全文获取类型
收费全文 | 280526篇 |
免费 | 3429篇 |
国内免费 | 1319篇 |
专业分类
电工技术 | 4842篇 |
综合类 | 527篇 |
化学工业 | 40771篇 |
金属工艺 | 11213篇 |
机械仪表 | 8491篇 |
建筑科学 | 6435篇 |
矿业工程 | 1589篇 |
能源动力 | 7118篇 |
轻工业 | 22621篇 |
水利工程 | 3060篇 |
石油天然气 | 5786篇 |
武器工业 | 43篇 |
无线电 | 33960篇 |
一般工业技术 | 57063篇 |
冶金工业 | 51139篇 |
原子能技术 | 7511篇 |
自动化技术 | 23105篇 |
出版年
2021年 | 2285篇 |
2019年 | 2134篇 |
2018年 | 3679篇 |
2017年 | 3745篇 |
2016年 | 3992篇 |
2015年 | 2545篇 |
2014年 | 4439篇 |
2013年 | 12131篇 |
2012年 | 7163篇 |
2011年 | 9855篇 |
2010年 | 7641篇 |
2009年 | 8871篇 |
2008年 | 9198篇 |
2007年 | 9215篇 |
2006年 | 7883篇 |
2005年 | 7317篇 |
2004年 | 7247篇 |
2003年 | 7025篇 |
2002年 | 6757篇 |
2001年 | 6889篇 |
2000年 | 6531篇 |
1999年 | 6800篇 |
1998年 | 16373篇 |
1997年 | 11625篇 |
1996年 | 8952篇 |
1995年 | 6884篇 |
1994年 | 6060篇 |
1993年 | 6098篇 |
1992年 | 4440篇 |
1991年 | 4226篇 |
1990年 | 4108篇 |
1989年 | 4078篇 |
1988年 | 3770篇 |
1987年 | 3412篇 |
1986年 | 3415篇 |
1985年 | 3760篇 |
1984年 | 3487篇 |
1983年 | 3230篇 |
1982年 | 3039篇 |
1981年 | 3046篇 |
1980年 | 3044篇 |
1979年 | 2843篇 |
1978年 | 2877篇 |
1977年 | 3153篇 |
1976年 | 4115篇 |
1975年 | 2418篇 |
1974年 | 2385篇 |
1973年 | 2401篇 |
1972年 | 2020篇 |
1971年 | 1785篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
75.
Rodríguez-Pérez Ángel Mariano Pérez-Calañas Cinta Pulido-Calvo Inmaculada 《Water Resources Management》2021,35(6):1977-1990
Water Resources Management - This paper aims to evaluate the possibility of using non-utilized hydraulic energy in urban water distribution systems. For this purpose, the viability and possible... 相似文献
76.
Wireless Personal Communications - Cloud computing is a growing technology where lot of heterogeneous resources are available and large amount of requests are submitted by the customers... 相似文献
77.
Influence of Wheel Blunting on the Machining Precision in CNC Plunge Grinding: Digital Twin Analysis
Akintseva A. V. Pereverzev P. P. Prokhorov A. V. Omel’chenko S. V. 《Russian Engineering Research》2022,42(7):726-730
Russian Engineering Research - The machining precision in grinding a flexible shaft by sharp and blunt wheels is compared for a CNC system with a specified cycle of radial supply velocities. To... 相似文献
78.
79.
Kooij Julian F. P. Flohr Fabian Pool Ewoud A. I. Gavrila Dariu M. 《International Journal of Computer Vision》2019,127(3):239-262
International Journal of Computer Vision - Anticipating future situations from streaming sensor data is a key perception challenge for mobile robotics and automated vehicles. We address the problem... 相似文献
80.
Roselle Barretto Rania Marie Buenavista Jared Lou Rivera Shuyu Wang P.V. Vara Prasad Kaliramesh Siliveru 《International Journal of Food Science & Technology》2021,56(7):3125-3137
The demand for food production has been constantly increasing due to rising population. In developed countries, for example, the emergence of regional production of old grains that are rarely utilized, along with the production of commonly consumed grains, has gained importance in recent years. These grains, known collectively as ancient or heirloom grains, have offered both farmers and consumers novel ways of cultivation and products with interesting taste, characteristics and nutritional value. Among the 30 000 plant species known, only five cereals currently provide more than 50% of the world's energy intake – bread wheat (Triticum aestivum), rice (Oryza sativa), sorghum (Sorghum bicolor), millets (Panicum sp.) and maize (Zea mays). The excessive utilization of these selected species has a great potential to cause genetic losses and difficulty in bridging future agricultural demands. Teff (Eragrostis tef), an ancient grain extensively cultivated in countries like Eritrea and Ethiopia, provides promising alternatives for new food uses since its nutritional value is significantly higher than most others cereal grains. The absence of gluten allows flexibility in food utilization since it can be directly substituted to gluten-containing products. The grain also offers an excellent balance of essential amino acids and minerals, which can fulfil the recommended daily intake and eliminates the need for fortification and enrichment. This review provides a general overview of the physical properties and nutritional composition of teff grains related to processing and applications in the food and feed industries. The current status of teff utilization, as well as the challenges in production and commercialization, and future opportunities is presented and discussed. 相似文献