全文获取类型
收费全文 | 6077篇 |
免费 | 263篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 69篇 |
综合类 | 6篇 |
化学工业 | 1320篇 |
金属工艺 | 142篇 |
机械仪表 | 102篇 |
建筑科学 | 345篇 |
矿业工程 | 10篇 |
能源动力 | 133篇 |
轻工业 | 691篇 |
水利工程 | 51篇 |
石油天然气 | 9篇 |
武器工业 | 1篇 |
无线电 | 453篇 |
一般工业技术 | 1054篇 |
冶金工业 | 1241篇 |
原子能技术 | 73篇 |
自动化技术 | 641篇 |
出版年
2023年 | 33篇 |
2022年 | 31篇 |
2021年 | 110篇 |
2020年 | 84篇 |
2019年 | 91篇 |
2018年 | 131篇 |
2017年 | 125篇 |
2016年 | 153篇 |
2015年 | 136篇 |
2014年 | 176篇 |
2013年 | 249篇 |
2012年 | 228篇 |
2011年 | 272篇 |
2010年 | 248篇 |
2009年 | 210篇 |
2008年 | 226篇 |
2007年 | 208篇 |
2006年 | 198篇 |
2005年 | 141篇 |
2004年 | 147篇 |
2003年 | 140篇 |
2002年 | 125篇 |
2001年 | 143篇 |
2000年 | 130篇 |
1999年 | 151篇 |
1998年 | 383篇 |
1997年 | 261篇 |
1996年 | 182篇 |
1995年 | 108篇 |
1994年 | 102篇 |
1993年 | 103篇 |
1992年 | 65篇 |
1991年 | 54篇 |
1990年 | 71篇 |
1989年 | 57篇 |
1988年 | 42篇 |
1987年 | 50篇 |
1986年 | 49篇 |
1985年 | 38篇 |
1984年 | 38篇 |
1983年 | 47篇 |
1982年 | 50篇 |
1981年 | 44篇 |
1980年 | 40篇 |
1979年 | 50篇 |
1978年 | 44篇 |
1977年 | 79篇 |
1976年 | 97篇 |
1975年 | 37篇 |
1966年 | 28篇 |
排序方式: 共有6341条查询结果,搜索用时 359 毫秒
1.
Moghadam Seyedeh Hadis Ashofteh Parisa-Sadat Loáiciga Hugo A. 《Water Resources Management》2022,36(9):3181-3205
Water Resources Management - The water evaluation and planning (WEAP) approach and the invasive weed optimization algorithm (IWOA) are herein employed to determine the optimal operating policies in... 相似文献
2.
3.
Andrés Aguirre Matías Cabruja Rodolfo Cabrera Florencia Eberhardt Salvador Peirú Hugo G. Menzella Rodolfo M. Rasia 《Journal of the American Oil Chemists' Society》2015,92(1):47-53
Steryl glucosides (SG) are common contaminants in biodiesel that form precipitates, which form and cause problems due to fouling during transport and storage. Therefore, their quantification is necessary to assess the quality of this fuel. The methods currently available for SG analysis require expensive instrumentation, need a previous concentration step by solid‐phase extraction (SPE) or are of limited use for the quantitative assessment. We developed an enzymatic method for SG quantification in biodiesel samples based on the hydrolysis of the glucoside catalyzed by a broadly specific beta glucosidase and the subsequent determination of the glucose released by the reaction. The method is non‐expensive, sensitive and was adapted to 96‐well format fluorescence plate reader, making it useful for the parallel assay of multiple samples. The enzymatic assay presented here represent a valuable tool for both quality control and the development of improved biodiesel production and purification procedures. 相似文献
4.
5.
High‐intensity sweeteners in espresso coffee: ideal and equivalent sweetness and time–intensity analysis 下载免费PDF全文
Bruna M. Azevedo Flávio L. Schmidt Helena M. A. Bolini 《International Journal of Food Science & Technology》2015,50(6):1374-1381
The efficient substitution of sucrose by a sweetener in beverages requires the application of some sensory techniques. First, one must determine the concentrations of the sweeteners under study, equivalent in sweetness to the ideal sucrose concentration. In addition, it is fundamental to determine which is most similar to sucrose. The objectives of this study were to determine the ideal sweetness for espresso coffee and the equivalent concentrations in sweetness of different sweeteners, as well as characterise the time–intensity profile of each sweetener in relation to sweetness. The sweeteners evaluated were sucralose, aspartame, neotame, a cyclamate/saccharin mixture (2:1) and stevia. The sucrose concentration considered ideal by consumers was 12.5% (w/v), and the equivalent concentrations of the sweeteners were 0.0159% for sucralose, 0.0549% for aspartame, 0.0016% for neotame, 0.0359% for the cyclamate/saccharin mixture and 0.0998% for stevia. The time–intensity analysis indicated that possibly the sweeteners neotame, aspartame and sucralose would be the best substitutes for sucrose. 相似文献
6.
7.
Hugo R. Fernandes Anuraag Gaddam Dilshat U. Tulyaganov José M. F. Ferreira 《International Journal of Applied Ceramic Technology》2020,17(1):64-74
Recycling has emerged as an environmental key point due to the diminishing of natural resources and the generation of ever-increasing amounts of industrial solid wastes. Glass wastes are among the materials that attract great interest in the recycling concept. This work presents the results of foams production from four series of compositions. The first series comprises powders of a sodium-calcium-silicate sheet glass cullet as the main component, an alkali-earth aluminosilicate glass as an additive, and a reagent grade silicon carbide (SiC) powder as gassing agent. In the second series, the glass cullet was used in combination with fly ashes (FLA) as main components, while SiC waste from abrasive paper served as foaming agent. In the third and fourth series, carbonates (calcite and dolomite) were used for foaming powder mixtures composed of sheet glass cullet and FLA, and powdered cathode ray tube panel glasses, respectively. All the processing parameters, including the main components, the nature and content of foaming agents are shown to play a crucial role on the foaming ability and final properties of the glass foams. 相似文献
8.
Freddy A. Bernal Dr. Marcel Kaiser Prof. Dr. Bernhard Wünsch Prof. Dr. Thomas J. Schmidt 《ChemMedChem》2020,15(1):68-78
Protozoal infections are still a global health problem, threatening the lives of millions of people around the world, mainly in impoverished tropical and sub-tropical regions. Thus, in view of the lack of efficient therapies and increasing resistances against existing drugs, this study describes the antiprotozoal potential of synthetic cinnamate ester analogues and their structure-activity relationships. In general, Leishmania donovani and Trypanosoma brucei were quite susceptible to the compounds in a structure-dependent manner. Detailed analysis revealed a key role of the substitution pattern on the aromatic ring and a marked effect of the side chain on the activity against these two parasites. The high antileishmanial potency and remarkable selectivity of the nitro-aromatic derivatives suggested them as promising candidates for further studies. On the other hand, the high in vitro potency of catechol-type compounds against T. brucei could not be extrapolated to an in vivo mouse model. 相似文献
9.
10.