全文获取类型
收费全文 | 1825篇 |
免费 | 33篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 20篇 |
化学工业 | 293篇 |
金属工艺 | 100篇 |
机械仪表 | 72篇 |
建筑科学 | 34篇 |
矿业工程 | 35篇 |
能源动力 | 25篇 |
轻工业 | 149篇 |
水利工程 | 93篇 |
石油天然气 | 230篇 |
无线电 | 80篇 |
一般工业技术 | 356篇 |
冶金工业 | 217篇 |
原子能技术 | 34篇 |
自动化技术 | 126篇 |
出版年
2022年 | 17篇 |
2018年 | 17篇 |
2017年 | 23篇 |
2016年 | 28篇 |
2013年 | 151篇 |
2012年 | 48篇 |
2011年 | 56篇 |
2010年 | 44篇 |
2009年 | 23篇 |
2008年 | 38篇 |
2007年 | 39篇 |
2006年 | 29篇 |
2004年 | 17篇 |
2003年 | 21篇 |
2002年 | 19篇 |
2001年 | 28篇 |
2000年 | 24篇 |
1999年 | 27篇 |
1998年 | 57篇 |
1997年 | 47篇 |
1996年 | 26篇 |
1994年 | 23篇 |
1993年 | 30篇 |
1992年 | 25篇 |
1991年 | 38篇 |
1990年 | 31篇 |
1989年 | 35篇 |
1988年 | 31篇 |
1987年 | 28篇 |
1986年 | 21篇 |
1985年 | 30篇 |
1984年 | 41篇 |
1982年 | 19篇 |
1981年 | 31篇 |
1980年 | 36篇 |
1979年 | 39篇 |
1978年 | 45篇 |
1977年 | 41篇 |
1976年 | 39篇 |
1975年 | 48篇 |
1974年 | 50篇 |
1973年 | 38篇 |
1972年 | 29篇 |
1971年 | 28篇 |
1970年 | 36篇 |
1969年 | 29篇 |
1968年 | 23篇 |
1967年 | 20篇 |
1966年 | 17篇 |
1965年 | 19篇 |
排序方式: 共有1864条查询结果,搜索用时 140 毫秒
21.
A technology for production of andalusite-based refractory components for the lining of anode firing kilns is described. The
formulation for a low-cement castable resistant to attack by molten aluminum is proposed.
__________
Translated from Novye Ogneupory, No. 4, pp. 109–111, April, 2006.
Based on materials reported to the conference “Aluminum of Siberia-2005.” 相似文献
22.
G. E. Zvigintseva R. M. Zbrozhek N. L. Nikolaeva Yu. G. Éismondt 《Metal Science and Heat Treatment》1991,33(4):300-303
1. | The stressed state of specimens after cooling in a polymer solution depends on polymer synthesis conditions. |
2. | In developing a procedure for control measurements of quenching agent composition during operation under production conditions and determination of the limiting permissible temperature of the quenching agent the properties of the concentrate used for preparing the quenching agent should be considered. |
23.
A. V. Zakharov Yu. E. Éismondt L. P. Shcherbakova É. L. Kolosova T. A. Trunina 《Metal Science and Heat Treatment》1991,33(4):294-299
1. | An agent based on polymer Na-CMC is more sensitive to an increase in temperature than an agent based on PK-2. An increase in aqueous Na-CMC solution temperature leads to a marked reduction in the heat removal coefficient in the pearlitic transformation temperature. |
2. | After quenching in 2.0–1.5% Na-CMC solution rails have a set of properties and structure close to similar characteristics obtained after bulk quenching in oil. |
3. | The properties and structure of rail plates after quenching in 0.5% aqueous Na-CMC solution corresponds to the requirements of TU 232-49-89. |
24.
Koczor Sándor Vuts József Caulfield John C. Withall David M. Sarria André Pickett John A. Birkett Michael A. Csonka Éva Bálintné Tóth Miklós 《Journal of chemical ecology》2021,47(6):525-533
Journal of Chemical Ecology - The sex pheromone composition of alfalfa plant bugs, Adelphocoris lineolatus (Goeze), from Central Europe was investigated to test the hypothesis that insect species... 相似文献
25.
