全文获取类型
收费全文 | 5784篇 |
免费 | 129篇 |
国内免费 | 27篇 |
专业分类
电工技术 | 435篇 |
综合类 | 17篇 |
化学工业 | 1579篇 |
金属工艺 | 154篇 |
机械仪表 | 145篇 |
建筑科学 | 194篇 |
矿业工程 | 1篇 |
能源动力 | 256篇 |
轻工业 | 539篇 |
水利工程 | 20篇 |
石油天然气 | 7篇 |
无线电 | 341篇 |
一般工业技术 | 992篇 |
冶金工业 | 414篇 |
原子能技术 | 231篇 |
自动化技术 | 615篇 |
出版年
2023年 | 30篇 |
2022年 | 65篇 |
2021年 | 106篇 |
2020年 | 57篇 |
2019年 | 66篇 |
2018年 | 80篇 |
2017年 | 68篇 |
2016年 | 120篇 |
2015年 | 83篇 |
2014年 | 153篇 |
2013年 | 334篇 |
2012年 | 202篇 |
2011年 | 323篇 |
2010年 | 272篇 |
2009年 | 291篇 |
2008年 | 333篇 |
2007年 | 285篇 |
2006年 | 227篇 |
2005年 | 235篇 |
2004年 | 195篇 |
2003年 | 172篇 |
2002年 | 174篇 |
2001年 | 116篇 |
2000年 | 106篇 |
1999年 | 117篇 |
1998年 | 192篇 |
1997年 | 136篇 |
1996年 | 106篇 |
1995年 | 76篇 |
1994年 | 97篇 |
1993年 | 87篇 |
1992年 | 59篇 |
1991年 | 82篇 |
1990年 | 58篇 |
1989年 | 81篇 |
1988年 | 70篇 |
1987年 | 43篇 |
1986年 | 76篇 |
1985年 | 58篇 |
1984年 | 56篇 |
1983年 | 60篇 |
1982年 | 61篇 |
1981年 | 49篇 |
1980年 | 43篇 |
1979年 | 43篇 |
1978年 | 43篇 |
1977年 | 32篇 |
1976年 | 34篇 |
1975年 | 19篇 |
1973年 | 19篇 |
排序方式: 共有5940条查询结果,搜索用时 0 毫秒
41.
The plasmodium of Physarum polycephalum is a unicellular and multinuclear giant amoeba that has an amorphous cell body. To clearly observe how the plasmodium makes decisions in its motile and exploratory behaviours, we developed a new experimental system to pseudo-discretize the motility of the organism. In our experimental space that has agar surfaces arranged in a two-dimensional lattice, the continuous and omnidirectional movement of the plasmodium was limited to the stepwise one, and the direction of the locomotion was also limited to four neighbours. In such an experimental system, a cellular automata-like system was constructed using the living cell. We further analysed the exploratory behaviours of the plasmodium by duplicating the experimental results in the simulation models of cellular automata. As a result, it was revealed that the behaviours of the plasmodium are not reproduced by only local state transition rules; and for the reproduction, a kind of historical rule setting is needed. 相似文献
42.
43.
In this paper, we propose a novel method to achieve both dense 3D reconstruction of the scene and estimation of the camera intrinsic parameters by using coplanarities and other constraints (e.g., orthogonalities or parallelisms) derived from relations between planes in the scene and reflected curves of line lasers captured by a single camera. In our study, we categorize coplanarities in the scene into two types: implicit coplanarities, which can be observed as reflected curves of line lasers, and explicit coplanarities, which are, for example, observed as walls of a building. By using both types of coplanarities, we can construct simultaneous equations and can solve them up to four degrees of freedom. To upgrade the solution to the Euclidean space and estimate the camera intrinsic parameters, we can use metric constraints such as orthogonalities of the planes. Such metric constraints are given by, for example, observing the corners of rectangular boxes in the scene, or using special laser projecting device composed of two line lasers whose laser planes are configured to be perpendicular. 相似文献
44.
