全文获取类型
收费全文 | 938篇 |
免费 | 92篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 1篇 |
综合类 | 22篇 |
化学工业 | 77篇 |
机械仪表 | 13篇 |
建筑科学 | 5篇 |
矿业工程 | 1篇 |
能源动力 | 1篇 |
轻工业 | 824篇 |
石油天然气 | 11篇 |
无线电 | 8篇 |
一般工业技术 | 54篇 |
冶金工业 | 8篇 |
原子能技术 | 3篇 |
自动化技术 | 9篇 |
出版年
2024年 | 6篇 |
2023年 | 20篇 |
2022年 | 28篇 |
2021年 | 51篇 |
2020年 | 40篇 |
2019年 | 43篇 |
2018年 | 49篇 |
2017年 | 49篇 |
2016年 | 46篇 |
2015年 | 54篇 |
2014年 | 42篇 |
2013年 | 80篇 |
2012年 | 72篇 |
2011年 | 86篇 |
2010年 | 50篇 |
2009年 | 42篇 |
2008年 | 30篇 |
2007年 | 41篇 |
2006年 | 32篇 |
2005年 | 34篇 |
2004年 | 24篇 |
2003年 | 19篇 |
2002年 | 23篇 |
2001年 | 10篇 |
2000年 | 15篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 9篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有1037条查询结果,搜索用时 15 毫秒
81.
《Food Control》2015
In an effort to enforce the knowledge on mycotoxin occurrence and co-occurrence in dates and dried fruits, 228 samples purchased from Tunisian and Spanish markets were subjected to multi-mycotoxin liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis of 16 mycotoxins. At least one mycotoxin was detected in 160 samples (70%). The frequency of contaminated samples was 83%, 80%, 64%, 59% and 26% for dates, dried vine fruits, figs, apricots and plums, respectively but none of the analyzed samples contained detectable levels of fumonisins (FB1, FB2, FB3) or T-2 toxin (T2).The incidence and levels of mycotoxins varied in samples. The most prevalent mycotoxin was enniatin B (EnnB) (54%), followed by enniatinA1 (EnnA1) (36%); aflatoxins (AFs) (23%) and ochratoxin A (OTA) (22%). Thirteen samples contained AFs in levels that exceed the maximum limits established in EU legislation. The simultaneous contamination with 2–6 mycotoxins was observed in 51% of the analyzed samples. Lastly, intakes of the detected mycotoxins were calculated for average adult consumers and compared with the tolerable daily intakes (TDI). Data obtained were used to estimate the potential exposure levels. 相似文献
82.
Tania Chacón-Ordóñez Reinhold Carle Ralf Schweiggert 《Journal of the science of food and agriculture》2019,99(7):3220-3239
The frequent consumption of carotenoid-rich foods has been associated with numerous health benefits, such as the supply of provitamin A. To exert these health benefits, carotenoids need to be efficiently liberated from the food matrix, micellized in the small intestine, taken up by the enterocytes and absorbed into the human blood stream. Enormous efforts have been made to better understand these processes. Because human studies are costly, labor-intense and time-consuming, the evaluation of carotenoid liberation and micellization at the laboratory scale using simulated in vitro digestion models has proven to be an important tool for obtaining preliminary results prior to conducting human studies. In particular, the liberation from the food matrix and the intestinal micellization can be mimicked by simulated digestion, yielding an estimate of the so-called bioaccessibility of a carotenoid. In the present review, we provide an overview of the carotenoid digestion process in vivo, the currently used in vitro digestion models and the outcomes of previous bioaccessibility studies, with a special focus on correlations with concomitantly conducted human studies. Furthermore, we advocate for the on-going requirement of better standardized digestion protocols and, in addition, we provide suggestions for the complementation of the acquired knowledge and current nutritional recommendations. © 2018 Society of Chemical Industry 相似文献
83.
International agricultural trade in fruits and vegetables has received much attention as an effective method to create a sustainable agriculture industry for a country. This study focuses on consumers’ perceptions of food values toward imported fruits and vegetables in Japan, Taiwan, and Indonesia by using the Best-Worst Scaling method. Seven food values were examined in this study: labeling product origin, food safety certification, high quality appearance, domestic rarity, price, how the product was grown, and freshness. An online survey was conducted and 1,350 total valid respondents were collected (500 Japanese, 333 Taiwanese, and 517 Indonesian). The Latent Class Multinomial Logit model was used to analyze consumers for each country. Results revealed that food safety certification and freshness were found as the most important and second most important food values for the majority group of consumers in each of these three countries, respectively. However, the remainder of food values do not have the same importance for each country. The study should help governments and international marketers enhance their agricultural trade policies and marketing strategies for these targeted markets. 相似文献
84.
85.
