全文获取类型
收费全文 | 1318篇 |
免费 | 71篇 |
专业分类
电工技术 | 21篇 |
综合类 | 2篇 |
化学工业 | 355篇 |
金属工艺 | 42篇 |
机械仪表 | 21篇 |
建筑科学 | 78篇 |
矿业工程 | 3篇 |
能源动力 | 47篇 |
轻工业 | 78篇 |
水利工程 | 11篇 |
石油天然气 | 2篇 |
无线电 | 80篇 |
一般工业技术 | 244篇 |
冶金工业 | 66篇 |
原子能技术 | 4篇 |
自动化技术 | 335篇 |
出版年
2023年 | 17篇 |
2022年 | 32篇 |
2021年 | 63篇 |
2020年 | 36篇 |
2019年 | 31篇 |
2018年 | 41篇 |
2017年 | 43篇 |
2016年 | 55篇 |
2015年 | 62篇 |
2014年 | 55篇 |
2013年 | 95篇 |
2012年 | 80篇 |
2011年 | 112篇 |
2010年 | 74篇 |
2009年 | 70篇 |
2008年 | 90篇 |
2007年 | 69篇 |
2006年 | 61篇 |
2005年 | 43篇 |
2004年 | 31篇 |
2003年 | 22篇 |
2002年 | 22篇 |
2001年 | 16篇 |
2000年 | 14篇 |
1999年 | 30篇 |
1998年 | 19篇 |
1997年 | 11篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1994年 | 14篇 |
1993年 | 4篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1958年 | 2篇 |
排序方式: 共有1389条查询结果,搜索用时 62 毫秒
71.
Satciety is a distributed parallel satisfiability (SAT) solver which focuses on tackling the domain-specific problems inherent to
one of the most challenging environments for parallel computing—Peer-to-Peer Desktop Grids. Satciety efficiently addresses issues related to resource volatility and heterogeneity, limited node and network capabilities, as
well as non-uniform communication costs. This is achieved through a sophisticated distributed task pool execution model, problem
size reduction through multi-stage SAT formula preprocessing, context-aware memory management, and adaptive topology-aware
distributed dynamic learning. Despite the demanding conditions prevailing in Desktop Grids, Satciety achieves considerable speedups compared to state-of-the-art sequential SAT solvers. 相似文献
72.
Die Dynamik der Technikentwicklung in den vergangenen Jahren konfrontiert Datenschützer immer wieder aufs Neue mit Risiken
für die Privatsph?re der Betroffenen — und es sieht so aus, als ob sich dies in den n?chsten Jahren und Jahrzehnten nicht
?ndern wird. Konzepte für einen lebenslangen Datenschutz erfordern ein Umdenken vom kurzatmigen Systementwurf zu langfristigen
und zukunftsf?higen Planungen. 相似文献
73.
Mladen Brnčić Tomislav Bosiljkov Marko Ukrainczyk Branko Tripalo Suzana Rimac Brnčić Sven Karlović Damir Karlović Damir Ježek Dražen Vikić Topić 《Food and Bioprocess Technology》2011,4(7):1296-1306
Production of extrudates from cereals is an often-used technological process in today’s world food industry. Extrudates from
corn flour produced using the twin-screw extrusion process and enriched with whey protein concentrate represent high-quality
source of proteins and fats. Whey protein concentrate (WPC) as a valuable source of proteins and minerals is one of the highest-quality
components for possible extrudate enrichment. In this paper, the influence of various WPC addition and some extrusion process
parameters such as feed moisture content (
Q\textH\text2 \textO Q_{{{\text{H}}_{\text{2}} {\text{O}}}} ) on physicochemical properties of directly expanded corn flour extrudates manufactured in twin-screw co-rotating extruder
was investigated. Whey protein concentrate was added in the following ratios 7.5%, 15% and 22.5% and water in 10.08, 12.18
and 14.28 L/h. Final composition of products is determined with measuring of protein, fat and water shares, water absorption
index (WAI) and water solubility index (WSI). With added WPC and with increase of water volume flow, there was a significant
rise in total protein, fat and water content in final products, as well as lowering of WSI and rising of WAI indexes. The
statistical analysis of the obtained data shows that the lowest WSI and the highest WAI had samples with the largest share
of WPC (22.5%) and water volume flow of 14.28 L/h. Colour is measured for each sample, and results were represented with hue
angle (H), chroma (C) and lightness (L) values. Process parameters, WPC and
Q\textH\text2 \textO Q_{{{\text{H}}_{\text{2}} {\text{O}}}} influence the increase of saturation of C and lightness of L colour value, while H value stays unchanged. Mean value of H
was 90.14 ± 1.06, which corresponds to dominance of yellow colour of samples. 相似文献
74.
