全文获取类型
收费全文 | 2991篇 |
免费 | 109篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 169篇 |
综合类 | 3篇 |
化学工业 | 807篇 |
金属工艺 | 71篇 |
机械仪表 | 86篇 |
建筑科学 | 84篇 |
能源动力 | 114篇 |
轻工业 | 358篇 |
水利工程 | 12篇 |
石油天然气 | 1篇 |
无线电 | 201篇 |
一般工业技术 | 529篇 |
冶金工业 | 277篇 |
原子能技术 | 112篇 |
自动化技术 | 289篇 |
出版年
2023年 | 24篇 |
2022年 | 24篇 |
2021年 | 87篇 |
2020年 | 25篇 |
2019年 | 37篇 |
2018年 | 77篇 |
2017年 | 59篇 |
2016年 | 103篇 |
2015年 | 54篇 |
2014年 | 96篇 |
2013年 | 180篇 |
2012年 | 160篇 |
2011年 | 191篇 |
2010年 | 153篇 |
2009年 | 167篇 |
2008年 | 180篇 |
2007年 | 137篇 |
2006年 | 116篇 |
2005年 | 122篇 |
2004年 | 101篇 |
2003年 | 88篇 |
2002年 | 88篇 |
2001年 | 62篇 |
2000年 | 42篇 |
1999年 | 53篇 |
1998年 | 123篇 |
1997年 | 92篇 |
1996年 | 60篇 |
1995年 | 43篇 |
1994年 | 47篇 |
1993年 | 42篇 |
1992年 | 21篇 |
1991年 | 23篇 |
1990年 | 18篇 |
1989年 | 29篇 |
1988年 | 15篇 |
1987年 | 17篇 |
1986年 | 20篇 |
1985年 | 26篇 |
1984年 | 15篇 |
1983年 | 21篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 13篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1974年 | 7篇 |
排序方式: 共有3113条查询结果,搜索用时 17 毫秒
81.
For a robot to cohabit with people, it should be able to learn people’s nonverbal social behavior from experience. In this
paper, we propose a novel machine learning method for recognizing gestures used in interaction and communication. Our method
enables robots to learn gestures incrementally during human–robot interaction in an unsupervised manner. It allows the user
to leave the number and types of gestures undefined prior to the learning. The proposed method (HB-SOINN) is based on a self-organizing
incremental neural network and the hidden Markov model. We have added an interactive learning mechanism to HB-SOINN to prevent
a single cluster from running into a failure as a result of polysemy of being assigned more than one meaning. For example,
a sentence: “Keep on going left slowly” has three meanings such as, “Keep on (1)”, “going left (2)”, “slowly (3)”. We experimentally tested the clustering performance of the proposed method against data obtained from measuring gestures
using a motion capture device. The results show that the classification performance of HB-SOINN exceeds that of conventional
clustering approaches. In addition, we have found that the interactive learning function improves the learning performance
of HB-SOINN. 相似文献
82.
83.
A pneumatic actuator is suitable and safe for in-pipe inspection robots in inflammable circumstances because of its ability to withstand explosions. However, ordinary pneumatic actuators limit driving speed because of their slow response. In this paper, we propose a novel pneumatic drive mechanism that can produce a high-impact force to move the in-pipe robot forward with sufficient speed by a catastrophic phenomenon using rapid release between a magnet and springs. We also introduce an anisotropic friction mechanism that uses a self-locking phenomenon to transmit the impact force to the pipe walls efficiently. A pin retraction mechanism that releases the self-locking condition is applied to retrieve the robot from the pipes. Optimizations of the proposed design were conducted based on a motion simulation model and verified in experiments. The experimental results obtained for maximum driving speeds in a straight pipe with different material types were approximately 90 and 50 mm/s for horizontal and vertical pipes, respectively. Stable strokes were also observed at different driving frequencies from 0.5 to 2.0 Hz. 相似文献
84.
85.
