全文获取类型
收费全文 | 2293篇 |
免费 | 30篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 19篇 |
综合类 | 1篇 |
化学工业 | 243篇 |
金属工艺 | 1101篇 |
机械仪表 | 42篇 |
建筑科学 | 36篇 |
能源动力 | 56篇 |
轻工业 | 107篇 |
水利工程 | 14篇 |
石油天然气 | 3篇 |
无线电 | 151篇 |
一般工业技术 | 201篇 |
冶金工业 | 106篇 |
自动化技术 | 245篇 |
出版年
2023年 | 18篇 |
2022年 | 22篇 |
2021年 | 28篇 |
2020年 | 31篇 |
2019年 | 32篇 |
2018年 | 41篇 |
2017年 | 42篇 |
2016年 | 33篇 |
2015年 | 34篇 |
2014年 | 45篇 |
2013年 | 110篇 |
2012年 | 94篇 |
2011年 | 122篇 |
2010年 | 120篇 |
2009年 | 133篇 |
2008年 | 145篇 |
2007年 | 126篇 |
2006年 | 88篇 |
2005年 | 77篇 |
2004年 | 89篇 |
2003年 | 138篇 |
2002年 | 121篇 |
2001年 | 85篇 |
2000年 | 48篇 |
1999年 | 39篇 |
1998年 | 62篇 |
1997年 | 27篇 |
1996年 | 28篇 |
1995年 | 26篇 |
1994年 | 69篇 |
1993年 | 39篇 |
1992年 | 23篇 |
1991年 | 19篇 |
1990年 | 7篇 |
1989年 | 17篇 |
1988年 | 6篇 |
1987年 | 12篇 |
1986年 | 9篇 |
1985年 | 19篇 |
1984年 | 15篇 |
1983年 | 9篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1980年 | 8篇 |
1979年 | 9篇 |
1977年 | 6篇 |
1975年 | 5篇 |
1974年 | 7篇 |
1973年 | 7篇 |
1971年 | 4篇 |
排序方式: 共有2325条查询结果,搜索用时 0 毫秒
1.
M A Fennir J A Landry H S Ramaswamy V G S Raghavan 《The Journal of microwave power and electromagnetic energy》2003,38(3):189-196
This study investigates the effect of extraction methods on the color of date syrup and the potential use of microwave power for syrup processing. Sugar solutions were extracted from dates by boiling, soaking and blending. Color and sugar content of the extracted solutions were measured, and the percentage of sugar extracted form the total fruit sugar determined. Boiling was found to be the most efficient method of extraction whereby 74% of total samples sugar was extracted. In contrast, only 54.2% of fruit sugar was extracted by blending and 42% by soaking. In addition, solutions extracted by soaking and blending had a foaming problem in the subsequent concentration process. The extraction method had no effect on the product final color. The extracted solution was concentrated using two heating methods: conventional and microwave heating at a 600 W capacity and a frequency of 2450 MHz applied at three power levels: 10, 7, and 6. In the heating process, 180 minutes were needed to achieve a 77% degrees Brix using convective heating, while it took 81, 138, and 166 minutes of microwave heating at power level 10, 7, and 6, respectively to achieve the same concentration. Water activity of the syrup was measured within a sugar content range of 50 to 80% degrees Brix and the sugar concentration at which the product is shelf stable was determined at 76%. 相似文献
2.
N. M. Sanghavi Hema Venkatesh Varsha Tandel 《Drug development and industrial pharmacy》1994,20(7):1275-1283
Gilbenclamide, a widely used potent hypoglycaemic agent was solubllized using β -Cyclodextrin and β -Cyclodextrin derivatives. Complexes were prepared by kneading method in a molar ratio of 1:1 of the drug and the cyclodextrlns respectively. The Glibenclamide β -Cyelocextrin complex was characterized and evaluated by I.R. studies, Differential Scanning Calorimotry 6 X-ray diffractometry. The in-vitro dissolution rates of drug from inclusion complexes of β Cyclodextrins and its derivatives were compared. A significant Improvement In dissolution lor, rates of Gllbenclamide was observed with Inclusion complexes of all the Cyclodextrins. However, the solubilizing effect was more in case of β-Cyclodextrin derivatives. 相似文献
3.
4.
5.
6.
7.
8.
9.
Static network-related system voltage stability margin (VSM) depends on the availability of reactive power to support the transport of real power from sources to sinks. Based on this premise, the total VAr loss is minimized in the unified OPF framework considering real and reactive power controllers, and its effect on VSM is studied. Studies are conducted on a three-bus system, the IEEE 30-bus system, and a 191-bus Indian electric power system, and their results are reported. 相似文献
10.