全文获取类型
收费全文 | 39444篇 |
免费 | 4440篇 |
国内免费 | 2088篇 |
专业分类
电工技术 | 2888篇 |
技术理论 | 3篇 |
综合类 | 4744篇 |
化学工业 | 2040篇 |
金属工艺 | 720篇 |
机械仪表 | 1791篇 |
建筑科学 | 4499篇 |
矿业工程 | 1872篇 |
能源动力 | 1027篇 |
轻工业 | 6573篇 |
水利工程 | 2066篇 |
石油天然气 | 4167篇 |
武器工业 | 852篇 |
无线电 | 2401篇 |
一般工业技术 | 2463篇 |
冶金工业 | 1224篇 |
原子能技术 | 272篇 |
自动化技术 | 6370篇 |
出版年
2024年 | 256篇 |
2023年 | 664篇 |
2022年 | 1211篇 |
2021年 | 1455篇 |
2020年 | 1578篇 |
2019年 | 1288篇 |
2018年 | 1252篇 |
2017年 | 1318篇 |
2016年 | 1625篇 |
2015年 | 1677篇 |
2014年 | 2716篇 |
2013年 | 2391篇 |
2012年 | 3105篇 |
2011年 | 3191篇 |
2010年 | 2310篇 |
2009年 | 2381篇 |
2008年 | 2139篇 |
2007年 | 2570篇 |
2006年 | 2223篇 |
2005年 | 1984篇 |
2004年 | 1594篇 |
2003年 | 1336篇 |
2002年 | 992篇 |
2001年 | 856篇 |
2000年 | 660篇 |
1999年 | 560篇 |
1998年 | 422篇 |
1997年 | 405篇 |
1996年 | 343篇 |
1995年 | 280篇 |
1994年 | 230篇 |
1993年 | 185篇 |
1992年 | 136篇 |
1991年 | 109篇 |
1990年 | 78篇 |
1989年 | 87篇 |
1988年 | 38篇 |
1987年 | 35篇 |
1986年 | 33篇 |
1985年 | 22篇 |
1984年 | 29篇 |
1983年 | 29篇 |
1982年 | 16篇 |
1981年 | 14篇 |
1979年 | 13篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1964年 | 14篇 |
1963年 | 9篇 |
1959年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Quality enhancement of the abundant under‐valued crustacean,lobster krill (Munida spp.), during its chilled storage 下载免费PDF全文
Bibiana García‐Soto José M. Miranda Jorge Barros‐Velázquez Santiago P. Aubourg 《International Journal of Food Science & Technology》2015,50(3):708-716
Lobster krill (Munida genus) represents an under‐valued crustacean frequently caught on European fishing banks. In this work, its sensory, microbiological and biochemical qualities were evaluated during chilled storage. Additionally, the effects of a prestorage antimelanosic treatment consisting of soaking in sodium metabisulphite (SMB) solutions at two different concentrations (0.25% and 0.75%) were also studied. SMB prestorage treatment provided lobster specimens that still exhibited acceptable sensory quality after 10 days of storage, while control specimens were unacceptable at that time. SMB treatment also resulted in a significant (P < 0.05) inhibition of microbial growth, mainly of Enterobacteriaceae, psychrotrophes and proteolytic bacteria. Low lipid oxidation levels were observed for all batches; however, a significantly higher (P < 0.05) retention of polyunsaturated fatty acids was found in SMB‐treated lobster, especially in the 0.75% SMB batch. The results presented here open the way to the potential commercialisation of currently under‐utilised lobster krill as a chilled product. 相似文献
2.
Combination of heat treatment and chitosan coating to improve postharvest quality of wolfberry (Lycium barbarum) 下载免费PDF全文
Zhaojun Ban Wenwen Wei Xiangzheng Yang Jianhua Feng Junfeng Guan Li Li 《International Journal of Food Science & Technology》2015,50(4):1019-1025
The synergistic application of hot water dip at 42 °C for 30 min and 1% chitosan coating on differentiation in postharvest quality traits, microstructure as well as microbiological evolution of wolfberry fruits was investigated. Fresh wolfberry fruits were stored at 2 ± 0.5 °C and 90% relative humidity (RH) for 28 days. Results indicated the combination of prestorage heat treatment and chitosan coating maintained higher levels of ascorbic acid, total phenolic contents and antioxidant capacity as well as lower decay, compared with untreated wolfberry fruits. The possible mechanism was that the heat treatment almost sealed open stomata to limit the sites of pathogen penetration into fruits independently, followed by the biofilm formed by chitosan which controlled secondary infections as well as slowed changes in fruit respiration and metabolic activity in wolfberries. The synergistically treated fruit also exhibited a higher acceptability obtained by sensory analysis after cold storage. In this sense, the integrated application of heat treatment and chitosan coating could be regarded as an effective strategy to extend storage life and maintain the postharvest quality of wolfberry fruits. 相似文献
3.
4.
电网的安全水平主要取决于其使用产品的质量是否过关。如果产品的质量较好,则能建造出优质的电网,电网的安全水平便会随之提高。因此,应加强对产品质量的监督管理,从而提高电网的安全水平。我们可建立质量监督管理系统,及时抽检出质量不过关的产品,从而消除电网运行过程中潜在的安全隐患。 相似文献
5.
Effects of breed and age at slaughter on degradation of muscle lipids during processing of dry‐cured hams 下载免费PDF全文
Linda Storrustløkken Hanne Marie Devle Lars Erik Gangsei Carl Fredrik Naess‐Andresen Bjørg Egelandsdal Ole Alvseike Dag Ekeberg 《International Journal of Food Science & Technology》2015,50(8):1933-1943
Hams from Landrace, Duroc and Hampshire pigs slaughtered at ages 6, 7.5 and 9 months were processed to generate Norwegian Parma‐style hams. Lipid contents and the compositions of fatty acid classes (ΣSFA, ΣMUFA, ΣPUFA) within neutral lipids, phospholipids and free fatty acids were determined. Small differences in lipid degradation and composition of the classes were revealed. However, significant sensory differences related to lipids were observed. Breed was more important than age. Dry‐cured Hampshire hams gave a more intense mature odour that may be associated with higher overall lipid degradation. Unexpectedly, these hams also demonstrated high juiciness and tenderness, which could be related to the melting characteristics of the fat. Dry‐cured Duroc hams showed a higher susceptibility towards rancidity, presumably associated with preferential oxidation of n‐6 fatty acids relative to C18:1 n‐9. Dry‐cured Landrace hams showed the lowest juiciness and tenderness, likely due to their lower fat content (marbling). 相似文献
6.
7.
8.
孙洪松 《石油化工管理干部学院学报》2006,(1):52-55
目前,我国股票市场上的股票评级尚处于探索阶段,评级时多采用专家法或历史法,而对于影响股票评级的各因素的确定以及因素间的相互作用缺乏定量分析。研究将结构模型应用到我国股票市场的股票评级中,建立关于我国股票评级的财务结构模型;分析各个因素对股票评级的影响;建立股票评级经验模式值。 相似文献
9.
10.
高抗挤厚壁套管的性能及应用效果评价 总被引:1,自引:1,他引:0
中原油田套管损坏的主要原因是现有套管强度不够,无法抵抗盐膏层段的巨大外挤力。开发了TP130TT型高抗挤厚壁套管,其强度能很好地抵抗盐膏层巨大外挤力。实验室试验表明,各项性能指标达到了设计要求,现场使用取得了很好的效果,解决了中原油田盐膏层段套管强度不足的难题。 相似文献