燕麦片是一种营养丰富、方便快捷、易于携带的食品。燕麦食品能基本满足人体所需能量,但维生素和矿物质等成分相对不足,不能满足机体一餐的全部营养需求。果蔬是人体获取维生素、矿物质和膳食纤维的主要来源,与人体健康密切相关,早餐合理摄取一定量的果蔬是身体健康的重要保证。果蔬燕麦食品的开发,能更好地满足人体对营养的需要,为人们提供了更好的早餐选择。本文综述了燕麦的营养保健功能、果蔬燕麦片的开发优势,并对其未来发展趋势进行了阐述,以供果蔬燕麦食品的研究和开发提供参考。 相似文献
86.
87.
目的 对千禧果进行涂膜包装,从而延长其常温贮藏的货架期。方法 采用壳聚糖(Chitosan, CS)和羧甲基壳聚糖(CarboxymethylChitosan, CMCS)为基材,利用层层自组装(Layer-by-layer Self-assembly,LBL)的方法对千禧果进行涂膜保鲜包装,研究CS与CMCS之间的作用力类型,以及涂膜处理对千禧果的保鲜效果。结果 通过红外分析可知,CS与CMCS之间依靠氢键作用和静电力相互连接;通过实验确定CMCS/CS层层自组装双层涂膜对千禧果的保鲜效果相对最佳,在室温下能将千禧果的保鲜期延长至9d,贮藏9d后千禧果的质量损失率、腐烂率、硬度、可溶性固形物质量分数、维生素C含量及有机酸含量分别为3.3%、6.7%、5.3 kg/cm2、7.7%、29.3 mg/hg和0.48%。结论 CS和CMCS层层自组装多层涂膜对千禧果具有明显的保鲜效果,能有效延长其货架期。 相似文献
88.
对果蔬预冷应用场合,本文提出一种冰浆式湿冷蒸发器,并将其应用于小型模拟冷库。采用娃娃菜为被冷却对象,以库内温度和相对湿度为指标,改变填料类型(金属、塑料、纸质填料)和载冷介质(冰浆、冷水),在冷库空载条件下进行负载预冷实验。结果表明:金属、纸质填料的换热能力较塑料填料好;与冷水相比,以冰浆为载冷介质,预冷时间缩短了1/6并保持更低的库内温度,库内相对湿度稳定后均能保持在90%以上;预冷后样品失重率较冷水的小0.19%;冰浆式湿冷蒸发器可在冷库中稳定运行,且较冷水为载冷介质的湿冷蒸发器,可更高效地实现预冷过程的低温(3~6 ℃)高湿(>90%RH)环境,适用于果蔬预冷和保鲜。 相似文献
89.
Occlusion is one of the key factors affecting the success rate of vision-based fruit-picking robots. It is important to accurately locate and grasp the occluded fruit in field applications, However, there is yet no universal and effective solution. In this paper, a high-precision estimation method of spatial geometric features of occluded targets based on deep learning and multisource images is presented, enabling the selective harvest robot to envision the whole target fruit as if its occlusions do not exist. First, RGB, depth and infrared images are acquired. And pixel-level matched RGB-D-I fusion images are obtained by image registration. Second, aiming at the problem of detecting the occluded tomatoes in the greenhouse, an extended Mask-RCNN network is designed to extract the target tomato. The target segmentation accuracy is improved by 7.6%. Then, for partially occluded tomatoes, a shape and position restoration method is used to recover the obscured tomato. This algorithm can extract tomato radius and centroid coordinates directly from the restored depth image. The mean Intersection over Union is 0.895, and the centroid position error is 0.62 mm for the occluded rate under 25% and the illuminance between 1 and 12 KLux. And hereby a dual-arm robotic harvesting system is improved to achieve a picking time of 11 s per fruit, an average gripping accuracy of 8.21 mm, and an average picking success rate of 73.04%. The proposed approach realizes a high-fidelity geometrics reconstruction instead of mere image style restoration, which endows the robot with the ability to see through obstacles in the field scenes and improves its operational success rate in its result. 相似文献
90.
Candan Turkkan 《Journal of Urbanism》2020,13(1):13-37
ABSTRACTThis article focuses on the effects of urban transformation on the urban food supply chain in 21st century Istanbul. The article begins with a discussion on the particularities of the urban transformation that has shaped the city since the 1980s, emphasizing tendencies that are relevant to food consumption and supply patterns and practices. Next, 6 categories of fresh fruits and vegetables (FFVs), provisioning agents (mixed/foreign-capital supermarkets, domestic-capital supermarkets, bazaars, local suppliers, and urban and semi-urban/peripheral farmers, internet or store-based alternative food networks) are analyzed in terms of their perception of urban transformation and various challenges it poses. The article concludes with an assessment of the changes in the city’s food supply chain in light of provisioning agents’ responses to the urban transformation as a force that either enables them compete more successfully and expand their operations or pushes them to contract or even leave the provisioning sector completely. 相似文献