A quantum-inspired evolutionary algorithm (QEA) is proposed as a stochastic algorithm to perform combinatorial optimization
problems. The QEA is evolutionary computation that uses quantum bits and superposition states in quantum computation. Although
the QEA is a coarse-grained parallel algorithm, it involves many parameters that must be adjusted manually. This paper proposes
a new method, named pair swap, which exchanges each best solution information between two individuals instead of migration
in the QEA. Experimental results show that our proposed method is a simpler algorithm and can find a high quality solution
in the 0-1 knapsack problem.
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
86.
Makoto Sakamoto Kaoru Kajisa Naoko Tomozoe Takao Ito Hiroshi Furutani Michio Kono Satoshi Ikeda 《Artificial Life and Robotics》2008,13(1):61-64
In 1997, C.R. Dyer and A. Rosenfeld introduced an acceptor on a two-dimensional pattern (or tape), called the pyramid cellular acceptor, and demonstrated that many useful recognition tasks are executed by pyramid cellular acceptors in time proportional to the
logarithm of the diameter of the input. They also introduced a bottom-up pyramid cellular acceptor which is a restricted version of the pyramid cellular acceptor, and proposed some interesting open problems of the bottom-up
pyramid cellular acceptors. On the other hand, we think that the study of threedimensional automata has been meaningful as
the computational model of three-dimensional information processing such as computer vision, robotics, and so forth. In this
paper, we investigate about bottom-up pyramid cellular acceptors with three-dimensional layers, and show their some accepting
powers.
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
87.
Tetsu Ando Hirokazu Ohsawa Tadahiro Ueno Hideki Kishi Yutaka Okamura Satoshi Hashimoto 《Journal of chemical ecology》1993,19(4):787-798
Although several sex pheromones of the family Geometridae have been characterized, investigations on Japanese species are limited. In order to obtain more information, screening using known sex pheromones and their analogs was carried out. The (Z,Z,Z)-3,6,9-triunsaturated and (Z,Z)-6,9-diunsaturated hydrocarbons with straight C19-C21 chains were synthesized by the Grignard coupling reaction as a key step starting from linolenic and linoleic acids, respectively. Oxidation of the homoconjugated trienes withm-chloroperoxybenzoic acid yielded a 111 mixture of three monoepoxy derivatives that could be separated by silica gel chromatography. The chemical structure of each positional isomer was confirmed using two-dimensional NMR techniques and MS measurements, which enabled characteristic fragment ions from the isomers to be identified. Field tests using lures incorporating only one of the above six hydrocarbons or nine epoxides were carried out in a forest in Tokyo. Consequently, attraction of male moths of 14 geometrid species in addition to four species in another family, the Noctuidae, was observed. It was concluded that hydrocarbons with a homoconjugated polyene system and the monoepoxy derivatives are important components of sex pheromones produced by Japanese lepidopterous insects, particularly the geometrid moths. 相似文献
88.
89.
Kawakami S 《Applied optics》1983,22(16):2426-2428
Analysis and experiments on TE and TM waves along periodically laminated metal-dielectric layers are described; the waves propagate parallel to the layers. Aluminum (Al) and silica (SiO2) are chosen as the metal and the dielectric, respectively. We find that the attenuation for TE waves is much higher than that for TM waves. Typically, alphaTE/alphaTM ranges from 10(3) to 10(4). Thus, an optical polarizer can be made in a multilayer structure. 相似文献
90.
Humans and animals seek appropriate solutions to novel problems through trial-and-error (TE) actions and observation of their outcomes. Once an individual has obtained the knowledge (rule) to solve a problem, knowledge-based (KB) actions may be applied in a stereotypical manner. Solutions can thus be based on TE or KB actions. To characterize this learning process at the behavioral level, we developed a new cognitive task for a laboratory monkey (Macaca fuscata) to perform. In this task, a search array consisting of six elements of different colors was presented, one of which was the behaviorally relevant target. The target color was changed unpredictably with no instruction or signal, requiring the monkey to use a TE search strategy to find the target color. We found that once the monkey identified the relevant color by chance after a color change, correct performance increased in a step-like manner and at the same time, other response properties (reaction time and color-choice tendency) also changed discontinuously. These step-like alternations in behavioral performance may be attributed to the subject’s switching between TE and KB search strategies in the two phases. The present study has therefore provided behavioral evidence for the timing and manner of switching between search strategies during the process of updating knowledge. 相似文献