全文获取类型
收费全文 | 595篇 |
免费 | 10篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 27篇 |
综合类 | 2篇 |
化学工业 | 160篇 |
金属工艺 | 27篇 |
机械仪表 | 7篇 |
建筑科学 | 24篇 |
能源动力 | 27篇 |
轻工业 | 97篇 |
石油天然气 | 1篇 |
无线电 | 31篇 |
一般工业技术 | 102篇 |
冶金工业 | 6篇 |
原子能技术 | 45篇 |
自动化技术 | 55篇 |
出版年
2022年 | 20篇 |
2021年 | 18篇 |
2020年 | 17篇 |
2019年 | 9篇 |
2018年 | 9篇 |
2017年 | 4篇 |
2016年 | 10篇 |
2015年 | 9篇 |
2014年 | 18篇 |
2013年 | 32篇 |
2012年 | 30篇 |
2011年 | 43篇 |
2010年 | 24篇 |
2009年 | 33篇 |
2008年 | 25篇 |
2007年 | 27篇 |
2006年 | 16篇 |
2005年 | 31篇 |
2004年 | 22篇 |
2003年 | 21篇 |
2002年 | 25篇 |
2001年 | 9篇 |
2000年 | 12篇 |
1999年 | 8篇 |
1998年 | 9篇 |
1997年 | 9篇 |
1996年 | 11篇 |
1995年 | 8篇 |
1994年 | 10篇 |
1993年 | 3篇 |
1992年 | 10篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 9篇 |
1988年 | 3篇 |
1987年 | 9篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有611条查询结果,搜索用时 31 毫秒
11.
Tree is a data structure used to express various objects such as semistructured data and genes. When objects are represented as trees, computing tree similarity is essential for pattern recognition and retrieval. This paper considers the noisy subsequence tree recognition problem whose purpose is to recognize the original tree, given its noisy subsequence tree. Previous research on this problem relied on constrained tree edit distance to measure the dissimilarity. However, the number of relabelings must be predetermined to compute it. This paper proposes a new dissimilarity measure for this problem. Our dissimilarity measure is obtained by counting the node edit operations included in the unit‐cost tree edit distance that contribute to the matching of node labels. The number of relabelings need not be specified to compute our dissimilarity measure. Moreover, our measure achieves more accurate recognition performance and faster execution speed than the constrained tree edit distance. Our measure is also useful to solve the tree inclusion problem which is the problem of deciding whether a tree includes another tree and shows the extent of approximate tree inclusion when a tree incompletely includes another tree. © 2011 Wiley Periodicals, Inc. 相似文献
12.
Tetsuo Yamada Naoyuki Mizuhara Hisashi Yamamoto Masayuki Matsui 《Computers & Industrial Engineering》2009,56(3):1113-1125
For sustainable manufacturing, manufacturers should construct and design inverse manufacturing systems consisting of assembly and disassembly systems. The sorting process in the disassembly system is the first process of the whole inverse manufacturing system. Therefore, it can become a bottleneck and decrease the productivity of the whole inverse manufacturing systems.This study focuses on a disassembly system with reverse blocking in a sorting process [Yamada, T., & Matsui, M. (2003). Disassembly production systems and its design issues. Reprints of Japan Industrial Management Association, Spring meeting, Chofu, Japan, May, 144–145 (in Japanese)]. It generalizes the queuing model and discusses the performance of the disassembly system by mathematical and numerical analysis. First, the sorting process with reverse blocking is generally modeled as a queuing system. Next, the stationary state equations of the system are formulated, and the objective function is set as the throughput. Finally, the system performance is discussed by mathematical and numerical analysis in cases of a different number of stations and buffers, and also an example of the system design is shown and discussed in view of the busy rate, blocking probability and throughput. 相似文献
13.
Kikuhito Kawasue Shoji Sakai Terufumi Wakiyama Shigeki Oyama Hisashi Senda 《Artificial Life and Robotics》2008,13(1):336-340
The 3D quantitative measurement system for a sewer pipe is introduced. Two parallel lasers are rotated by the motor and draw
the two annular streaks on the inside surface of the pipe. The circular laser streaks are recorded by the CCD camera. The
measurement of the cross-section is established by analyzing the recorded streaks. The tilt of the robot against the axis
of the pipe is detected by the deviation between two parallel lasers. It enables us to measure the vertical cross section
of the pipe regardless the tilt of the system to the pipe. Experimental result shows the feasibility of the system.
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
14.
Kazuyuki Maeshima Nanao Hayashi Tadayuki Murakami Fumiki Takahashi Hisashi Komae 《Journal of chemical ecology》1985,11(1):1-9
Chemical components stimulating oviposition bySitophilus zeamais in rice grain were isolated from rice bran and were found to be a mixture of ferulates, diglycerides, and free sterols. Oviposition preference of the species can be induced by synergistic action of these compounds. 相似文献
15.
