全文获取类型
收费全文 | 276篇 |
免费 | 11篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 18篇 |
综合类 | 13篇 |
化学工业 | 49篇 |
金属工艺 | 25篇 |
机械仪表 | 9篇 |
建筑科学 | 18篇 |
矿业工程 | 1篇 |
能源动力 | 8篇 |
轻工业 | 13篇 |
水利工程 | 2篇 |
石油天然气 | 2篇 |
武器工业 | 1篇 |
无线电 | 17篇 |
一般工业技术 | 48篇 |
冶金工业 | 36篇 |
原子能技术 | 7篇 |
自动化技术 | 33篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 12篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 10篇 |
2017年 | 7篇 |
2016年 | 5篇 |
2015年 | 8篇 |
2014年 | 10篇 |
2013年 | 10篇 |
2012年 | 12篇 |
2011年 | 14篇 |
2010年 | 13篇 |
2009年 | 16篇 |
2008年 | 11篇 |
2007年 | 8篇 |
2006年 | 14篇 |
2005年 | 13篇 |
2004年 | 12篇 |
2003年 | 9篇 |
2002年 | 6篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 11篇 |
1997年 | 7篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1970年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有300条查询结果,搜索用时 0 毫秒
51.
52.
53.
Daniel K. Owens N. P. Dhammika Nanayakkara Franck E. Dayan 《Journal of chemical ecology》2013,39(2):262-270
Leptospermone is a natural β-triketone that specifically inhibits the enzyme p-hydrophyphenylpyruvate dioxygenase, the same molecular target site as that of the commercial herbicide mesotrione. The β-triketone-rich essential oil of Leptospermum scoparium has both preemergence and postemergence herbicidal activity, resulting in bleaching of treated plants and dramatic growth reduction. Radiolabeled leptospermone was synthesized to investigate the in planta mechanism of action of this natural herbicide. Approximately 50 % of the absorbed leptospermone was translocated to the foliage suggesting rapid acropetal movement of the molecule. On the other hand, very little leptospermone was translocated away from the point of application on the foliage, indicating poor phloem mobility. These observations are consistent with the physico-chemical properties of leptospermone, such as its experimentally measured logP and pK a values, and molecular mass, number of hydrogen donors and acceptors, and number of rotatable bonds. Consequently, leptospermone is taken up readily by roots and translocated to reach its molecular target site. This provides additional evidence that the anecdotal observation of allelopathic suppression of plant growth under β-triketone-producing species may be due to the release of these phytotoxins in soils. 相似文献
54.
55.
56.
以广东某高层建筑为工程背景,针对大跨度转换结构,提出了双型钢混凝土转换梁柱节点的构造组合形式,通过对2个转换节点的竖向和水平荷载作用下的低周反复荷载试验,研究了节点的破坏形态、承载能力、刚度、滞回特性、延性、耗能能力及关键位置钢筋和型钢的应变等性能。试验结果表明:转换梁内置双型钢腹板形成的封闭空间对混凝土有约束作用,提高了节点区混凝土的抗剪能力;双型钢混凝土转换梁柱节点的滞回曲线饱满,极限变形能力较强,承载力较高,刚度、延性和耗能能力均较好;被转换柱与双型钢混凝土梁采用“端板螺栓连接”实现了“在被转换柱底部先出现塑性铰”,达到了“强梁强柱,更强节点”和“强转换层,弱框架层”目的。 相似文献
57.
58.
Abraham Kribus Daniel Kaftori Gur Mittelman Amir Hirshfeld Yuri Flitsanov Abraham Dayan 《Energy Conversion and Management》2006,47(20):3582-3590
A novel miniature concentrating PV (MCPV) system is presented and analyzed. The system is producing both electrical and thermal energy, which is supplied to a nearby consumer. In contrast to PV/thermal (PV/T) flat collectors, the heat from an MCPV collector is not limited to low-temperature applications. The work reported here refers to the evaluation and preliminary design of the MCPV approach. The heat transport system, the electric and thermal performance, the manufacturing cost, and the resulting cost of energy in case of domestic water heating have been analyzed. The results show that the new approach has promising prospects. 相似文献
59.
Ultrasonic sound velocity measurements were used to determine the elastic constants, Young, shear, and bulk moduli of polycrystalline,
β-stabilized uranium 1.6 and 2.3 at. pct gallium alloys, between 77 and 300 K. Measurements were also made, at constant heating
rate from 273 to 473 K, to follow the variation of the elastic constants during the transformation from the stabilized β into
the distorted orthorhombic α′-structure of uranium. The Young and shear moduli in the α′-structure are higher by about 30
pct than those in β-uranium. 相似文献
60.
G. Kimmel D. Dayan L. Zevin J. Pelleg 《Metallurgical and Materials Transactions A》1985,16(1):167-171
X-ray diffraction studies were used to investigate the wide solubility range of Ga in RGa2 type compounds observed in several systems of light rare earth metals (= R) with Ga. A model, based on pairwise substitution
of R atoms by Ga atoms, is suggested to explain the observed wide solubility. Using this model it is possible to explain the
change in lattice parameters of the ε phase having the formula R(1-x)Ga2(1+x). The structural relationships among the phases RGa2, R(1-x)Ga2(1+x,RGa6, and pure Ga are delineated, and the common feature of these phases which belong to widely different crystal systems is shown. 相似文献