全文获取类型
收费全文 | 1530篇 |
免费 | 46篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 116篇 |
综合类 | 4篇 |
化学工业 | 442篇 |
金属工艺 | 51篇 |
机械仪表 | 42篇 |
建筑科学 | 37篇 |
能源动力 | 59篇 |
轻工业 | 125篇 |
水利工程 | 5篇 |
石油天然气 | 4篇 |
无线电 | 94篇 |
一般工业技术 | 284篇 |
冶金工业 | 130篇 |
原子能技术 | 41篇 |
自动化技术 | 152篇 |
出版年
2023年 | 6篇 |
2022年 | 18篇 |
2021年 | 35篇 |
2020年 | 14篇 |
2019年 | 9篇 |
2018年 | 31篇 |
2017年 | 18篇 |
2016年 | 33篇 |
2015年 | 29篇 |
2014年 | 49篇 |
2013年 | 91篇 |
2012年 | 78篇 |
2011年 | 117篇 |
2010年 | 58篇 |
2009年 | 78篇 |
2008年 | 93篇 |
2007年 | 78篇 |
2006年 | 54篇 |
2005年 | 61篇 |
2004年 | 62篇 |
2003年 | 52篇 |
2002年 | 34篇 |
2001年 | 47篇 |
2000年 | 24篇 |
1999年 | 28篇 |
1998年 | 44篇 |
1997年 | 39篇 |
1996年 | 28篇 |
1995年 | 23篇 |
1994年 | 32篇 |
1993年 | 29篇 |
1992年 | 12篇 |
1991年 | 19篇 |
1990年 | 15篇 |
1989年 | 24篇 |
1988年 | 14篇 |
1987年 | 15篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1980年 | 9篇 |
1979年 | 14篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1976年 | 4篇 |
1974年 | 3篇 |
1972年 | 1篇 |
排序方式: 共有1586条查询结果,搜索用时 15 毫秒
41.
We propose a recognition method of character-string images captured by portable digital cameras. A challenging task in character-string
recognition is the segmentation of characters. In the proposed method, a hypothesis graph is used for recognition-based segmentation
of the character-string images. The hypothesis graph is constructed by the subspace method, using eigenvectors as conditionally
elastic templates. To obtain these templates, a generation-based approach is introduced in the training stage. Various templates
are generated to cope with low-resolution. We have experimentally proved that the proposed scheme achieves high recognition
performance even for low-resolution character-string images.
The text was submitted by the authors in English.
Hiroyuki Ishida. Received his B.S. and M.S. degrees from the Department of Information Engineering and from the Graduate School of Information
Science, respectively, at Nagoya University. He is currently pursuing a Ph.D. in Information Science at Nagoya University.
Ichiro Ide. Received his B.S. degree from the Department of Electronic Engineering, his M.S. degree from the Department of Information
Engineering, and his Ph.D. from the Department of Electrical Engineering at the University of Tokyo. He is currently an Associate
Professor in the Graduate School of Information Science at Nagoya University.
Tomokazu Takahashi. Received his B.S. degree from the Department of Information Engineering at Ibaraki University, and his M.S. and Ph.D. from
the Graduate School of Science and Engineering at Ibaraki University. His research interests include computer graphics and
image recognition.
Hiroshi Murase. Received his B.S., M.S., and Ph.D. degrees from the Graduate School of Electrical Engineering at Nagoya University. He is
currently a Professor in the Graduate School of Information Science at Nagoya University. He received the Ministry Award from
the Ministry of Education, Culture, Sports, Science and Technology in Japan in 2003. He is a Fellow of the IEEE. 相似文献
42.
Masaki T Ishikawa T Paradis PF Yoda S Okada JT Watanabe Y Nanao S Ishikura A Higuchi K Mizuno A Watanabe M Kohara S 《The Review of scientific instruments》2007,78(2):026102
A compact electrostatic levitator was developed for the structural analysis of high-temperature liquids by x-ray diffraction methods. The size of the levitator was 200 mm in diameter and 200 mm in height and can be set up on a two axis diffractometer with a laboratory x-ray source, which is very convenient in performing structural measurements of high-temperature liquids. In particular, since the laboratory x-ray source allows a great amount of user time, preliminary or challenging experiments can be performed with trial and error, which prepares and complements synchrotron x-ray experiments. The present small apparatus also provides the advantage of portability and facility of setting. To demonstrate the capability of this electrostatic levitator, the static structure factors of alumina and silicon samples in their liquid phases were successfully measured. 相似文献
43.
重复控制系统中非周期扰动的抑制 总被引:3,自引:0,他引:3
为了改善重复控制系统中的扰动抑制性能,提出一种基于曲率模型的扰动估计新方法.该方法的主要特点是扰动的估计值直接与重复控制规则结合也不影响重复控制系统的稳定性.仿真结果显示该方法可以有效地抑制扰动. 相似文献
44.
Yasuhiro Kobayashi Masaaki Ohkita Michio Inoue 《Mathematics and computers in simulation》1976,18(2):115-122
For an analog simulating system, an approximating system is proposed. Its mathematical form is expressed by an algebraic equation: with four parameters given by real numbers. Their values can be determined so as to satisfy a best fit in a Chebyshev sense. Then, the accuracy is of the same order with that obtained by any kind of ordinary power series up to terms o f the third order. It is noticeable that a given function can be accurately approximated by this equation without destroying its uniform continuity.As its electronic system, it is possible to utilize forward current-voltage characteristics o f p-n diodes near their origins. Different functions can be produced by adjusting an amount o f ordinary resistances connected to diodes in series. 相似文献
45.
