全文获取类型
收费全文 | 72630篇 |
免费 | 6307篇 |
国内免费 | 3172篇 |
专业分类
电工技术 | 4257篇 |
技术理论 | 10篇 |
综合类 | 4825篇 |
化学工业 | 12201篇 |
金属工艺 | 3865篇 |
机械仪表 | 4185篇 |
建筑科学 | 5762篇 |
矿业工程 | 1939篇 |
能源动力 | 2010篇 |
轻工业 | 5617篇 |
水利工程 | 1373篇 |
石油天然气 | 3986篇 |
武器工业 | 572篇 |
无线电 | 8662篇 |
一般工业技术 | 8948篇 |
冶金工业 | 3624篇 |
原子能技术 | 748篇 |
自动化技术 | 9525篇 |
出版年
2024年 | 333篇 |
2023年 | 1282篇 |
2022年 | 2300篇 |
2021年 | 3120篇 |
2020年 | 2432篇 |
2019年 | 1915篇 |
2018年 | 2181篇 |
2017年 | 2316篇 |
2016年 | 2250篇 |
2015年 | 2876篇 |
2014年 | 3595篇 |
2013年 | 4198篇 |
2012年 | 4620篇 |
2011年 | 5017篇 |
2010年 | 4146篇 |
2009年 | 3987篇 |
2008年 | 3902篇 |
2007年 | 3635篇 |
2006年 | 3477篇 |
2005年 | 2989篇 |
2004年 | 2237篇 |
2003年 | 1983篇 |
2002年 | 1806篇 |
2001年 | 1619篇 |
2000年 | 1764篇 |
1999年 | 2082篇 |
1998年 | 1767篇 |
1997年 | 1429篇 |
1996年 | 1428篇 |
1995年 | 1183篇 |
1994年 | 1039篇 |
1993年 | 706篇 |
1992年 | 549篇 |
1991年 | 400篇 |
1990年 | 339篇 |
1989年 | 308篇 |
1988年 | 222篇 |
1987年 | 156篇 |
1986年 | 111篇 |
1985年 | 81篇 |
1984年 | 61篇 |
1983年 | 41篇 |
1982年 | 52篇 |
1981年 | 33篇 |
1980年 | 39篇 |
1979年 | 15篇 |
1977年 | 9篇 |
1976年 | 13篇 |
1974年 | 11篇 |
1973年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
22.
23.
Yue Gao Miao-miao Zhang Xiao-peng Guo Wen-jian Li Dong Lu 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2020,95(5):1290-1297
Toxicity caused by the accumulation of butanol in fermentation media is an important factor limiting the concentration of butanol. There is currently no systematic research in place investigating the butanol tolerance mechanism of bacteria such as Clostridium acetobutylicum, which adapts to butanol stress and regulates its growth and metabolism. Here, research results related to the butanol tolerance of C. acetobutylicum are reviewed to understand the molecular basis of changes in butanol-tolerant strains. Organic solvent-tolerant bacteria play an important role in the fields of biofuel production, enzyme preparation and bioremediation. An analysis of limitations of the application of organic solvent-tolerant bacteria has revealed that future research should focus on combining the microbial tolerance phenotype with specific utilization to achieve an optimal balance between organic solvent tolerance and production. This review serves as a reference for the improvement and engineering of strains that tolerate organic solvents. © 2019 Society of Chemical Industry 相似文献
24.
Zu Guoqing Lu Yukuan Yan Yi Zhang Xiaoming Zhao Jingwei Du Wei Ran Xu Jiang Zhengyi 《Metals and Materials International》2020,26(2):248-259
Metals and Materials International - The flow behaviour and microstructure characteristics of a ferritic stainless steel were investigated using plain strain compression test on a Gleeble 3500... 相似文献
25.
Baizhan Li Chenqiu Du Hong Liu Wei Yu Jie Zheng Meilan Tan Zhenxing Jin Wenjie Li Jing Wu Lu Chen Runming Yao 《Indoor air》2019,29(2):308-319
The extensive research interests in environmental temperature can be linked to human productivity / performance as well as comfort and health; while the mechanisms of physiological indices responding to temperature variations remain incompletely understood. This study adopted a physiological sensory nerve conduction velocity (SCV) as a temperature‐sensitive biomarker to explore the thermoregulatory mechanisms of human responding to annual temperatures. The measurements of subjects’ SCV (over 600 samples) were conducted in a naturally ventilated environment over all four seasons. The results showed a positive correlation between SCV and annual temperatures and a Boltzmann model was adopted to depict the S‐shaped trend of SCV with operative temperatures from 5°C to 40°C. The SCV increased linearly with operative temperatures from 14.28°C to 20.5°C and responded sensitively for 10.19°C‐24.59°C, while tended to be stable beyond that. The subjects’ thermal sensations were linearly related to SCV, elaborating the relation between human physiological regulations and subjective thermal perception variations. The findings reveal the body SCV regulatory characteristics in different operative temperature intervals, thereby giving a deeper insight into human autonomic thermoregulation and benefiting for built environment designs, meantime minimizing the temperature‐invoked risks to human health and well‐being. 相似文献
26.
27.
28.
30.