The demand for biofuel pellets has increased considerably in recent years, causing shortage of the traditional raw materials sawdust and wood shavings. In this study, the costs and energy requirements for the production of pellets from agricultural raw materials were analysed. The materials studied were Salix, reed canary grass, hemp, straw, screenings, rape-seed meal, rape cake and distiller’s waste. Four production scales were analysed, having an annual output of 80,000, 8000, 800 and 80 tonnes of pellets per year. It was concluded that the raw materials of greatest interest were Salix and reed canary grass. They had competitive raw material costs and acceptable fuel properties and could be mixed with sawdust in existing large-scale pelleting factories. Straw had low production costs but can cause serious ash-related problems and should, as also is the case for screenings, be avoided in small-scale burners. Hemp had high raw material costs and is of less commercial interest, while distiller’s waste, rape-seed meal and rape cake had higher alternative values when used as protein feed. The scale of production had a crucial influence on production costs. The machinery was used much more efficiently in large-scale plants, resulting in clear cost savings. Small-scale pelleting, both static and mobile, required cheap raw materials, low labour costs and long utilisation times to be profitable. In most cases, briquetting would be more commercially viable. The energy use in manufacturing pellets from air-dried crops was generally no higher than when moist sawdust was used as the raw material. 相似文献
75.
Klaus Timmel Sven Eckert Gunter Gerbeth 《Metallurgical and Materials Transactions B》2011,42(1):68-80
This article describes laboratory experiments aimed at investigations of flow structures and related transport processes in
the continuous-casting mold under the influence of an external direct current (DC) magnetic field. The main value of cold
metal laboratory experiments consists in the capabilities to obtain quantitative flow measurements with a reasonable spatial
and temporal resolution. The experimental results presented here were obtained using a physical model operating with the room-temperature
alloy GaInSn. According to the concept of the electromagnetic brake, the impact of a DC magnetic field on the outlet flow
from the submerged entry nozzle (SEN) has been studied up to Hartmann numbers of approximately 400. The effect of the magnetic
field on the flow structure turned out to be complex. The flow measurements do not manifest a general braking effect, which
would be expected as an overall damping of the flow velocity and the related fluctuations all over the mold volume. Variations
of the wall conductivity showed a striking impact on the resulting flow structures. The experiments provide a substantial
database for the validation of respective numerical simulations. 相似文献
76.
77.
We prove a general monotonicity result about Nash flows in directed networks, which generalizes earlier results and can be
used for the design of truthful mechanisms in the setting where each edge of the network is controlled by a different selfish agent, who incurs costs when her edge
is used. 相似文献
78.
Optimal design applications are often modeled by using categorical variables to express discrete design decisions, such as
material types. A disadvantage of using categorical variables is the lack of continuous relaxations, which precludes the use
of modern integer programming techniques. We show how to express categorical variables with standard integer modeling techniques,
and we illustrate this approach on a load-bearing thermal insulation system. The system consists of a number of insulators
of different materials and intercepts that minimize the heat flow from a hot surface to a cold surface. Our new model allows
us to employ black-box modeling languages and solvers and illustrates the interplay between integer and nonlinear modeling
techniques. We present numerical experience that illustrates the advantage of the standard integer model. 相似文献
79.
80.