Yasuhiro Kodera Takeshi Yamamoto Naoki Toyofuku Manshi Ohyanagi Zuhair A. Munir 《Journal of Materials Science》2006,41(3):727-732
The ordering of stacking-disordered silicon carbide prepared from the elements by high energy ball milling was investigated
during sintering. A sharp increase in density in the temperature region 1700–1800°C was associated with a decrease in the
disorder. Samples which had low disorder density showed a more continuous sintering behavior with temperature. Highly dense
(up to 99% relative density) SiC can be obtained at 1900°C under a pressure of 70 MPa with no hold time. Similar results were
observed for structurally disordered carbon with 10 at% of boron. The sintering behavior exhibited an abrupt density increase
in the narrow temperature region of 1450–1600°C and was associated with disorder-order transformation. 相似文献
46.
Yasuhiro Konishi Takeshi TsukiyamaKaori Ohno Norizoh SaitohToshiyuki Nomura Shinsuke Nagamine 《Hydrometallurgy》2006
Microbial reduction and intracellular precipitation of gold was achieved at 25 °C and pH 7 by using the mesophilic anaerobic bacterium Shewanella algae with H2 as the electron donor. The reductive precipitation of gold by S. algae was a fast process: 0.1–1 mol/m3 AuCl4− ions were completely reduced to insoluble gold within 30 min. The biogenic precipitates were crystalline gold nanoparticles of 10–20 nm present in the periplasmic space. The reducing power of S. algae at 3.2 × 1015 cells/m3 and 25 °C was comparable to that of aqueous citric acid solution (chemical reductant) at 20 mol/m3 and 50 °C. The intracellular recovery of gold is potentially attractive as an environmentally friendly alternative to conventional methods. 相似文献
47.
Noriaki Murakami Koji Arafune Tadanobu Koyama Yoshimi Momose Tetsuo Ozawa Yasunori Okano Sadik Dost Le. H. Dao Masashi Kumagawa Yasuhiro Hayakawa 《Microgravity science and technology》2005,16(1-4):79-83
The effect of gravity on dissolution of GaSb in InSb melt and growth of InGaSb was experimentally investigated. Experiments were carried out in a GaSb(seed)/InSb/GaSb(feed) sandwich system under an imposed temperature gradient. In the experiments, the GaSb feed crystal dissolved into the InSb melt to supply the required GaSb component for the growth of In0.1Ga0.9Sb crystal. Two parameters were considered: (1) the inclination angle (θ) of the sample for gravity as 0° and 53°, and (2) the sample diameter (D) as 9 mm and 5mm. When θ was 0°, the interface was almost flat, indicating that convection was axisymmetric and stable. Whereas the interface was distorted towards gravitational direction when θ was 53°, indicating that solutal convection was dominant. The decrease of growth temperature and sample diameter reduced the distortion of interface and the dissolution amount of GaSb feed. The homogeneous crystals were grown at the initial growth stage by supplying the GaSb component during growth. 相似文献
48.
Yukimitsu Okano Tamio Kohriyama Yoshitaka Yoshida Michio Murase 《Nuclear Engineering and Design》2003,223(2):145-158
For severe accident assessment in a light water reactor, heat transfer models in a narrow annular gap between the overheated core debris and the reactor pressure vessel (RPV) are important for evaluating RPV integrity and emergency procedures. Using existing data, the authors developed heat transfer models on the average critical heat flux (CHF) restricted by countercurrent flow limitation (CCFL) and local boiling heat fluxes, and showed that the average CHF depended on the steam–water flow pattern in the narrow gap and that the local heat fluxes were similar to the pool boiling curve. We evaluated the validity of heat transfer models by simple calculations for ALPHA experiments performed at Japan Atomic Energy Research Institute. Calculated results showed that heat fluxes on the crust surface were restricted mainly by thermal resistance of the crust after the crust formation, and emissivity on the crust surface did not have much effect on the heat fluxes. The calculated vessel temperature during the heat-up process and peak vessel temperature agreed well with the measurements, which confirmed the validity of the average CHF correlation. However, the vessel cooling rate was underestimated mainly due to underestimation of the gap size. 相似文献
49.
A simultaneous detecting circuit system of centers and lengths of some lines in one dimension is presented applying an electronic circuit model of the nervous axon with respect to signal transmission. This model consists of series of one basic section, and has functions of Neuristor. The circuit system has a paralell processing function. It is constructed by three layers. In the first layer each visual signal of lines is changed to electric pulse signal. In the second layer edges of each line are detected, and in the third layer these detected signals are converted into voltages which correspond to lengths of the lines. These functions were confirmed experimentally using its hardware. 相似文献
50.
Parametric Feature Detection 总被引:7,自引:2,他引:7
Baker Simon Nayar Shree K. Murase Hiroshi 《International Journal of Computer Vision》1998,27(1):27-50
Most visual features are parametric in nature, including, edges, lines, corners, and junctions. We propose an algorithm to automatically construct detectors for arbitrary parametric features. To maximize robustness we use realistic multi-parameter feature models and incorporate optical and sensing effects. Each feature is represented as a densely sampled parametric manifold in a low dimensional subspace of a Hilbert space. During detection, the vector of intensity values in a window about each pixel in the image is projected into the subspace. If the projection lies sufficiently close to the feature manifold, the feature is detected and the location of the closest manifold point yields the feature parameters. The concepts of parameter reduction by normalization, dimension reduction, pattern rejection, and heuristic search are all employed to achieve the required efficiency. Detectors have been constructed for five features, namely, step edge (five parameters), roof edge (five parameters), line (six parameters), corner (five parameters), and circular disc (six parameters). The results of detailed experiments are presented which demonstrate the robustness of feature detection and the accuracy of parameter estimation. 相似文献