Chemical and Chromatic Bases for Preferential Visiting By the Cabbage Butterfly, Pieris rapae, to Rape Flowers 总被引:1,自引:2,他引:1
Scent and coloration of corolla were examined as floral attributes responsible for preferential visiting by the cabbage butterfly, Pieris rapae, to rape flower, Brassica rapa. Floral volatile components that release the flower-visiting behavior of the butterfly were identified by chemical analyses, electroantennography (EAG), and two behavioral bioassays: proboscis extension reflex (PER) in response to odor and attraction to artificial flowers. GC and GC-MS analyses of the headspace volatiles from the flowers revealed the presence of six aromatic compounds, benzaldehyde, phenylacetaldehyde, benzyl alcohol, 2-phenylethanol, phenylacetonitrile, and indole in decreasing order of quantity. Of these, phenylacetaldehyde elicited the highest response in the PER assay. While benzyl alcohol, 2-phenylethanol, benzaldehyde, and phenylacetonitrile evoked moderate responses, the PER-eliciting activity of indole was very weak. In two-choice behavioral bioassays, artificial flowers scented with any one of these PER-active compounds attracted significantly more butterflies than control (unscented) flowers, whereas those treated with indole were almost inactive. The EAG activities of the six chemicals were not high and were about the same at a low dose (1 g), but phenylacetaldehyde elicited a much stronger response from both sexes at higher doses (10 and 100 g). An overall profile of EAG responses at a dose of 100 g was analogous to that of PER performance, suggesting that floral volatiles may be involved in close-range location or recognition of flowers rather than long-range attraction. By spectroscopic and UV-photographic examinations of rape flower, the central part of the corolla was found to absorb UV rays in marked contrast to the other parts, which reflected near-UV rays (max = 350 nm). This indicates that the flower is endowed with a conspicuous nectar guide that is probably an important visual stimulus for attracting foraging adults of P. rapae. Consequently, the present findings strongly suggest that this elaborate pollination strategy of rape flower, characterized by its good combination of olfactory and visual attractiveness, accounts for preferential visiting by the cabbage butterfly to the flower. 相似文献
16.
Yukio Yokoyama Hirofumi Kawashima Hisashi Kanie 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2006,53(5):847-852
Rectangular X-cut quartz crystal resonators with cut angles theta > 5.0 degrees and aspect ratios Rzy (= width 2z0/length 2y0) from 0.3 to 0.5 are investigated. The resonators oscillate mode is a length-extensional mode. A semiempirical frequency equation was derived from the stress expressed in terms of the trigonometric and the hyperbolic transcendental functions with constants estimated by the regression curve fit to the stress simulated by the finite-element method (FEM). Contours on which a point satisfies a zero first order temperature coefficient condition are shown in a cut angle theta and Rzy diagram. We proved that a fabricated resonator with Rzy = 0.400 and theta = 16.0 degrees, whose design parameter is located in the area of the contour, had a zero temperature coefficient. 相似文献
17.
Turbomolecular pumps (TMPs) are used extensively in several highly important areas of industry and research. The performances of TMP are evaluated by maximum throughput and maximum pressure ratio. In this paper, they are investigated by DSMC method. A 3D analysis in a rotating reference frame is proposed to simulate this flow field. Considering the Coriolis and centrifugal accelerations, the equations about the molecular velocities and position are deduced. The VSS model and NTC collision schemes are used to calculate the intermolecular collisions. The diffuse reflection is employed on the molecular reflection from the surfaces of boundary. The procedures for establishment of the correct collision rate are based on the cells, while individual collision pairs are chosen from the sub-cells. The pump performances of one stage TMP under the different kinds of gas, different heights, and different blade angles are simulated and the results are analyzed. Numerical results agree well with the existing experiment data. 相似文献
18.
Hisashi Abe Isao Yoshida Hiroki Hamada Derek Luke Yongbao Xin Yue Xu Rong Yang Eiric Johnstone Joe Acchione Paul Balmforth 《Journal of the Society for Information Display》2004,12(3):275-280
Abstract— Defect‐free large‐area inorganic thick‐dielectric EL (TDEL) displays using Color by Blue (CBB) technology have been successfully developed. We have achieved the world's highest blue‐phosphor luminance of 900 cd/m2 for a single‐pixel device by using CBB and by optimizing the e‐beam gun configuration and the flow rate of H2S in the vacuum chamber. By analyzing the defects on panels with triple‐pattern phosphors and CBB panels, we also found that the number of defects on CBB panels can be drastically reduced compared with those on triple‐pattern panels. The defect‐free 17‐in. VGA CBB panels show better characteristics, a high peak luminance of 600 cd/m2 and a high contrast ratio of 1000:1, compared with those of triple‐pattern panels. 相似文献
19.
20.
Naoki Kawara Hisashi Kurachi Takafumi Seto Seiji Kamba Takashi Kondo 《Aerosol science and technology》2016,50(6):535-541
Metal screens with uniform micrometer-sized opening were employed to sieve aerosol particles by suppressing the adhesion of particles smaller than the openings. The collection efficiencies of monodispersed polystyrene latex (PSL) particles were experimentally determined using the metal screens with 1.2, 1.8, 2.5, and 4.2 μm openings at various filtration velocities. The particles smaller than the mesh opening adhered on the metal screen at a low filtration velocity, but the bounce-off of particles on the mesh surface suppressed the adhesion at a high velocity. As a result, we found that the adhesion of PSL particles larger than 0.3 μm mostly suppressed at a filtration velocity higher than 10 m s?1 and therefore we can sieve aerosol particles according to the opening size of metal screens. We also found that the particle number concentration could be determined by measuring the increase in pressure drop since the clogging of metal screen openings takes place by the individual particles.© 2016 American Association for Aerosol Research 相似文献