全文获取类型
收费全文 | 4438篇 |
免费 | 727篇 |
国内免费 | 475篇 |
专业分类
电工技术 | 482篇 |
综合类 | 468篇 |
化学工业 | 429篇 |
金属工艺 | 119篇 |
机械仪表 | 308篇 |
建筑科学 | 236篇 |
矿业工程 | 78篇 |
能源动力 | 126篇 |
轻工业 | 213篇 |
水利工程 | 93篇 |
石油天然气 | 186篇 |
武器工业 | 145篇 |
无线电 | 536篇 |
一般工业技术 | 559篇 |
冶金工业 | 133篇 |
原子能技术 | 20篇 |
自动化技术 | 1509篇 |
出版年
2024年 | 38篇 |
2023年 | 103篇 |
2022年 | 168篇 |
2021年 | 201篇 |
2020年 | 193篇 |
2019年 | 185篇 |
2018年 | 182篇 |
2017年 | 212篇 |
2016年 | 236篇 |
2015年 | 232篇 |
2014年 | 284篇 |
2013年 | 378篇 |
2012年 | 366篇 |
2011年 | 322篇 |
2010年 | 254篇 |
2009年 | 251篇 |
2008年 | 272篇 |
2007年 | 273篇 |
2006年 | 270篇 |
2005年 | 207篇 |
2004年 | 182篇 |
2003年 | 135篇 |
2002年 | 110篇 |
2001年 | 100篇 |
2000年 | 80篇 |
1999年 | 56篇 |
1998年 | 56篇 |
1997年 | 35篇 |
1996年 | 51篇 |
1995年 | 37篇 |
1994年 | 25篇 |
1993年 | 21篇 |
1992年 | 23篇 |
1991年 | 24篇 |
1990年 | 8篇 |
1989年 | 14篇 |
1988年 | 8篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 7篇 |
1984年 | 9篇 |
1983年 | 4篇 |
1981年 | 3篇 |
1978年 | 1篇 |
1972年 | 1篇 |
1967年 | 2篇 |
1965年 | 1篇 |
1964年 | 2篇 |
1959年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有5640条查询结果,搜索用时 31 毫秒
1.
2.
Effects of breed and age at slaughter on degradation of muscle lipids during processing of dry‐cured hams
下载免费PDF全文
![点击此处可从《International Journal of Food Science & Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Linda Storrustløkken Hanne Marie Devle Lars Erik Gangsei Carl Fredrik Naess‐Andresen Bjørg Egelandsdal Ole Alvseike Dag Ekeberg 《International Journal of Food Science & Technology》2015,50(8):1933-1943
Hams from Landrace, Duroc and Hampshire pigs slaughtered at ages 6, 7.5 and 9 months were processed to generate Norwegian Parma‐style hams. Lipid contents and the compositions of fatty acid classes (ΣSFA, ΣMUFA, ΣPUFA) within neutral lipids, phospholipids and free fatty acids were determined. Small differences in lipid degradation and composition of the classes were revealed. However, significant sensory differences related to lipids were observed. Breed was more important than age. Dry‐cured Hampshire hams gave a more intense mature odour that may be associated with higher overall lipid degradation. Unexpectedly, these hams also demonstrated high juiciness and tenderness, which could be related to the melting characteristics of the fat. Dry‐cured Duroc hams showed a higher susceptibility towards rancidity, presumably associated with preferential oxidation of n‐6 fatty acids relative to C18:1 n‐9. Dry‐cured Landrace hams showed the lowest juiciness and tenderness, likely due to their lower fat content (marbling). 相似文献
3.
This paper investigates a novel compound control scheme combined with the advantages of trajectory linearization control (TLC) and alternative active disturbance rejection control (ADRC) for hypersonic reentry vehicle (HRV) attitude tracking system with bounded uncertainties. Firstly, in order to overcome actuator saturation problem, nonlinear tracking differentiator (TD) is applied in the attitude loop to achieve fewer control consumption. Then, linear extended state observers (LESO) are constructed to estimate the uncertainties acting on the LTV system in the attitude and angular rate loop. In addition, feedback linearization (FL) based controllers are designed using estimates of uncertainties generated by LESO in each loop, which enable the tracking error for closed-loop system in the presence of large uncertainties to converge to the residual set of the origin asymptotically. Finally, the compound controllers are derived by integrating with the nominal controller for open-loop nonlinear system and FL based controller. Also, comparisons and simulation results are presented to illustrate the effectiveness of the control strategy. 相似文献
4.