This article proposes a function for color information detection using genetic programming (GP). In image-processing, object
detection is one of the important processes. In cases where the object has a complex color domain, detection becomes more
difficult. We generated a detection function for a complex color domain by using GP. The detection function deals with one
pixel of an input image, and it obtains an output image by processing for all pixels. We aimed at a reduction in the time
taken by a human to consider an image-processing system design. We applied the generation of GP to detect a target color region
in actual images. The results show that the detection function has sufficient ability for these detections. 相似文献
45.
Lydie du Bousquet Masahide Nakamura Ben Yan Hiroshi Igaki 《Innovations in Systems and Software Engineering》2009,5(3):181-196
A home network system consists of multiple networked appliances, intended to provide more convenient and comfortable living
for home users. Before being deployed, one has to guarantee the correctness, the safety, and the security of the system. Here,
we present the approach chosen to validate the Java implementation of a home network system. We rely on the Java Modelling
Language to formally specify and validate an abstraction of the system.
This is a substantially revised version of our paper that appeared in the proceedings of the Workshop On Leveraging Applications
of Formal Methods, Verification and Validation (ISoLA), Poitiers-Futuroscope, France, December 2007. 相似文献
46.
47.
48.
Hiroshi Kametani 《Metallurgical and Materials Transactions B》1998,29(6):1261-1267
Data concerning the length of longitudinal cracks on the surface of continuously cast steel slabs were collected from two
plants. The data were analyzed to find the relation between crack length and crack frequency. The analysis revealed the following.
相似文献
(1) |
After normalization to eliminate the effect of different casting conditions, the fractal relation characterizing the normalized
cumulative frequency distribution (N (m−2)) and the crack length (L (mm)) of the primary surface cracks could be represented by the equation |
|
(2) | The values for γ varied over a wide range, but remained constant throughout a heat and were the same for both the upper and lower faces of the slab. | |
(3) | It was found that in some instances, when L exceeded a critical value (L c), the value of L became δ times longer than the length predicted by the previous distribution. This increase in L was ascribed to secondary growth of the cracks. This occurred more frequently on the lower, rather than on the upper, face of the slab. The product of L c and δ was approximately constant. The formation of the surface cracks is discussed in view of the fractal phenomena. |
49.
C. Bäuerle N. Mori G. Kurata Hiroshi Fukuyama 《Journal of Low Temperature Physics》1998,113(5-6):927-932
Scanning tunneling microscopy (STM) studies of two-dimensional (2D) cryocrystals
4
He, Kr, Xe) physisorbed on graphite surfaces are presented. Individual helium atoms, usually thought to be invisible with STM, were recently observed on graphite surfaces at a density corresponding to the
commensurate solid. Here we show that a local elastic deformation seems to be the principal mechanism responsible to render the atoms visible. Recent tight-binding calculations of the local density of states (LDOS) of graphite which predict the appearance of an energy gap support this picture. I-z curve measurements for the case of
4
He show a sharp drop (increase) of the tunneling current I at a certain tip-surface distance z during retraction (approach) of the tip. This drop (increase) may be associated with the tunneling of a single He adatom, opening new possibilities to study the quantum tunneling of atoms via STM. 相似文献
50.
Hiroyuki Ishida Author Vitae Tomokazu Takahashi Author Vitae Author Vitae Hiroshi Murase Author Vitae 《Pattern recognition》2010,43(8):2799-2806
We propose a novel sequence alignment algorithm for recognizing handwriting gestures by a camera. In the proposed method, an input image sequence is aligned to the reference sequences by phase-synchronization of analytic signals which are transformed from original feature values. A cumulative distance is calculated simultaneously with the alignment process, and then used for the classification. A major benefit of this method is that over-fitting to sequences of incorrect categories is restricted. The proposed method exhibited higher recognition accuracy in handwriting gesture recognition, compared with the conventional dynamic time warping method which explores optimal alignment results for all categories. 相似文献