全文获取类型
收费全文 | 293956篇 |
免费 | 17535篇 |
国内免费 | 659篇 |
专业分类
电工技术 | 4553篇 |
综合类 | 286篇 |
化学工业 | 60000篇 |
金属工艺 | 11552篇 |
机械仪表 | 8660篇 |
建筑科学 | 7358篇 |
矿业工程 | 2279篇 |
能源动力 | 7013篇 |
轻工业 | 28579篇 |
水利工程 | 3671篇 |
石油天然气 | 8090篇 |
武器工业 | 26篇 |
无线电 | 30167篇 |
一般工业技术 | 63708篇 |
冶金工业 | 43456篇 |
原子能技术 | 6932篇 |
自动化技术 | 25820篇 |
出版年
2022年 | 2642篇 |
2021年 | 4066篇 |
2020年 | 4078篇 |
2019年 | 6255篇 |
2018年 | 8223篇 |
2017年 | 8508篇 |
2016年 | 9432篇 |
2015年 | 7188篇 |
2014年 | 9245篇 |
2013年 | 17338篇 |
2012年 | 11363篇 |
2011年 | 12890篇 |
2010年 | 10922篇 |
2009年 | 11396篇 |
2008年 | 10847篇 |
2007年 | 10269篇 |
2006年 | 8751篇 |
2005年 | 7761篇 |
2004年 | 7137篇 |
2003年 | 7006篇 |
2002年 | 6576篇 |
2001年 | 6269篇 |
2000年 | 5894篇 |
1999年 | 5364篇 |
1998年 | 13209篇 |
1997年 | 9194篇 |
1996年 | 6878篇 |
1995年 | 4916篇 |
1994年 | 4270篇 |
1993年 | 4451篇 |
1992年 | 3233篇 |
1991年 | 3222篇 |
1990年 | 3053篇 |
1989年 | 3060篇 |
1988年 | 3055篇 |
1987年 | 2689篇 |
1986年 | 2718篇 |
1985年 | 3042篇 |
1984年 | 2835篇 |
1983年 | 2669篇 |
1982年 | 2409篇 |
1981年 | 2390篇 |
1980年 | 2484篇 |
1979年 | 2425篇 |
1978年 | 2447篇 |
1977年 | 2695篇 |
1976年 | 3260篇 |
1975年 | 2247篇 |
1974年 | 2119篇 |
1973年 | 2244篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
82.
83.
84.
Physical Stability of Octenyl Succinate–Modified Polysaccharides and Whey Proteins for Potential Use as Bioactive Carriers in Food Systems 下载免费PDF全文
The high cost and potential toxicity of biodegradable polymers like poly(lactic‐co‐glycolic)acid (PLGA) has increased the interest in natural and modified biopolymers as bioactive carriers. This study characterized the physical stability (water sorption and state transition behavior) of selected starch and proteins: octenyl succinate–modified depolymerized waxy corn starch (DWxCn), waxy rice starch (DWxRc), phytoglycogen, whey protein concentrate (80%, WPC), whey protein isolate (WPI), and α‐lactalbumin (α‐L) to determine their potential as carriers of bioactive compounds under different environmental conditions. After enzyme modification and particle size characterization, glass transition temperature and moisture isotherms were used to characterize the systems. DWxCn and DWxRc had increased water sorption compared to native starch. The level of octenyl succinate anhydrate (OSA) modification (3% and 7%) did not reduce the water sorption of the DWxCn and phytoglycogen samples. The Guggenheim–Andersen–de Boer model indicated that native waxy corn had significantly (P < 0.05) higher water monolayer capacity followed by 3%‐OSA‐modified DWxCn, WPI, 3%‐OSA‐modified DWxRc, α‐L, and native phytoglycogen. WPC had significantly lower water monolayer capacity. All Tg values matched with the solid‐like appearance of the biopolymers. Native polysaccharides and whey proteins had higher glass transition temperature (Tg) values. On the other hand, depolymerized waxy starches at 7%‐OSA modification had a “melted” appearance when exposed to environments with high relative humidity (above 70%) after 10 days at 23 °C. The use of depolymerized and OSA‐modified polysaccharides blended with proteins created more stable blends of biopolymers. Hence, this biopolymer would be suitable for materials exposed to high humidity environments in food applications. 相似文献
85.
86.
87.
88.
89.
This paper considers a novel distributed iterative learning consensus control algorithm based on neural networks for the control of heterogeneous nonlinear multiagent systems. The system's unknown nonlinear function is approximated by suitable neural networks; the approximation error is countered by a robust term in the control. Two types of control algorithms, both of which utilize distributed learning laws, are provided to achieve consensus. In the provided control algorithms, the desired reference is considered to be an unknown factor and then estimated using the associated learning laws. The consensus convergence is proven by the composite energy function method. A numerical simulation is ultimately presented to demonstrate the efficacy of the proposed control schemes. 相似文献
90.
L. S. Belevskii N. V. Koptseva I. V. Belevskaya Yu. Yu. Efimova 《Russian Metallurgy (Metally)》2015,2015(9):753-758
The microstructure and properties of the functional coatings formed by impact friction processing of product surfaces with a flexible tool are studied. It is established that the processing produces a hard nanostructured surface layer with fragments up to 0.13 µm in size, as it is achieved by severe plastic deformation. 相似文献