全文获取类型
收费全文 | 793189篇 |
免费 | 10898篇 |
国内免费 | 1677篇 |
专业分类
电工技术 | 14955篇 |
综合类 | 1035篇 |
化学工业 | 125256篇 |
金属工艺 | 30605篇 |
机械仪表 | 24756篇 |
建筑科学 | 18987篇 |
矿业工程 | 4921篇 |
能源动力 | 21180篇 |
轻工业 | 67844篇 |
水利工程 | 8879篇 |
石油天然气 | 16884篇 |
武器工业 | 47篇 |
无线电 | 88542篇 |
一般工业技术 | 157125篇 |
冶金工业 | 138780篇 |
原子能技术 | 17970篇 |
自动化技术 | 67998篇 |
出版年
2021年 | 7824篇 |
2020年 | 5896篇 |
2019年 | 7409篇 |
2018年 | 12292篇 |
2017年 | 12282篇 |
2016年 | 12771篇 |
2015年 | 8184篇 |
2014年 | 13729篇 |
2013年 | 37277篇 |
2012年 | 21257篇 |
2011年 | 28563篇 |
2010年 | 22697篇 |
2009年 | 25227篇 |
2008年 | 25632篇 |
2007年 | 25425篇 |
2006年 | 22081篇 |
2005年 | 20117篇 |
2004年 | 19385篇 |
2003年 | 18875篇 |
2002年 | 18229篇 |
2001年 | 17971篇 |
2000年 | 17244篇 |
1999年 | 17337篇 |
1998年 | 40609篇 |
1997年 | 29414篇 |
1996年 | 22985篇 |
1995年 | 17683篇 |
1994年 | 16061篇 |
1993年 | 15720篇 |
1992年 | 12140篇 |
1991年 | 11618篇 |
1990年 | 11521篇 |
1989年 | 11257篇 |
1988年 | 10853篇 |
1987年 | 9589篇 |
1986年 | 9493篇 |
1985年 | 10905篇 |
1984年 | 9861篇 |
1983年 | 9371篇 |
1982年 | 8456篇 |
1981年 | 8700篇 |
1980年 | 8197篇 |
1979年 | 8281篇 |
1978年 | 8055篇 |
1977年 | 9077篇 |
1976年 | 11523篇 |
1975年 | 7173篇 |
1974年 | 6850篇 |
1973年 | 6991篇 |
1972年 | 5930篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Semiconductors - In this work, we discuss for the first time the principle of rotation in the constant electric field of a conducting particle with participation of the Lorentz force, which ensures... 相似文献
4.
Atomic Energy - The history and direction of further development of space nuclear energetics are examined. The functional diagram and principle of operation of a promising, powerful,... 相似文献
5.
6.
Eivazzadeh-Keihan Reza Noruzi Ehsan Bahojb Mehrban Sarah Fattahi Aliabadi Hooman Aghamirza Moghim Karimi Meghdad Mohammadi Adibeh Maleki Ali Mahdavi Mohammad Larijani Bagher Shalan Ahmed Esmail 《Journal of Materials Science》2022,57(6):3855-3891
Journal of Materials Science - Chitosan is one of the natural cationic polymers with unique properties such as non-toxicity, biodegradability, biocompatibility, environmentally friendly that has... 相似文献
7.
Muhammad Yazid Samatra Nor Qhairul Izzreen Mohd Noor Umi Hartina Mohamad Razali Jamilah Bakar Sharifudin Md. Shaarani 《Comprehensive Reviews in Food Science and Food Safety》2022,21(4):3153-3176
Gelatin is one of the most important multifunctional biopolymers and is widely used as an essential ingredient in food, pharmaceutical, and cosmetics. Porcine gelatin is regarded as the leading source of gelatin globally then followed by bovine gelatin. Porcine sources are favored over other sources since they are less expensive. However, porcine gelatin is religiously prohibited to be consumed by Muslims and the Jewish community. It is predicted that the global demand for gelatin will increase significantly in the future. Therefore, a sustainable source of gelatin with efficient production and free of disease transmission must be developed. The highest quality of Bovidae-based gelatin (BG) was acquired through alkaline pretreatment, which displayed excellent physicochemical and rheological properties. The utilization of mammalian- and plant-based enzyme significantly increased the gelatin yield. The emulsifying and foaming properties of BG also showed good stability when incorporated into food and pharmaceutical products. Manipulation of extraction conditions has enabled the development of custom-made gelatin with desired properties. This review highlighted the various modifications of extraction and processing methods to improve the physicochemical and functional properties of Bovidae-based gelatin. An in-depth analysis of the crucial stage of collagen breakdown is also discussed, which involved acid, alkaline, and enzyme pretreatment, respectively. In addition, the unique characteristics and primary qualities of BG including protein content, amphoteric property, gel strength, emulsifying and viscosity properties, and foaming ability were presented. Finally, the applications and prospects of BG as the preferred gelatin source globally were outlined. 相似文献
8.
Journal of Computer and Systems Sciences International - It is shown that the Lyapunov theorem on the distribution properties of the sum of random variables with different distribution densities... 相似文献
9.
Kuznetsov Yu. A. Markov M. A. Kravchenko I. N. Krasikov A. V. Bykova A. D. 《Refractories and Industrial Ceramics》2021,62(4):421-425
Refractories and Industrial Ceramics - The paper introduces a promising technology for utilizing a traditional scheme for implementing a flow-through micro-arc oxidation method to restore localized... 相似文献
10.
Chumakov Yu. A. Knyazeva A. G. Pribytkov G. A. 《Theoretical Foundations of Chemical Engineering》2021,55(3):490-503
Theoretical Foundations of Chemical Engineering - On the basis of the classic concepts of the theory of solid-phase combustion, for the first time, a model with a detailed scheme of chemical... 相似文献