全文获取类型
收费全文 | 6430篇 |
免费 | 93篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 33篇 |
综合类 | 2篇 |
化学工业 | 452篇 |
金属工艺 | 103篇 |
机械仪表 | 50篇 |
建筑科学 | 142篇 |
矿业工程 | 12篇 |
能源动力 | 61篇 |
轻工业 | 374篇 |
水利工程 | 41篇 |
石油天然气 | 12篇 |
无线电 | 197篇 |
一般工业技术 | 418篇 |
冶金工业 | 4313篇 |
原子能技术 | 41篇 |
自动化技术 | 273篇 |
出版年
2022年 | 45篇 |
2021年 | 49篇 |
2020年 | 39篇 |
2019年 | 48篇 |
2018年 | 51篇 |
2017年 | 45篇 |
2016年 | 50篇 |
2015年 | 53篇 |
2014年 | 57篇 |
2013年 | 138篇 |
2012年 | 104篇 |
2011年 | 155篇 |
2010年 | 130篇 |
2009年 | 135篇 |
2008年 | 159篇 |
2007年 | 116篇 |
2006年 | 117篇 |
2005年 | 108篇 |
2004年 | 89篇 |
2003年 | 81篇 |
2002年 | 94篇 |
2001年 | 59篇 |
2000年 | 71篇 |
1999年 | 167篇 |
1998年 | 1321篇 |
1997年 | 745篇 |
1996年 | 502篇 |
1995年 | 272篇 |
1994年 | 223篇 |
1993年 | 260篇 |
1992年 | 49篇 |
1991年 | 71篇 |
1990年 | 89篇 |
1989年 | 61篇 |
1988年 | 59篇 |
1987年 | 62篇 |
1986年 | 46篇 |
1985年 | 42篇 |
1984年 | 25篇 |
1983年 | 24篇 |
1982年 | 20篇 |
1981年 | 28篇 |
1980年 | 51篇 |
1979年 | 13篇 |
1978年 | 16篇 |
1977年 | 107篇 |
1976年 | 179篇 |
1975年 | 10篇 |
1973年 | 10篇 |
1972年 | 11篇 |
排序方式: 共有6524条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
Effect of pretreatments and freezing rate on the firmness of potato tissue after a freeze–thaw cycle
Sergio Carbonell Jorge C. Oliveira & Alan L. Kelly 《International Journal of Food Science & Technology》2006,41(7):757-767
The texture of potato tissue after a freeze–thaw process using different freezing rates and different pretreatments was analysed, in order to select the best strategy for optimum preservation of the textural characteristics of pre‐frozen potato. Ten blanching conditions were tested and a two‐step blanching process with calcium chloride (0.07 g mL?1) proved the most effective in protecting the tissue after a freeze–thaw process (maximum load force around 10–55% of the raw tissue, depending on potato batch, for air‐blast freezing and 20–60% for immersion freezing). Vacuum impregnation at 100 and 400 mbar, even when followed by different pre‐drying treatments to remove excess water, was very detrimental to resistance to a freeze–thaw process (maximum load force below 10% of the raw tissue for air‐blast freezing and below 20% for immersion freezing). Microstructure analysis confirmed better tissue integrity retention with ethyleneglycol immersion freezing instead of air‐freezing. Differences were found between batches with a 6‐month difference in storage time, indicating that the fresher batch was more suitable for freezing. 相似文献
7.
8.
M Kelly 《Canadian Metallurgical Quarterly》1996,17(2):60-62
Based on his experience with treatment of 112 children the author considers that severe and various disturbances of the rectum abturative apparatus function arising from surgical interventions in the anorectal area require the differentiated approach to choice of the method of surgical correction of the incontinence. The transplantation of the denervated muscle, transplantation of the vascular-nervous thoraco-dorsal flap, a lavsan band were used to make a pubo-rectal loop, plasty of the outer and inner sphincters being performed mainly with local tissues. 相似文献
9.
In response to D. Cicchetti's (see record 1998-01884-002) and W. A. Mason's (see record 1998-01884-003) commentaries, this article scrutinizes infant maltreatment in monkeys and its public health implications. Studies of infant abuse and neglect in monkeys have used operational definitions based on (a) adult behavior or (b) adult behavior and infant outcome (depending on data available for analysis). Direct comparisons between the incidence of maltreatment in monkey and human populations can be only tentative as a result of differences in operational definitions of maltreatment. A simplified version of the ecological-transactional model of maltreatment can be used in research with nonhuman primates, and different species can be used to model different aspects of the human phenomenon. Although abuse and neglect take different forms in animals and humans, research with animal models can make an important contribution to elucidating the adaptive function, if any, of child maltreatment and the proximate mechanisms underlying its occurrence. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
T. R. Guilinger M. J. Kelly J. R. Scully T. M. Christensen D. Ingersoll J. A. Knapp R. I. Ewing W. H. Casey S. S. Tsao 《Journal of Fusion Energy》1990,9(3):299-304
We describe several electrochemical methods used to investigate the possibility of cold fusion phenomena in palladium and titanium tritide cathodes. We performed long-term (up to 77 days) electrolysis experiments with electrochemical cells of the University of Utah type at current densities as high as 1 A/cm2, while monitoring neutron and tritium levels. With some cells, we pulsed the current to determine if neutron bursts would result. In another cell, we used titanium tritide as the cathode to determine if D-T reactions yielding neutrons would occur. In no instance were levels of neutrons or tritium significantly above background except in the titanium tritide cell where isotopic exchange, occcurring between the electrode and the electrolyte, resulted in significant tritium levels. We also combined x-ray photoelectron spectroscopy (XPS) and electrochemical hydrogen permeation experiments to determine the effectiveness of various Pd surface treatment procedures on the resultant electrochemical hydrogen absorption efficiency. Electroanalytical and thermal desorption/gas analysis techniques indicated the maximum loading of H in Pd was to a ratio of HPd=0.8. 相似文献