 |
2012年 | 114篇 |
2011年 | 121篇 |
2010年 | 97篇 |
2009年 | 104篇 |
2008年 | 121篇 |
2007年 | 106篇 |
2006年 | 82篇 |
2005年 | 103篇 |
2004年 | 73篇 |
2003年 | 94篇 |
2002年 | 74篇 |
2001年 | 74篇 |
2000年 | 67篇 |
1999年 | 79篇 |
1998年 | 365篇 |
1997年 | 205篇 |
1996年 | 133篇 |
1995年 | 94篇 |
1994年 | 88篇 |
1993年 | 80篇 |
1992年 | 35篇 |
1991年 | 37篇 |
1990年 | 28篇 |
1989年 | 47篇 |
1988年 | 26篇 |
1987年 | 23篇 |
1986年 | 29篇 |
1985年 | 24篇 |
1984年 | 27篇 |
1983年 | 25篇 |
1982年 | 19篇 |
1981年 | 26篇 |
1980年 | 20篇 |
1979年 | 25篇 |
1978年 | 25篇 |
1977年 | 31篇 |
1976年 | 47篇 |
1974年 | 14篇 |
1973年 | 9篇 |
排序方式: 共有3324条查询结果,搜索用时 234 毫秒
951.
Mid-infrared radiation in the 5-18-mum range has been obtained by difference frequency generation in a AgGaSe(2) crystal by pumping with the output of a type I LiNbO(3) optical parametric oscillator (OPO). Here we suggest the use of a LiTaO(3) retarder to achieve an orthogonal state of polarization between OPO outputs that are necessary for efficient pumping of a AgGaSe(2) crystal. Several tens of kilowatts of peak power near 8 mum and continuously tunable operation in the above range have been obtained. 相似文献
952.
We have developed a diffractive micromachined chopper (DMC) for an IR wavelength of ~10 mum. This device operates mechanically by movable reflection grating beams. It modulates the diffraction efficiency by controlling the displacement of grating beams by an electrostatic force. For a CO(2) laser beam, a high modulation efficiency of 84% with an -0.8-dB small insertion loss was obtained by detecting 0th-order diffracted light. A novel pyroelectric IR microsensor with a DMC and a diffractive multilevel Si microlens was proposed and it demonstrated the detection of human existence. 相似文献
953.
A small-gain condition for iISS of interconnected retarded systems based on Lyapunov-Krasovskii functionals 总被引:1,自引:0,他引:1
This paper considers interconnected retarded nonlinear systems. Integral input-to-state stable subsystems and the construction of Lyapunov-Krasovskii functionals for their interconnections are focused on. Both discrete and distributed time-delays in the subsystems and the communication channels are covered. This paper provides a sufficient small-gain type condition for the stability of the interconnected systems with respect to external inputs in the framework of Lyapunov-Krasovskii functionals. Global asymptotic stability is addressed as a special case which deals with time-varying delays in communication channels effectively. 相似文献
954.
Nakagawa T Kurita N Kozakai S Iwabuchi S Yamaguchi Y Hayakawa M Ito Y Aoyama T Nakajima T 《Journal of molecular graphics & modelling》2008,27(1):45-58
Peroxisome proliferator-activated receptor α (PPARα) has various physiological functions such as lipid and glucose metabolism, inflammation and fibrosis in living organisms. Many types of ligand molecules such as phthalate and adipate esters control these physiological functions. In the present study, to elucidate the dependence of PPARα properties on ligand binding, we investigated stable structures and electronic properties for the complexes of PPARα and phthalate as well as adipate esters, which are used as a plasticizer, by molecular simulations based on molecular mechanics and molecular orbital methods. Furthermore, to elucidate the influence of these esters in vivo, we injected them into male mice and observed the change in the expression of PPARα-related enzymes. The comparison between the calculated and observed results indicates that the change in the expression has a correlation with the size of energy gaps between highest occupied and lowest unoccupied molecular orbitals of the complexes with mouse PPARα and esters. 相似文献
955.
Recently autonomous robot that is designed based on biological mechanism has attracted much attention. In this paper we focus
on mechanism of timing control which is studied in ecological psychology, and we apply it for controlling of multi mobile
robot. Simulations have been conducted and various flock behaviors have been realized. In addition, we have confirmed that
by using two leader robots, separation of flock is also possible. We can conclude that it is possible to realize flock behaviors
by using the timing control without information of distance.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
956.