In this paper, we present a method for binary image comparison. For binary images, intensity information is poor and shape extraction is often difficult. Therefore binary images have to be compared without using feature extraction. Due to the fact that different scene patterns can be present in the images, we propose a modified Hausdorff distance (HD) locally measured in an adaptive way. The resulting set of measures is richer than a single global measure. The local HD measures result in a local-dissimilarity map (LDMap) including the dissimilarity spatial layout. A classification of the images in function of their similarity is carried out on the LDMaps using a support vector machine. The proposed method is tested on a medieval illustration database and compared with other methods to show its efficiency. 相似文献
26.
Patrice Le Boudec François Sanchez Pierre-Luc FranÇois Jean-François Bayon Guy Michel StÉphan 《电信纪事》1994,49(3-4):178-192
The dynamics of the erbium doped fiber laser is analysed both experimentally and theoretically. This laser operates spontaneously in self-pulsing, in sinusoidal or in CW regime. Experiments have allowed to determine the control parameters : the cavity losses, the pumping rate and the ion pairs concentration. An antiphase dynamics is observed when the laser operates simultaneously at 1.55 µn and 1.536 µm. The self-pulsing behavior is attributed to a fast energy transfer which occurs between two neighboring ions (pair induced quenching). A simple model considering the active medium as a mixture of isolated ions and ions pairs is developped and leads to a good qualitative agreement with the experimental results. 相似文献
27.
Filamentary preforms of aluminium-13 wt % Si alloy reinforced with TiC-coated carbon fibres were obtained by liquid metal infiltration using K2ZrF6 as wetting agent. The interfacial structure was investigated using analytical electron microscopy (TEM, SEM) and the fibre strength measured following each step of processing. The reaction between the K2ZrF6 deposit and the molten alloy is discussed on the basis of the reaction products formed at the fibre-matrix interface, which mainly consisted of fluoride compounds (K3AlF6), different zirconium-rich suicides (Si2Zr, SiZr (Al), (Al, Si)2Zr) and crystalline -alumina. Large amounts and/or inhomogeneous distributions of the K2ZrF6 deposit should be avoided, because the massive precipitation of colonies of intermetallics around fibres is conducive for the formation of harmful aluminium carbides and favours brittle fracture of the composite. The utilization of TiC-coatings formed by the reactive chemical vapour deposition process gave satisfactory results, both in terms of composite elaboration and fibre protection during liquid infiltration. 相似文献
28.
29.
Étude O'Neel‐Judy Dylan Nicholls John Castañeda John G. Gibbs 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(32)
Using a dynamic fabrication process, hybrid, photoactivated microswimmers made from two different semiconductors, titanium dioxide (TiO2) and cuprous oxide (Cu2O) are developed, where each material occupies a distinct portion of the multiconstituent particles. Structured light‐activated microswimmers made from only TiO2 or Cu2O are observed to be driven in hydrogen peroxide and water most vigorously under UV or blue light, respectively, whereas hybrid structures made from both of these materials exhibit wavelength‐dependent modes of motion due to the disparate responses of each photocatalyst. It is also found that the hybrid particles are activated in water alone, a behavior which is not observed in those made from a single semiconductor, and thus, the system may open up a new class of fuel‐free photoactive colloids that take advantage of semiconductor heterojunctions. The TiO2/Cu2O hybrid microswimmer presented here is but an example of a broader method for inducing different modes of motion in a single light‐activated particle, which is not limited to the specific geometries and materials presented in this study. 相似文献
30.
Kalashnyk Nataliya Ledieu Julian Gaudry Émilie Cui Can Tsai An-Pang Fournée Vincent 《Nano Research》2018,11(4):2129-2138
Nano Research - The formation of long-range ordered aperiodic molecular films on quasicrystalline substrates is a new challenge that provides an opportunity for further surface functionalization.... 相似文献