全文获取类型
收费全文 | 1416篇 |
免费 | 35篇 |
国内免费 | 28篇 |
专业分类
电工技术 | 40篇 |
综合类 | 62篇 |
化学工业 | 64篇 |
金属工艺 | 189篇 |
机械仪表 | 60篇 |
建筑科学 | 32篇 |
矿业工程 | 1篇 |
能源动力 | 16篇 |
轻工业 | 302篇 |
水利工程 | 6篇 |
石油天然气 | 1篇 |
无线电 | 56篇 |
一般工业技术 | 193篇 |
冶金工业 | 358篇 |
原子能技术 | 20篇 |
自动化技术 | 79篇 |
出版年
2023年 | 3篇 |
2022年 | 10篇 |
2021年 | 10篇 |
2020年 | 4篇 |
2019年 | 11篇 |
2018年 | 8篇 |
2017年 | 10篇 |
2016年 | 9篇 |
2015年 | 12篇 |
2014年 | 44篇 |
2013年 | 166篇 |
2012年 | 79篇 |
2011年 | 105篇 |
2010年 | 60篇 |
2009年 | 82篇 |
2008年 | 49篇 |
2007年 | 37篇 |
2006年 | 55篇 |
2005年 | 25篇 |
2004年 | 33篇 |
2003年 | 20篇 |
2002年 | 16篇 |
2001年 | 6篇 |
2000年 | 12篇 |
1999年 | 16篇 |
1998年 | 126篇 |
1997年 | 118篇 |
1996年 | 62篇 |
1995年 | 44篇 |
1994年 | 36篇 |
1993年 | 27篇 |
1992年 | 11篇 |
1991年 | 13篇 |
1990年 | 4篇 |
1989年 | 17篇 |
1988年 | 8篇 |
1987年 | 17篇 |
1986年 | 12篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 8篇 |
1982年 | 5篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 7篇 |
1977年 | 14篇 |
1976年 | 31篇 |
1975年 | 6篇 |
1967年 | 2篇 |
1960年 | 2篇 |
排序方式: 共有1479条查询结果,搜索用时 203 毫秒
1.
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
2.
After the remarkable increase of Internet users and broadband Internet subscribers at the end of the 20th century, the size of Korean Internet and e-commerce market steadily increased but the growth rate has been either stagnant or decreased. Trends of Korean Internet and e-commerce market are summarized in this paper the trends on Internet usage are introduced. Trends of online games, blogs and wireless Internet are introduced. The trends of Korean Internet market may have implications for China and Japan. 相似文献
3.
4.
5.
6.
7.
8.
Effects of oil droplets in an agar gel matrix were investigated by mechanical analyses and sensory evaluation. The results for compressive and puncture properties were expressed in terms of relative values. All compressive properties; stress, strain and compressive energy of emulsion gels, as obtained by compression tests, decreased with both increases of oil droplet size and oil volume fraction. The stress, strain and energy of the emulsion gels obtained by puncture tests did not change with an increase in oil droplet size. Results of sensory evaluation showed that the sample containing small oil droplets was harder than that with large oil droplets. On the other hand, the large oil droplet sample was oilier than that with small oil droplets. The sensory evaluations for hardness and oiliness of emulsion gels did not exhibit significant relations to most of the properties of mechanical analyses. 相似文献
9.
3H-labeled S. typhimurium cells inactivated by gamma-radiation (60Co) and by formaldehyde (5%) were used to determine if cell viability affected attachment to poultry skin. Both gamma-irradiated and formal-dehyde-treated cells attached like live cells. There was no difference in attachment between cells grown in a chemically defined medium (SCDM) or in brain heart infusion broth (BHI). Live and gamma-irradiated cells and BHI-grown and SCDM-grown cells had similar surface hydrophobicity. Live and gamma-irradiated cells had similar cell surface charges, whereas BHI and SCDM-grown cells had different surface charges. Differences in cell surface charge did not affect attachment rate. 相似文献
10.
MJ Prado AL Nicastri PL Costa T Rockman IL Tersariol HB Nader RT Barros EB Prado 《Canadian Metallurgical Quarterly》1997,30(7):865-872
The aim of the present study was to evaluate renal and liver distribution of two monoclonal immunoglobulin light chains. The chains were purified individually from the urine of patients with multiple myeloma and characterized as lambda light chains with a molecular mass of 28 kDa. They were named BJg (high amount of galactose residues exposed) and BJs (sialic acid residues exposed) on the basis of carbohydrate content. A scintigraphic study was performed on male Wistar rats weighing 250 g for 60 min after i.v. administration of 1 mg of each protein (7.4 MBq), as the intact proteins and also after carbohydrate oxidation. Images were obtained with a Siemens gamma camera with a high-resolution collimator and processed with a MicroDelta system. Hepatic and renal distribution were established and are reported as percent of injected dose. Liver uptake of BJg was significantly higher than liver uptake of BJs (94.3 vs 81.4%) (P < 0.05). This contributed to its greater removal from the intravascular compartment, and consequently lower kidney accumulation of BJg in comparison to BJs (5.7 vs 18.6%) (P < 0.05). After carbohydrate oxidation, there was a decrease in hepatic accumulation of both proteins and consequently a higher renal overload. The tissue distribution of periodate-treated BJg was similar to that of native BJs: 82.7 vs 81.4% in the liver and 17.3 vs 18.6% in the kidneys. These observations indicate the important role of sugar residues of Bence Jones proteins for their recognition by specific membrane receptors, which leads to differential tissue accumulation and possible toxicity. 相似文献