全文获取类型
收费全文 | 1519546篇 |
免费 | 27552篇 |
国内免费 | 6997篇 |
专业分类
电工技术 | 34492篇 |
综合类 | 6386篇 |
化学工业 | 272180篇 |
金属工艺 | 64750篇 |
机械仪表 | 43356篇 |
建筑科学 | 46116篇 |
矿业工程 | 11497篇 |
能源动力 | 50387篇 |
轻工业 | 111863篇 |
水利工程 | 15490篇 |
石油天然气 | 37875篇 |
武器工业 | 132篇 |
无线电 | 197558篇 |
一般工业技术 | 287032篇 |
冶金工业 | 170864篇 |
原子能技术 | 34190篇 |
自动化技术 | 169927篇 |
出版年
2021年 | 15607篇 |
2020年 | 11893篇 |
2019年 | 14668篇 |
2018年 | 16916篇 |
2017年 | 16396篇 |
2016年 | 21884篇 |
2015年 | 17463篇 |
2014年 | 28740篇 |
2013年 | 87917篇 |
2012年 | 35900篇 |
2011年 | 49064篇 |
2010年 | 43413篇 |
2009年 | 51757篇 |
2008年 | 45360篇 |
2007年 | 42768篇 |
2006年 | 44604篇 |
2005年 | 39774篇 |
2004年 | 41723篇 |
2003年 | 41653篇 |
2002年 | 40488篇 |
2001年 | 37416篇 |
2000年 | 35829篇 |
1999年 | 35167篇 |
1998年 | 48060篇 |
1997年 | 40753篇 |
1996年 | 36254篇 |
1995年 | 31172篇 |
1994年 | 29158篇 |
1993年 | 29085篇 |
1992年 | 26156篇 |
1991年 | 23271篇 |
1990年 | 23646篇 |
1989年 | 22698篇 |
1988年 | 21209篇 |
1987年 | 19481篇 |
1986年 | 18837篇 |
1985年 | 22154篇 |
1984年 | 22329篇 |
1983年 | 20242篇 |
1982年 | 19235篇 |
1981年 | 19376篇 |
1980年 | 17948篇 |
1979年 | 18442篇 |
1978年 | 17704篇 |
1977年 | 17465篇 |
1976年 | 18383篇 |
1975年 | 15974篇 |
1974年 | 15464篇 |
1973年 | 15573篇 |
1972年 | 12990篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
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
12.
13.
14.
15.
Can Ercan S. Esra Safran Artuğ Türkmenoğlu Uğur Karabakal 《Journal of surfactants and detergents》2021,24(1):139-147
Garzan oil field is located at the south east of Turkey. It is a mature oil field and the reservoir is fractured carbonate reservoir. After producing about 1% original oil in place (OOIP) reservoir pressure started to decline. Waterflooding was started in order to support reservoir pressure and also to enhance oil production in 1960. Waterflooding improved the oil recovery but after years of flooding water breakthrough at the production wells was observed. This increased the water/oil ratio at the production wells. In order to enhance oil recovery again different techniques were investigated. Chemical enhanced oil recovery (EOR) methods are gaining attention all over the world for oil recovery. Surfactant injection is an effective way for interfacial tension (IFT) reduction and wettability reversal. In this study, 31 different types of chemicals were studied to specify the effects on oil production. This paper presents solubility of surfactants in brine, IFT and contact angle measurements, imbibition tests, and lastly core flooding experiments. Most of the chemicals were incompatible with Garzan formation water, which has high divalent ion concentration. In this case, the usage of 2-propanol as co-surfactant yielded successful results for stability of the selected chemical solutions. The results of the wettability test indicated that both tested cationic and anionic surfactants altered the wettability of the carbonate rock from oil-wet to intermediate-wet. The maximum oil recovery by imbibition test was reached when core was exposed 1-ethly ionic liquid after imbibition in formation water. Also, after core flooding test, it is concluded that considerable amount of oil can be recovered from Garzan reservoir by waterflooding alone if adverse effects of natural fractures could be eliminated. 相似文献
16.
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
17.
Vijay Singh Sharanagat Prabhat K. Nema Lochan Singh Ankur Kumar 《International Journal of Food Science & Technology》2022,57(3):1654-1665
The effect of microwave roasting parameters (300, 450 and 600 W; 5, 10 and 15 min) on acrylamide content in sorghum grain was determined using High Pressure Liquid Chromatography (HPLC)-photo diode array (PDA) detector coupled with C-18 column. Samples roasted at 300 and 450 W did not possess acrylamide, whereas 600 W (15 min) favoured formation of 2740.19 µg/kg of acrylamide, levels far exceeding the defined European Union (EU) limits. The chronic daily intake (CDI) for acrylamide through consumption of such grain flour was 3.25–9.5-fold higher to Joint FAO/WHO Expert Committee on Food Additives (JECFA) defined high exposure limits. The margin of exposure (MOE) values ranged from 4.3 to 12.76 and from 11.07 to 32.27 for neoplastic and neurological effects, respectively, demonstrating high exposure and serious health concerns associated with dietary intake of this toxicant. This study assesses the risk for the Indian population and highlights the importance of optimising process parameters for food product to minimise such exposure risks. 相似文献
18.
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
19.
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
20.