Expanded gamut printing is an approach in color reproduction that expands the color gamut of conventional CMYK printing processes via the use of additional colorants, such as Orange, Green, and Violet inks. This study evaluates the ability of commercial color management software to create an accurate solution for an expanded gamut printing system. In this study, two printing processes were used, an Epson SureColor P9000 inkjet printer/proofer and an HP Indigo 7900 digital production press, both with 7-color expanded gamut ink sets. Software solutions from Alwan, CGS ORIS, ColorLogic, GMG Color, Heidelberg, and Kodak were evaluated. The systems were tested to see how well they could reproduce the colors in the entire PANTONE+ Solid Coated spot color library. It is shown that the solutions are able to reproduce 89% to 94% of the spot colors on the Epson P9000 inkjet printer and 77% to 87% of the library on the Indigo 7900, both to less than two CIEDE2000 (a typical tolerance in label and packaging work). The number of color patches in expanded gamut characterization test charts was noted, as this is still an area of proprietary, nonstandardized working practice. There are many different colorant combinations that can make the same color in expanded gamut printing. The ink build created by the different software solutions was studied, as it relates to press stability through appropriate choice of colorants. Pantone and Adobe provide everyday commercial tools for expanded color workflows. The study identified some issues with products from these companies that could confuse a less-skilled user in a busy production environment. The conclusion of the study is that expanded gamut solutions for spot color printing produce totally acceptable results for digital printing processes; expanded gamut printing is ready, here and now. The findings show that expanded gamut printing can replace cumbersome conventional spot color workflows creating considerable savings and advantages, especially for label and packaging printers. 相似文献
5.
Francesco Di Girolamo Andrea Masotti Isabella Lante Margherita Scapaticci Cosima Damiana Calvano Carlo Zambonin Maurizio Muraca Lorenza Putignani 《International journal of molecular sciences》2015,16(9):20896-20912
Extra virgin olive oil (EVOO) with its nutraceutical characteristics substantially contributes as a major nutrient to the health benefit of the Mediterranean diet. Unfortunately, the adulteration of EVOO with less expensive oils (e.g., peanut and corn oils), has become one of the biggest source of agricultural fraud in the European Union, with important health implications for consumers, mainly due to the introduction of seed oil-derived allergens causing, especially in children, severe food allergy phenomena. In this regard, revealing adulterations of EVOO is of fundamental importance for health care and prevention reasons, especially in children. To this aim, effective analytical methods to assess EVOO purity are necessary. Here, we propose a simple, rapid, robust and very sensitive method for non-specialized mass spectrometric laboratory, based on the matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) coupled to unsupervised hierarchical clustering (UHC), principal component (PCA) and Pearson’s correlation analyses, to reveal corn oil (CO) adulterations in EVOO at very low levels (down to 0.5%). 相似文献
6.
文章介绍了3种宽带数字储频的基本结构,分析了宽带数字储频的一个重要指标——量化噪声,根据输出信号频谱的杂散电平比较了三种结构的优劣。 相似文献
7.
2.4GHz动态CMOS分频器的设计 总被引:1,自引:0,他引:1
对现阶段的主流高速CMOS分频器进行分析和比较,在此基础上设计一种采用TSPC(truesingle phase clock)和E-TSPC(extended TSPC)技术的前置双模分频器电路.该分频器大大提高了工作频率,采用0.6μm CMOS工艺参数进行仿真的结果表明,在5V电源电压下,最高频率达到3GHz,功耗仅为8mW. 相似文献
8.
9.
Sme concepts used in knowledge base maintenace,such as sequence,new law,user‘s rejection and reconstructions of a knowledge base,are first introduced,and then a framework for extended logic programming(ELP)is given,where an extended logic program is equivalent to a knowledge base.A transition system called R-calculus for ELP is provided.For a given knowledge base and a user‘s rejection,the R-calculus for ELP will deduce best revisions of the base.The soundness and the completeness of the R-calculus for ELP are proved,and the R-calculus for ELP is implemented in Prolog.In addition,the research is compared with other relevant work. 相似文献
10.