全文获取类型
收费全文 | 609篇 |
免费 | 9篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 28篇 |
综合类 | 2篇 |
化学工业 | 165篇 |
金属工艺 | 27篇 |
机械仪表 | 7篇 |
建筑科学 | 24篇 |
能源动力 | 28篇 |
轻工业 | 99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 | 10篇 |
原子能技术 | 45篇 |
自动化技术 | 55篇 |
出版年
2022年 | 25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 | 33篇 |
2012年 | 31篇 |
2011年 | 43篇 |
2010年 | 24篇 |
2009年 | 33篇 |
2008年 | 25篇 |
2007年 | 27篇 |
2006年 | 17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 | 9篇 |
1998年 | 11篇 |
1997年 | 10篇 |
1996年 | 11篇 |
1995年 | 8篇 |
1994年 | 11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624条查询结果,搜索用时 0 毫秒
1.
Tatsuya Hanaoka Hisashi Ishitani Ryuji Matsuhashi Yoshikuni Yoshida 《Applied Energy》2002,72(3-4):705-721
The objective of this study is to evaluate the potential for recovering fluorocarbons as measures for the abatement of global warming. In this study, we focused on the three different kinds of fluorocarbons: CFCs, HCFCs and HFCs, and targeted refrigerant use because of the availability of relevant data. We first estimated future fluorocarbon emissions from the targeted appliances; we next compared those emissions in the units of CO2 equivalent to the level of CO2 emissions in 1990 from a quantitative point of view. As the result of this study, it was found that fluorocarbon emissions in 1999 and 2010 would be equal to approximately 7 and 3% of the level of CO2 emissions in 1990 respectively. Moreover, if we implement a 100% recovery rate in every recovery route, we can reduce a large amount of emissions which correspond to approximately 2–5% of the level of CO2 emissions in 1990, even if we take into account the energy-related CO2 emissions by the transportation and decomposition of fluorocarbons. 相似文献
2.
Rinji Akada Yoshirou Shimizu Yuji Matsushita Miho Kawahata Hisashi Hoshida Yoshinori Nishizawa 《Yeast (Chichester, England)》2002,19(1):17-28
Drug-resistance markers for yeast transformation are useful because they can be applied to strains without auxotrophic mutations. However, they are susceptible to technical difficulties, namely lower transformation efficiency and the appearance of drug-resistant mutants without the marker. To avoid these problems, we have constructed a phosphoglycerate kinase (PGK) promoter-driven YAP1 expression cassette, called PGKp-YAP1. Yeast cells containing PGKp-YAP1 were resistant to cycloheximide, a protein synthesis inhibitor, and also to cerulenin, a fatty acid synthesis inhibitor, but not to other drugs tested. The transformation efficiency of PGKp-YAP1 using cerulenin selection was comparable to that using a URA3 auxotrophic marker when low concentrations of cerulenin were used. Non-transformed drug-resistant colonies did appear on the low-concentration cerulenin plates. However, these non-transformed colonies could easily be identified, based on their cycloheximide sensitivity and/or their resistance to aureobasidin A to which the transformants were sensitive. Therefore, the dual drug resistance of PGKp-YAP1 could be used as an effective selection for PGKp-YAP1 recipient cells. The PGKp-YAP1 marker was used to disrupt the LYS2 gene and to transform an industrial yeast strain, indicating that this marker can be used for efficient and reliable gene manipulations in any Saccharomyces cerevisiae strain. 相似文献
3.
Jiunn Yih Lee Hisashi Tanaka Hideo Takezoe Atsuo Fukuda Eiichi Kuze Hiroshi Iwanaga 《应用聚合物科学杂志》1984,29(3):795-802
A novel method is proposed of preparing thin Ag–Hg alloy on PAAm film surface at room temperature: The film of interest is formed by holding PAAm aqueous solution with AgNO3 in Hg-saturated atmosphere. Two kinds of films, one of which is a conductor and the other an insulator, can be selectively formed with pH-controlled PAAm solution by ammonia. The conducting surface is assigned to the α phase of Ag–Hg alloy by means of X-ray analysis. Potentiometric titration and IR spectral studies suggest the existence of PAAm–Ag+ complexes. On the basis of their structure and the oxidation and reduction potential of Ag+ and Hg2+, the mechanism of film formation is also discussed. 相似文献
4.
Minoru Tsuda Setsuko Oikawa Akira Yokota Mitsuo Yabuta Wataru Kanai Ken-Ichi Kashiwagi Isamu Hijikata Hisashi Nakane 《Polymer Engineering and Science》1983,23(18):993-999
A dry developable negative working resist composition comprised of poly(methyl isopropenyl ketone) (PMIPK) and 4-methyl-2,6-di(4′-azido-benzylidene) cyclohexanone-1 was examined. The main photochemical product formed in the resist pattern was found to be a secondary amine which crosslinks PMIPK. Post-annealing forms a hydrogen-bonded product which shows a powerful electronic excitation energy quenching effect. The quencher is more powerful than the aromatic compound arising from the azide by post-annealing only. The residual resist thickness of the negative pattern is about 80 percent of the initial thickness of the coating in spite of all the azide compound remaining in the resist coating. The obtained dry developed resist pattern has a high dry etch resistance. Etchings of Si and SiO2 were performed by plasma and reactive ion etching, respectively. 相似文献
5.
A novel method for three-dimensional observation of the vascular networks in the whole mouse brain 总被引:1,自引:0,他引:1
A novel method for acquiring serial images suitable for three-dimensional reconstruction of vascular networks in the whole brain of mouse was developed. The brain infused with a White India ink-gelatin solution was fixed and embedded in paraffin containing Sudan Black B through xylene also containing Sudan Black B. Each sliced surface of the paraffin block was coated with liquid paraffin and its image was serially acquired. Coating with liquid paraffin extremely improved the quality of the image. The series of serial images was free of distortion and a three-dimensional image was reconstructed without the problem of the alignment and registration of adjacent images. The volume-rendered image indicated three-dimensional distribution of blood vessels in a whole brain. No ghost or shadow was observed on a volume-rendered image of the White India ink-gelatin infused brain. The z-axial resolution examined on the orthogonal sections reconstituted from serial images obtained at an interval of 5 mum showed no cross talk, indicating that the z-axial resolution was no larger than 5 mum. A proper understanding of the vascular system in a whole brain is indispensable to reveal the development of the vascular system in the brain of normal and genetically manipulated mouse and vascular alterations in pathological situation, such as stroke and neurodegenerative disease. Although simple and inexpensive, this method will provide fundamental information on the vascular system in a whole brain. 相似文献
6.
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
7.
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
8.
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
9.
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
10.
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