全文获取类型
收费全文 | 57329篇 |
免费 | 6221篇 |
国内免费 | 3778篇 |
专业分类
电工技术 | 4338篇 |
技术理论 | 3篇 |
综合类 | 5503篇 |
化学工业 | 8319篇 |
金属工艺 | 3305篇 |
机械仪表 | 3823篇 |
建筑科学 | 4298篇 |
矿业工程 | 2293篇 |
能源动力 | 1817篇 |
轻工业 | 5061篇 |
水利工程 | 1550篇 |
石油天然气 | 2380篇 |
武器工业 | 597篇 |
无线电 | 6200篇 |
一般工业技术 | 6081篇 |
冶金工业 | 2637篇 |
原子能技术 | 772篇 |
自动化技术 | 8351篇 |
出版年
2024年 | 296篇 |
2023年 | 956篇 |
2022年 | 1807篇 |
2021年 | 2551篇 |
2020年 | 1901篇 |
2019年 | 1552篇 |
2018年 | 1609篇 |
2017年 | 1777篇 |
2016年 | 1653篇 |
2015年 | 2394篇 |
2014年 | 2958篇 |
2013年 | 3611篇 |
2012年 | 3968篇 |
2011年 | 4059篇 |
2010年 | 3770篇 |
2009年 | 3577篇 |
2008年 | 3587篇 |
2007年 | 3448篇 |
2006年 | 3157篇 |
2005年 | 2681篇 |
2004年 | 2197篇 |
2003年 | 2367篇 |
2002年 | 3089篇 |
2001年 | 2659篇 |
2000年 | 1587篇 |
1999年 | 1028篇 |
1998年 | 593篇 |
1997年 | 474篇 |
1996年 | 387篇 |
1995年 | 358篇 |
1994年 | 283篇 |
1993年 | 181篇 |
1992年 | 176篇 |
1991年 | 149篇 |
1990年 | 97篇 |
1989年 | 84篇 |
1988年 | 65篇 |
1987年 | 42篇 |
1986年 | 32篇 |
1985年 | 25篇 |
1984年 | 15篇 |
1983年 | 10篇 |
1982年 | 16篇 |
1981年 | 11篇 |
1980年 | 29篇 |
1979年 | 15篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1959年 | 8篇 |
1951年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Effects of different carbon sources and C/N values on nonvolatile taste components of Pleurotus eryngii 下载免费PDF全文
Wen Li Xiaobei Li Yan Yang Feng Zhou Yanfang Liu Shuai Zhou Hailong Yu 《International Journal of Food Science & Technology》2015,50(11):2360-2366
Pleurotus eryngii, the second largest industrial cultivation mushroom in China, is usually cultivated on substrates mainly consisting of sawdust and corncob. In this study, experiments were performed to determine the effects of different carbon sources and C/N values on nonvolatile taste components of P. eryngii. The effects of different carbon sources on nonvolatile taste components levels revealed that sawdust was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while corncob was beneficial to high contents of carbohydrate, polysaccharides and trehalose. At the similar C/N values, relatively higher sawdust content was beneficial to umami amino acid production, while relatively higher corncob content was beneficial to high contents of carbohydrate, polysaccharides and mannitol. Higher C/N value was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while lower C/N value was beneficial to high contents of carbohydrate, polysaccharides and trehalose. These results provided information for P. eryngii fruit body industrial cultivation to obtain specific nonvolatile taste components with high levels. 相似文献
2.
3.
4.
5.
段潇乐 《湖南工业职业技术学院学报》2015,(1):82-84
本研究检测了直接和间接两种修正性反馈与国内高职理科学生写作水平的关系。本实验持续五周,将150名学习者分为直接反馈组、间接反馈组及控制组,共安排了一次预先测试,,一次即时后测和一次延时后测,并分别对各组进行考察,结果显示两个实验组进步显著,且直接反馈效果最明显。 相似文献
6.
7.
通过分析攀长钢能源管理存在的不足和困难,从强化员工节能意识、合理组织生产、优化生产工艺、充分使用循环水、完善计量器具、加强余热利用及优化能源管理机制等方面入手提出节能改进措施,具有一定的现实意义。 相似文献
8.
Correlation between instrumental texture and colour quality attributes with sensory analysis of selected cheeses as affected by fat contents 下载免费PDF全文
A. Półtorak J. Wyrwisz M. Moczkowska M. Marcinkowska‐Lesiak A. Stelmasiak U. Ulanicka M. Zalewska A. Wierzbicka Da‐Wen Sun 《International Journal of Food Science & Technology》2015,50(4):999-1008
This study evaluated several physical and sensory parameters of different types of cheese available in the Polish market. The measurements of textural properties were conducted in an Instron universal testing machine, while the colour properties of cheeses were measured using a Minolta chromameter. The chemical composition was determined by means of the near‐infrared spectroscopy (NIRs). Moreover, a trained sensory panel was invited to assess the cheese texture‐related properties. Generally, cheeses with reduced fat content were characterised by higher hardness, adhesiveness, cohesiveness and elasticity. Texture‐related parameters of cheese with canola oil were comparable to that of most of full‐fat cheeses. The correlation analysis between physical and sensory attributes related to cheese textural properties indicated the potential applications of TPA, shear and penetration tests (r = 0.766, r = 0.75 and r = 0.765, respectively) for the evaluation of sensory properties related to the hardness. Meanwhile, the elasticity of cheese obtained from sensory evaluation was strongly correlated with the elasticity determined from the shear test (r = 0.722) and moderately correlated with the elasticity from penetration test (r = 0.588), indicating a need to refine the method of penetration test. In addition, cheeses exhibited higher meltability during convection heating at 230 °C than microwave heating. The values of meltability for cheese with reduced fat content were lower than those of full‐fat cheese. 相似文献
9.
10.