全文获取类型
收费全文 | 531241篇 |
免费 | 4174篇 |
国内免费 | 1229篇 |
专业分类
电工技术 | 9657篇 |
综合类 | 577篇 |
化学工业 | 79178篇 |
金属工艺 | 19967篇 |
机械仪表 | 15224篇 |
建筑科学 | 12794篇 |
矿业工程 | 2269篇 |
能源动力 | 14629篇 |
轻工业 | 47355篇 |
水利工程 | 5441篇 |
石油天然气 | 9337篇 |
武器工业 | 37篇 |
无线电 | 60360篇 |
一般工业技术 | 102312篇 |
冶金工业 | 103503篇 |
原子能技术 | 10580篇 |
自动化技术 | 43424篇 |
出版年
2022年 | 3207篇 |
2021年 | 5141篇 |
2020年 | 3887篇 |
2019年 | 5025篇 |
2018年 | 7819篇 |
2017年 | 7627篇 |
2016年 | 8089篇 |
2015年 | 5616篇 |
2014年 | 9281篇 |
2013年 | 24092篇 |
2012年 | 14653篇 |
2011年 | 20168篇 |
2010年 | 15817篇 |
2009年 | 17705篇 |
2008年 | 18111篇 |
2007年 | 17788篇 |
2006年 | 15511篇 |
2005年 | 14214篇 |
2004年 | 13603篇 |
2003年 | 13401篇 |
2002年 | 12641篇 |
2001年 | 12842篇 |
2000年 | 11873篇 |
1999年 | 12600篇 |
1998年 | 32822篇 |
1997年 | 22900篇 |
1996年 | 17454篇 |
1995年 | 13043篇 |
1994年 | 11293篇 |
1993年 | 10978篇 |
1992年 | 7915篇 |
1991年 | 7422篇 |
1990年 | 7272篇 |
1989年 | 7016篇 |
1988年 | 6468篇 |
1987年 | 5766篇 |
1986年 | 5655篇 |
1985年 | 6265篇 |
1984年 | 5900篇 |
1983年 | 5172篇 |
1982年 | 4903篇 |
1981年 | 4966篇 |
1980年 | 4708篇 |
1979年 | 4609篇 |
1978年 | 4412篇 |
1977年 | 5337篇 |
1976年 | 6971篇 |
1975年 | 3796篇 |
1974年 | 3550篇 |
1973年 | 3665篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Lysunenko N.O. Brodnikovskyi Y.M. Mokiichuk V.M. Polishko I.O. Brodnikovskyi D.M. Chedryk V.I. Vasylyev O.D. 《Powder Metallurgy and Metal Ceramics》2021,60(5-6):352-359
Powder Metallurgy and Metal Ceramics - Fuel cells are today among the most efficient and environmentally friendly devices for the production of electricity. They are developing rapidly and are... 相似文献
82.
83.
84.
85.
I.P.L. Coleman J.A. Blair M.E. Hilburn 《The International journal of environmental studies》2013,70(3-4):187-191
The effect of a number of dietary and synthetic chelating agents on the intestinal absorption of lead has been examined using the everted sac preparation and the tracer isotope 203Pb. All the agents examined increased lead transport into the serosal compartment. An explanation of the way in which these agents modify the model to describe lead transport is proposed. 相似文献
86.
C. Chave C. Fairhurst M. Pugh Thomas 《The International journal of environmental studies》2013,70(4):245-251
The provision of countryside recreation facilities at a local level is likely to receive increasing attention during the next decade. As an integral part of the assessment of the quality of present provision within the Congleton District of Cheshire (U.K.) five site surveys were made. Each site provides different facilities for recreation and interview questions were designed to investigate the background of the visitors and the nature of the interplay between site and visitor. The analysis of answers attempts to illustrate those aspects of this interrelationship, which may be important during the consideration of future provision of recreation sites and their management. 相似文献
87.
88.
89.
90.
Pim M. A. Polesie 《Construction Management & Economics》2013,31(3):193-202
What construction firms do—and do not do—to reduce the use of resources in construction projects is explored by adopting production managers’ views of their firms’ onsite activities. A literature review and empirical data are combined; 15 production managers have been asked how they perceived their company’s compliance with 31 recommendations to reduce the use of resources. The managers perceived their firms to primarily focus on identifying their customers’ real needs, stimulating employees to undertake further education, and striving for long-term customer–supplier relationships. In contrast, they perceived that less attention was directed to making use of all of the week’s hours, to supporting their main suppliers in their development, and planning feedback and training after project completion. The use of resources is examined by focusing on the perceived low priority given to gathering information and knowledge, as well as to reducing time and the need for long-term relationships with customers in contrast to short-term relationships with suppliers. The managers adopted a project-specific approach mainly to the use of material resources. A more holistic view of resources could enable the development of novel solutions in construction. 相似文献