全文获取类型
收费全文 | 5460篇 |
免费 | 365篇 |
国内免费 | 246篇 |
专业分类
电工技术 | 97篇 |
综合类 | 322篇 |
化学工业 | 2010篇 |
金属工艺 | 455篇 |
机械仪表 | 580篇 |
建筑科学 | 161篇 |
矿业工程 | 66篇 |
能源动力 | 133篇 |
轻工业 | 199篇 |
水利工程 | 32篇 |
石油天然气 | 172篇 |
武器工业 | 26篇 |
无线电 | 236篇 |
一般工业技术 | 998篇 |
冶金工业 | 261篇 |
原子能技术 | 15篇 |
自动化技术 | 308篇 |
出版年
2024年 | 28篇 |
2023年 | 171篇 |
2022年 | 159篇 |
2021年 | 213篇 |
2020年 | 161篇 |
2019年 | 150篇 |
2018年 | 140篇 |
2017年 | 141篇 |
2016年 | 189篇 |
2015年 | 167篇 |
2014年 | 218篇 |
2013年 | 284篇 |
2012年 | 249篇 |
2011年 | 321篇 |
2010年 | 231篇 |
2009年 | 251篇 |
2008年 | 224篇 |
2007年 | 319篇 |
2006年 | 322篇 |
2005年 | 285篇 |
2004年 | 243篇 |
2003年 | 236篇 |
2002年 | 194篇 |
2001年 | 188篇 |
2000年 | 140篇 |
1999年 | 103篇 |
1998年 | 128篇 |
1997年 | 83篇 |
1996年 | 88篇 |
1995年 | 74篇 |
1994年 | 68篇 |
1993年 | 42篇 |
1992年 | 45篇 |
1991年 | 46篇 |
1990年 | 32篇 |
1989年 | 22篇 |
1988年 | 17篇 |
1987年 | 13篇 |
1986年 | 18篇 |
1985年 | 6篇 |
1984年 | 14篇 |
1983年 | 9篇 |
1982年 | 11篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1975年 | 2篇 |
1965年 | 2篇 |
1964年 | 3篇 |
1955年 | 2篇 |
排序方式: 共有6071条查询结果,搜索用时 281 毫秒
1.
2.
3.
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
4.
Electrochemical impedance spectroscopy (EIS), anodic polarization and scanning electron microscopy techniques were used to investigate the damage mechanism in the transpassive potential region of AISI ... 相似文献
5.
Erika Aparecida Silveira Golnaz Vaseghi Annelisa Silva de Carvalho Santos Nathalie Kliemann Farzad Masoudkabir Matias Noll Noushin Mohammadifard Nizal Sarrafzadegan Cesar de Oliveira 《International journal of molecular sciences》2020,21(23)
The association between obesity, cancer and cardiovascular disease (CVD) has been demonstrated in animal and epidemiological studies. However, the specific role of visceral obesity on cancer and CVD remains unclear. Visceral adipose tissue (VAT) is a complex and metabolically active tissue, that can produce different adipokines and hormones, responsible for endocrine-metabolic comorbidities. This review explores the potential mechanisms related to VAT that may also be involved in cancer and CVD. In addition, we discuss the shared pharmacological treatments which may reduce the risk of both diseases. This review highlights that chronic inflammation, molecular aspects, metabolic syndrome, secretion of hormones and adiponectin associated to VAT may have synergistic effects and should be further studied in relation to cancer and CVD. Reductions in abdominal and visceral adiposity improve insulin sensitivity, lipid profile and cytokines, which consequently reduce the risk of CVD and some cancers. Several medications have shown to reduce visceral and/or subcutaneous fat. Further research is needed to investigate the pathophysiological mechanisms by which visceral obesity may cause both cancer and CVD. The role of visceral fat in cancer and CVD is an important area to advance. Public health policies to increase public awareness about VAT’s role and ways to manage or prevent it are needed. 相似文献
6.
油田污水处理及酸化缓蚀剂的应用 总被引:6,自引:0,他引:6
介绍了油田污水处理及酸化中的几类缓蚀剂,重点介绍了咪唑啉型缓蚀剂、膦系缓蚀剂、曼尼希碱、炔醇等四类目前使用较多的缓蚀剂。结合缓蚀剂的分子结构阐述了其作用机理,论述了污水用缓蚀剂和酸化用缓蚀剂分子结构的区别及原因,并探讨了今后研究和发展的方向。 相似文献
7.
8.
改性双马来酰亚胺的研究 总被引:2,自引:0,他引:2
本文研究了双马来酰亚胺与烯丙基化合物形成的改性树脂体系的固化和热性能,讨论了单体配比、增韧剂、催化剂对性能的影响。 相似文献
9.
Recent developments in rubber-toughened structural acrylic adhesives now offer sheet steel fabricators the opportunity to replace conventional metal fastening techniques such as spot welding with lower cost, durable, more versatile structural adhesive bonding. These developments, in particular much improved ability to bond oily/waxy surfaces common to the motor car industry and improved retention of fracture toughness after exposure to paint stoving temperatures, are discussed in this paper. 相似文献
10.
Carboxyl‐terminated butadiene‐acrylonitrile rubber (CTBN) has often been used to improve the toughness of cyanate ester (CE) resin while sacrificing modulus and thermostability. In this paper, the addition of the appropriate amount of epoxy resin (EP) to the CE/CTBN system is shown to not only increase the modulus and thermostability of the blend, but also improve the toughness. The values of impact strength showed a maximum for the CE/CTBN/EP 100/5/5 blend. The temperature of 10 % weight loss (T10) improves from 376 °C for CE/CTBN 100/5 to 407 °C for the CE/CTBN/EP 100/5/2.5 blend. It is proposed that addition of the appropriate amount of EP can decrease the mobility and increase the stability of CTBN via the reaction between the terminal carboxyl group of CTBN and the hydroxyl group of EP. But a very high EP concentration will decrease the crosslinking density of CE, consequently reducing the mechanical properties and thermostability of the blends. Copyright © 2004 Society of Chemical Industry 相似文献