全文获取类型
收费全文 | 532516篇 |
免费 | 9648篇 |
国内免费 | 2361篇 |
专业分类
电工技术 | 9053篇 |
综合类 | 775篇 |
化学工业 | 81173篇 |
金属工艺 | 19626篇 |
机械仪表 | 17131篇 |
建筑科学 | 13057篇 |
矿业工程 | 2111篇 |
能源动力 | 14900篇 |
轻工业 | 49151篇 |
水利工程 | 4909篇 |
石油天然气 | 6795篇 |
武器工业 | 49篇 |
无线电 | 68218篇 |
一般工业技术 | 103385篇 |
冶金工业 | 94711篇 |
原子能技术 | 10593篇 |
自动化技术 | 48888篇 |
出版年
2021年 | 4948篇 |
2020年 | 3713篇 |
2019年 | 4376篇 |
2018年 | 6932篇 |
2017年 | 7041篇 |
2016年 | 7788篇 |
2015年 | 5495篇 |
2014年 | 9176篇 |
2013年 | 25145篇 |
2012年 | 15384篇 |
2011年 | 21054篇 |
2010年 | 16302篇 |
2009年 | 18353篇 |
2008年 | 18885篇 |
2007年 | 18406篇 |
2006年 | 16410篇 |
2005年 | 14946篇 |
2004年 | 14464篇 |
2003年 | 13995篇 |
2002年 | 13352篇 |
2001年 | 13373篇 |
2000年 | 12405篇 |
1999年 | 13088篇 |
1998年 | 31290篇 |
1997年 | 21984篇 |
1996年 | 16892篇 |
1995年 | 12895篇 |
1994年 | 11237篇 |
1993年 | 11141篇 |
1992年 | 8004篇 |
1991年 | 7636篇 |
1990年 | 7341篇 |
1989年 | 7140篇 |
1988年 | 6727篇 |
1987年 | 5796篇 |
1986年 | 5693篇 |
1985年 | 6585篇 |
1984年 | 5996篇 |
1983年 | 5490篇 |
1982年 | 5156篇 |
1981年 | 5160篇 |
1980年 | 4989篇 |
1979年 | 4653篇 |
1978年 | 4557篇 |
1977年 | 5143篇 |
1976年 | 6592篇 |
1975年 | 3867篇 |
1974年 | 3731篇 |
1973年 | 3799篇 |
1972年 | 3080篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Journal of Materials Science - 相似文献
2.
Ji Hye Yang Sae Kwang Ku IL Je Cho Je Hyeon Lee Chang-Su Na Sung Hwan Ki 《International journal of molecular sciences》2021,22(4)
Hepatic fibrosis occurs when liver tissue becomes scarred from repetitive liver injury and inflammatory responses; it can progress to cirrhosis and eventually to hepatocellular carcinoma. Previously, we reported that neoagarooligosaccharides (NAOs), produced by the hydrolysis of agar by β-agarases, have hepatoprotective effects against acetaminophen overdose-induced acute liver injury. However, the effect of NAOs on chronic liver injury, including hepatic fibrosis, has not yet been elucidated. Therefore, we examined whether NAOs protect against fibrogenesis in vitro and in vivo. NAOs ameliorated PAI-1, α-SMA, CTGF and fibronectin protein expression and decreased mRNA levels of fibrogenic genes in TGF-β-treated LX-2 cells. Furthermore, downstream of TGF-β, the Smad signaling pathway was inhibited by NAOs in LX-2 cells. Treatment with NAOs diminished the severity of hepatic injury, as evidenced by reduction in serum alanine aminotransferase and aspartate aminotransferase levels, in carbon tetrachloride (CCl4)-induced liver fibrosis mouse models. Moreover, NAOs markedly blocked histopathological changes and collagen accumulation, as shown by H&E and Sirius red staining, respectively. Finally, NAOs antagonized the CCl4-induced upregulation of the protein and mRNA levels of fibrogenic genes in the liver. In conclusion, our findings suggest that NAOs may be a promising candidate for the prevention and treatment of chronic liver injury via inhibition of the TGF-β/Smad signaling pathway. 相似文献
3.
Wireless Personal Communications - Chronic kidney disease (CKD) is a gradual loss of kidney function over the period of time and it is irrevocable once functionality reaches the critical state.... 相似文献
4.
Xiao Zhu Chen Yanxun Jiang Hongbo Hu Zhenzhen Lui John C. S. Min Geyong Dustdar Schahram 《Wireless Networks》2022,28(7):3305-3322
Wireless Networks - Unmanned aerial vehicles (UAV) have been widely used in various fields because of their high mobility and portability. At the same time, due to the rapid development of... 相似文献
5.
6.
7.
8.
Muniyandi Kasipandi Jagadeesan Gayathri George Blassan P. Manoharan Ashwini Lydia Nataraj Gayathri Abrahamse Heidi Thangaraj Parimelazhagan 《Food science and biotechnology》2022,31(13):1717-1728
Food Science and Biotechnology - A rich source of nutrients, figs have a number of clinically validated benefits. This study aimed to evaluate the in vitro simulated gastrointestinal digestion, and... 相似文献
9.
Multimedia Tools and Applications - In this work, a new fuzzy logic-based algorithm is proposed for the enhancement of low light color images. A generalization of a fuzzy set known as an... 相似文献
10.
Shin Hansub Sim Sungyong Kwon Hyukyoon Hwang Sangheum Lee Younho 《International Journal of Information Security》2022,21(1):25-36
International Journal of Information Security - This paper deals with a well-known problem in the area of the smudge attacks: when a user draws a pattern to unlock the pattern lock on a smartphone... 相似文献