全文获取类型
收费全文 | 181789篇 |
免费 | 19500篇 |
国内免费 | 12684篇 |
专业分类
电工技术 | 14552篇 |
技术理论 | 9篇 |
综合类 | 17454篇 |
化学工业 | 24860篇 |
金属工艺 | 11662篇 |
机械仪表 | 12272篇 |
建筑科学 | 13973篇 |
矿业工程 | 5848篇 |
能源动力 | 4759篇 |
轻工业 | 19093篇 |
水利工程 | 5155篇 |
石油天然气 | 8153篇 |
武器工业 | 2159篇 |
无线电 | 19595篇 |
一般工业技术 | 17590篇 |
冶金工业 | 8004篇 |
原子能技术 | 2715篇 |
自动化技术 | 26120篇 |
出版年
2024年 | 1023篇 |
2023年 | 3047篇 |
2022年 | 6658篇 |
2021年 | 8523篇 |
2020年 | 6244篇 |
2019年 | 4686篇 |
2018年 | 5020篇 |
2017年 | 5936篇 |
2016年 | 5140篇 |
2015年 | 7889篇 |
2014年 | 9970篇 |
2013年 | 11597篇 |
2012年 | 14094篇 |
2011年 | 15125篇 |
2010年 | 14170篇 |
2009年 | 13190篇 |
2008年 | 13509篇 |
2007年 | 12736篇 |
2006年 | 11595篇 |
2005年 | 9269篇 |
2004年 | 6546篇 |
2003年 | 5032篇 |
2002年 | 4992篇 |
2001年 | 4288篇 |
2000年 | 3512篇 |
1999年 | 2365篇 |
1998年 | 1718篇 |
1997年 | 1239篇 |
1996年 | 1076篇 |
1995年 | 799篇 |
1994年 | 645篇 |
1993年 | 485篇 |
1992年 | 382篇 |
1991年 | 291篇 |
1990年 | 215篇 |
1989年 | 212篇 |
1988年 | 118篇 |
1987年 | 100篇 |
1986年 | 83篇 |
1985年 | 47篇 |
1984年 | 23篇 |
1983年 | 32篇 |
1982年 | 35篇 |
1981年 | 43篇 |
1980年 | 59篇 |
1979年 | 26篇 |
1977年 | 44篇 |
1976年 | 83篇 |
1959年 | 21篇 |
1951年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Requirements Engineering - In software reuse, the reuse of UML class diagram produced in design phase has received more attention due to the important influence on the following developing process.... 相似文献
13.
Effects of different carbon sources and C/N values on nonvolatile taste components of Pleurotus eryngii
下载免费PDF全文
![点击此处可从《International Journal of Food Science & Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
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
14.
15.
Xiaohui Hu Li Cheng Yan Hong Zhaofeng Li Caiming Li Zhengbiao Gu 《International Journal of Food Science & Technology》2021,56(8):4149-4158
Incorporating high level of potato flour into wheat flour enhances nutritional values of bread but induces a series of problems that lead to the decline of the bread quality. To overcome the barrier, wheat gluten and carboxymethylcellulose (CMC) were added into potato–wheat composite flour to improve dough machinability and bread quality. The rheological properties, thermo-mechanical properties and microstructures of dough were investigated. The results showed that the interaction between gluten and CMC mitigated the discontinuity of gluten matrix and gluten protein aggregation caused by the addition of potato flour, which yielded a more branched and compact gluten network. The compact three-dimensional viscoelastic structure induced improvements of gas retention capacity and dough stability, making it mimic the machinability properties of wheat flour dough. Bread qualities were apparently improved with the combined use of 4% gluten and 6% CMC, of which specific volume increased by 42.86%, and simultaneously, hardness reduced by 75.93%. 相似文献
16.
17.
18.
Private information retrieval(PIR) is an important privacy protection issue of secure multi-party computation, but the PIR protocols based on classical cryptography are vulnerable because of new technologies,such as quantum computing and cloud computing. The quantum private queries(QPQ) protocols available, however, has a high complexity and is inefficient in the face of large database. This paper, based on the QKD technology which is mature now, proposes a novel QPQ protocol utilizing the key dilution and auxiliary parameter. Only N quits are required to be sent in the quantum channel to generate the raw key, then the straight k bits in the raw key are added bitwise to dilute the raw key, and a final key is consequently obtained to encrypt the database. By flexible adjusting of auxiliary parameters θ and k, privacy is secured and the query success ratio is improved. Feasibility and performance analyses indicate that the protocol has a high success ratio in first-trial query and is easy to implement, and that the communication complexity of O(N) is achieved. 相似文献
19.
20.
Ionomics is a novel multidisciplinary field that uses advanced techniques to investigate the composition and distribution of all minerals and trace elements in a living organism and their variations under diverse physiological and pathological conditions. It involves both high-throughput elemental profiling technologies and bioinformatic methods, providing opportunities to study the molecular mechanism underlying the metabolism, homeostasis, and cross-talk of these elements. While much effort has been made in exploring the ionomic traits relating to plant physiology and nutrition, the use of ionomics in the research of serious diseases is still in progress. In recent years, a number of ionomic studies have been carried out for a variety of complex diseases, which offer theoretical and practical insights into the etiology, early diagnosis, prognosis, and therapy of them. This review aims to give an overview of recent applications of ionomics in the study of complex diseases and discuss the latest advances and future trends in this area. Overall, disease ionomics may provide substantial information for systematic understanding of the properties of the elements and the dynamic network of elements involved in the onset and development of diseases. 相似文献