Ayahiko Niimi Hiroshi Shimada Rika Goto Masaaki Wada Kei Ito Osamu Konishi 《Artificial Life and Robotics》2008,12(1-2):161-166
In this paper, we propose the technique of sensor data mining by the peer-to-peer (P2P) network. The mechanism that it is
possible to share on the P2P network is considered by receiving information from the sensor by the P2P application. A searching
request for a sensor unit and mining the sensor data occurs on the P2P application. We applied the proposed technique to a
school environment measurement system. In this system, sensor units are arranged on campus and a user can measure a room’s
temperature and humidity. The temperature sensor and the humidity sensor are implemented in a microcomputer board that can
connect to the Internet, and we define the microcomputer board as a sensor unit. We construct the P2P sensor network on which
a PC accesses the sensor unit and the P2P application on its PC uploads on the P2P network. The P2P network can disclose sensor
information after more advanced processing is given by thinking as a P2P application and not a sensor unit, but on the sensor
unit and the PC.
This work was presented in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January
25–27, 2007 相似文献
957.
Adaptive immunity based reinforcement learning 总被引:2,自引:2,他引:0
Jungo Ito Kazushi Nakano Kazunori Sakurama Shu Hosokawa 《Artificial Life and Robotics》2008,13(1):188-193
Recently much attention has been paid to intelligent systems which can adapt themselves to dynamic and/or unknown environments
by the use of learning methods. However, traditional learning methods have a disadvantage that learning requires enormously
long amounts of time with the degree of complexity of systems and environments to be considered. We thus propose a novel reinforcement
learning method based on adaptive immunity. Our proposed method can provide a near-optimal solution with less learning time
by self-learning using the concept of adaptive immunity. The validity of our method is demonstrated through some simulations
with Sutton’s maze problem.
This work was present in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February
2, 2008 相似文献
958.
Takao Ito Makoto Sakamoto Hiroshi Furutani Michio Kono Satoshi Ikeda 《Artificial Life and Robotics》2008,13(1):364-367
Informally, the parallel Turing machine (PTM) proposed by Wiedermann is a set of identical usual sequential Turing machines
(STMs) cooperating on two common tapes: storage tape and input tape. Moreover, STMs which represent the individual processors
of a parallel computer can multiply themselves in the course of computation. On the other hand, during the past 25 years or
so, automata on a three-dimensional tape have been proposed as computational models of three-dimensional pattern processing,
and several properties of such automata have been obtained. We proposed a three-dimensional parallel Turing machine (3-PTM),
and dealt with a hardware-bounded 3-PTM whose inputs are restricted to cubic ones. We believe that this machine is useful
in measuring the parallel computational complexity of three-dimensional images. In this article, we continue the study of
3-PTM, whose inputs are restricted to cubic ones, and investigate some of its accepting powers.
This work was presented in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January
25–27, 2007 相似文献
959.
Yasuyuki Sumi Sadanori Ito Tetsuya Matsuguchi Sidney Fels Shoichiro Iwasawa Kenji Mase Kiyoshi Kogure Norihiro Hagita 《Personal and Ubiquitous Computing》2007,11(4):265-271
This paper proposes a notion of interaction corpus, a captured collection of human behaviors and interactions among humans and artifacts. Digital multimedia and ubiquitous
sensor technologies create a venue to capture and store interactions that are automatically annotated. A very large-scale
accumulated corpus provides an important infrastructure for a future digital society for both humans and computers to understand
verbal/non-verbal mechanisms of human interactions. The interaction corpus can also be used as a well-structured stored experience,
which is shared with other people for communication and creation of further experiences. Our approach employs wearable and ubiquitous sensors, such as video cameras, microphones, and tracking tags, to capture all of the events from multiple viewpoints simultaneously.
We demonstrate an application of generating a video-based experience summary that is reconfigured automatically from the interaction
corpus.
相似文献
Yasuyuki SumiEmail: |
960.
Sean Xia Kwang‐Ohk Cheon Jason J. Brooks Mark Rothman Tan Ngo Patrick Hett Raymond C. Kwong Mike Inbasekaran Julie J. Brown Takuya Sonoyama Masaki Ito Shunichi Seki Satoru Miyashita 《Journal of the Society for Information Display》2009,17(2):167-172
Abstract— A new approach to full‐color printable phosphorescent organic light‐emitting devices (P2OLEDs) is reported. Unlike conventional solution‐processed OLEDs that contain conjugated polymers in the emissive layer, the P2OLED's emissive layer consists of small‐molecule materials. A red P2OLED that exhibits a luminous efficiency of 11.6 cd/A and a projected lifetime of 100,000 hours from an initial luminance of 500 cd/m2, a green P2OLED with a luminous efficiency of 34 cd/A and a projected lifetime of 63,000 hours from an initial luminance of 1000 cd/m2, a light‐blue P2OLED with a luminous efficiency of 19 cd/A and a projected lifetime 6000 hours from an initial luminance of 500 cd/m2, and a blue P2OLED with a luminous efficiency of 6.2 cd/A and a projected lifetime of 1000 hours from an initial luminance of 500 cd/m2 is presented. 相似文献