全文获取类型
收费全文 | 29269篇 |
免费 | 2490篇 |
国内免费 | 1201篇 |
专业分类
电工技术 | 1218篇 |
综合类 | 1579篇 |
化学工业 | 10130篇 |
金属工艺 | 2128篇 |
机械仪表 | 734篇 |
建筑科学 | 1123篇 |
矿业工程 | 582篇 |
能源动力 | 372篇 |
轻工业 | 5374篇 |
水利工程 | 95篇 |
石油天然气 | 925篇 |
武器工业 | 118篇 |
无线电 | 1758篇 |
一般工业技术 | 2994篇 |
冶金工业 | 1111篇 |
原子能技术 | 527篇 |
自动化技术 | 2192篇 |
出版年
2024年 | 126篇 |
2023年 | 446篇 |
2022年 | 941篇 |
2021年 | 1056篇 |
2020年 | 982篇 |
2019年 | 855篇 |
2018年 | 727篇 |
2017年 | 886篇 |
2016年 | 1030篇 |
2015年 | 1008篇 |
2014年 | 1451篇 |
2013年 | 1800篇 |
2012年 | 1916篇 |
2011年 | 2133篇 |
2010年 | 1596篇 |
2009年 | 1656篇 |
2008年 | 1483篇 |
2007年 | 1818篇 |
2006年 | 1775篇 |
2005年 | 1412篇 |
2004年 | 1172篇 |
2003年 | 1016篇 |
2002年 | 907篇 |
2001年 | 720篇 |
2000年 | 641篇 |
1999年 | 529篇 |
1998年 | 425篇 |
1997年 | 319篇 |
1996年 | 280篇 |
1995年 | 211篇 |
1994年 | 182篇 |
1993年 | 200篇 |
1992年 | 156篇 |
1991年 | 139篇 |
1990年 | 112篇 |
1989年 | 92篇 |
1988年 | 74篇 |
1987年 | 59篇 |
1986年 | 67篇 |
1985年 | 79篇 |
1984年 | 60篇 |
1983年 | 49篇 |
1982年 | 45篇 |
1981年 | 38篇 |
1980年 | 46篇 |
1978年 | 35篇 |
1977年 | 40篇 |
1976年 | 46篇 |
1975年 | 48篇 |
1974年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
吴正太 《精细石油化工进展》2007,8(6):42-46
采用中石化金陵分公司研究院研制的CI-50(Pd/丝光沸石)作C5/C6烷烃异构化催化剂.详细介绍了该催化剂的工业放大试验装置的工艺流程、首次开工过程中技术问题及处理方法. 相似文献
102.
Reports an error in "Does reward increase or decrease creativity" by Robert Eisenberger and Michael Selbst (Journal of Personality and Social Psychology, 1994[Jun], Vol 66[6], 1116-1127). In the aforementioned article, Figures 1 and 2 were interchanged. The figures appear with their correct captions in the erratum. (The following abstract of the original article appeared in record 1994-40652-001.) Two studies involving 504 school children investigated why behaviorists and cognitively oriented investigators have come to opposite conclusions about reward's effects on creativity. A monetary reward for a high degree of divergent thought in 1 task (word construction) increased children's subsequent originality in a different task (picture drawing). The same reward, made contingent on a low degree of divergent thought, reduced this generalized originality. These effects were eliminated by using a large reward and were restored by keeping the large reward out of the children's sight. The results suggest that reward training increases generalized creativity when (1) a high degree of divergent thought is required and (2) the reward is presented in not too salient a fashion. The findings are consistent with a 2-factor interpretation of rewarded creativity effects that incorporates learned industriousness and selective attention. [A correction concerning this article appears in Journal of Personality & Social Psychology, 1994(Jul), Vol 67(1), 125. Figures 1 and 2 were interchanged.] (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
103.
B.M. Naveena A.R. Sen M. Muthukumar S. Vaithiyanathan Y. Babji 《Journal of food science》2006,71(9):S603-S608
ABSTRACT: The aim of this study was to determine the effect of adding 3.3% sodium lactate (SL), 0.25% calcium lactate (CL), and 1.65% SL along with 0.125% CL (SL+CL) on the physicochemical properties, cooking characteristics, and microbiological quality of microwave-cooked chicken patties compared to control (no added lactates). The addition of lactates did not affect the proximate composition of cooked chicken patties. The pH of CL- or SL+CL-containing patties was significantly ( P < 0.05) reduced compared to control or SL patties. The SL-containing patties had lower ( P < 0.05) a w values compared to control or CL patties. The CL- or SL+CL-containing patties had lower denatured myoglobin and higher ( P < 0.05) cooking yield, surface redness (CIE a *), and chroma values. However, addition of CL alone resulted in higher total expressible fluid, indicating lower water-holding capacity. The CL-containing patties exhibited lower Warner–Bratzler shear force values and higher ( P < 0.05) penetrometer reading compared to the SL-containing patties, indicating soft texture. Thiobarbituric acid (TBA) values were significantly ( P < 0.05) reduced in all lactate-containing patties compared to control up to the 7th day of refrigerated storage under aerobic conditions. No difference ( P > 0.05) was observed in aerobic plate counts between control and lactate-added patties during 28-d storage. 相似文献
104.
Achu is a thick porridge obtained by cooking and pounding taro (Colocasia esculenta) corms and cormels in a mortar. This study was undertaken with the objective of producing precooked taro flour that can be used in the preparation of achu. Taro slices were precooked to times of 0, 20, 45 and 90 min and dried in an air convection oven at varying temperatures of 50, 60, 70 or 80 °C before milling into flour which was then analysed for its water absorption capacity (WAC), water solubility index, emulsion activity and stability, bulk density, foam capacity and least gelation concentration (LGC). Achu made from the flours were equally analysed for their relative penetrometric index, bulk density and colour. The results showed that precooking induced significant (P<0.05) decrease in foam capacity, penetrometric index, and increase in LGC, emulsion stability and WAC. The drying temperature also induces significant reduction in emulsion capacity and stability, penetrometric index, and increase in LGC, WAC. Long precooking time (>45 min) and drying temperature (>60 °C) induced significant reduction of the in-vitro carbohydrate digestibility of taro achu. 相似文献
105.
106.
107.
T. RONALD A. MAGEE CAROLE P.D. WILKINSON 《International Journal of Food Science & Technology》1992,27(5):541-549
Investigation of the effects of varying air velocity, slice thickness, and pre-treatment with sodium chloride solutions and surface active agents on drying potato slices indicated that the drying occurred entirely in the falling rate period and was controlled by the mechanism of liquid diffusion. The rate of drying, and therefore the diffusion coefficients, increased with the addition of sodium chloride and surface active agents. Diffusion coefficients were also influenced by air velocity and slice thickness, suggesting that the rate of drying of potato slices is controlled by a combination of internal and external resistances. 相似文献
108.
本文研究了LF6铝合金的超塑性/扩散连接组合工艺,用变形和再结晶的方法细化晶粒,成功地进行了SPF/DB工艺试验,利用电子探针观察了扩散连接接头的界面微观区域,并从机理上分析了金属的超塑性/扩散连接两种工艺之间的内部联系及其金属学行为。 相似文献
109.
所提出的磁光旋转器是由Verdet常数小的普通ZF-6小玻璃片和带有窄缝隙的小电磁铁组成,当电磁铁线圈的功耗为10W时,可得到21°的法拉第旋转。 相似文献
110.