全文获取类型
收费全文 | 1044篇 |
免费 | 75篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 1篇 |
综合类 | 18篇 |
化学工业 | 215篇 |
金属工艺 | 9篇 |
机械仪表 | 5篇 |
建筑科学 | 2篇 |
矿业工程 | 5篇 |
能源动力 | 2篇 |
轻工业 | 831篇 |
水利工程 | 3篇 |
石油天然气 | 19篇 |
无线电 | 2篇 |
一般工业技术 | 8篇 |
冶金工业 | 1篇 |
原子能技术 | 6篇 |
自动化技术 | 2篇 |
出版年
2024年 | 12篇 |
2023年 | 14篇 |
2022年 | 34篇 |
2021年 | 49篇 |
2020年 | 51篇 |
2019年 | 54篇 |
2018年 | 39篇 |
2017年 | 43篇 |
2016年 | 52篇 |
2015年 | 38篇 |
2014年 | 54篇 |
2013年 | 87篇 |
2012年 | 67篇 |
2011年 | 91篇 |
2010年 | 43篇 |
2009年 | 38篇 |
2008年 | 45篇 |
2007年 | 72篇 |
2006年 | 59篇 |
2005年 | 20篇 |
2004年 | 17篇 |
2003年 | 31篇 |
2002年 | 20篇 |
2001年 | 16篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 9篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有1129条查询结果,搜索用时 53 毫秒
61.
Volatiles of the diethyl ether extracts of I. gabonensis, C. lanatus and A. hypogaea attracted 1–7 and 28–42-day-old adult O. mercator when tested in a two-choice pitfall Petri dish bioassay. For both age groups, a significant difference was observed in response between fed and starved adults to the different extracts. Differences in starvation time did not affect responses of individuals in the 1–7-day-old group; a significant effect was observed in the 28–42-day-old group.
Adults, 28–42-day-old were significantly more responsive to virtually all extracts than 1–7-day-old adults. Responses of adults in each age group to the different extracts were not significantly different. The time of trial within the period 0900–1900 h did not significantly affect the response of adults in both age groups, starved for 2 days, to any extract. 相似文献
62.
三叉苦提取物抗氧化作用的研究 总被引:6,自引:0,他引:6
目的:研究三叉苦不同部位水提取物的抗氧化作用及其规律,为食品或药物抗氧化剂的筛选和应用提供理论依据。方法:应用化学发光法检测三叉苦的各部位水提取物对邻苯三酚 -CTMAB 体系产生的超氧阴离子自由基(O2·)、邻菲罗啉 - 抗坏血酸体系产生的羟自由基(·OH)及过氧化氢(H2O2)的清除作用。结果:三叉苦水提取物具有明显的清除超氧阴离子自由基、羟自由基和过氧化氢的作用,清除率与浓度之间存在着明显的量效关系。结论:证明了三叉苦各部位的水提取物均是一种有效的抗氧化剂。 相似文献
63.
香辛料提取物在肉品保鲜中的作用及应用 总被引:1,自引:1,他引:1
天然香辛料提取物对肉品具有抑菌防腐作用和抗氧化作用,可用于肉品保鲜。本文主要论述了香辛料提取物的提取和使用方法、对肉品的作用以及其作为保鲜剂在冷却肉和肉制品中的应用情况。 相似文献
64.
Total Phenolic Compounds, Flavonoids, and Radical Scavenging Activity of 21 Selected Tropical Plants
ABSTRACT: Free radical scavenging activity of 21 tropical plant extracts was evaluated using 1,1-diphenyl-2-picrylhydrazyl assay (DPPH). Total phenolic compounds and flavonoids were determined using Folin–Ciocalteu and HPLC, respectively. Results of the study revealed that all the plants tested exhibited excellent antioxidant activity with IC50 in the range of 21.3 to 89.6 μg/mL. The most potent activity was demonstrated by Cosmos caudatus (21.3 μg/mL) and Piper betle (23.0 μg/mL) that are not significantly different than that of -tocopherol or BHA. L. inermis extract was found to consist of the highest concentration of phenolics, catechin, epicatechin, and naringenin. High content of quercetin, myricetin, and kaempferol were identified in Vitex negundo , Centella asiatica , and Sesbania grandiflora extracts, respectively. Luteolin and apigenin, on the other hand, were found in Premna cordifolia and Kaempferia galanga extracts. Strong correlation ( R = 0.8613) between total phenolic compounds and total flavonoids ( R = 0.8430) and that of antioxidant activity of the extracts were observed. The study revealed that phenolic, in particular flavonoids, may be the main contributors to the antioxidant activity exhibited by the plants.
Practical Application: Potent antioxidant from natural sources is of great interest to replace the use of synthetic antioxidants. In addition, some of the plants have great potential to be used in the development of functional ingredients/foods that are currently in demand for the health benefits associated with their use. 相似文献
Practical Application: Potent antioxidant from natural sources is of great interest to replace the use of synthetic antioxidants. In addition, some of the plants have great potential to be used in the development of functional ingredients/foods that are currently in demand for the health benefits associated with their use. 相似文献
65.
Two known repellents of stored-product insects, DEET and neem, were compared to protein-enriched pea flour, defatted protein-enriched pea flour, and pea protein extract for their efficacy at reducing penetration and invasion by several common stored-product insects: Sitophilus oryzae (L.), Tribolium castaneum (Herbst), Cryptolestes ferrugineus (Stephens), and Oryzaephilus surinamensis (L.). The methods of preparation of pea extract affected the penetration of S. oryzae. Protein-enriched pea flour, DEET and neem reduced the penetration of S. oryzae, but defatted protein-enriched pea flour and pea protein extract did not. The number of S. oryzae, T. castaneum, C. ferrugineus and O. surinamensis entering pierced paper envelopes that contained wheat and were treated with DEET was reduced by 99%, 86%, 97% and 91%, respectively. Neem was less effective than DEET in reducing penetration and invasion of insects. Protein-enriched pea flour did not prevent insects entering pierced envelopes. 相似文献
66.
以新余蜜橘为试材,研究在贮藏温度(5±1)℃,相对湿度(RH)85%~90%条件下,桂枝提取液对新余蜜橘贮藏保鲜效果的影响。结果表明:与对照相比,贮藏中后期(30~90d),桂枝提取液能显著减少新余蜜橘烂果数,降低果实失重率和丙二醛(MDA)含量,延缓可溶性固形物(TSS)、可滴定酸(TA)、VC及总糖含量的降解速率,维持贮藏后期较高的超氧化物岐化酶(SOD)、苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)以及多酚氧化酶(PPO)活性,从而能有效保持果实采后的贮藏特性,延长保鲜期。 相似文献
67.
6 种东北地区红树莓果渣提取物的抗氧化活性差异 总被引:3,自引:0,他引:3
以东北地区6 种红树莓果实加工后的果渣提取物为实验材料,研究其总酚、总黄酮、原花青素、花色苷含量和体外抗氧化活性的差异。结果表明:宝石红果渣提取物中总酚、总黄酮和原花青素含量最高,分别为14.18、3.71、15.28 mg/g;哈瑞太兹果渣提取物中花色苷含量最高,为0.68 mg/g;菲尔杜德和野生果果渣提取物的总还原能力与VC接近;除哈瑞太兹外,其他品种红树莓果渣提取物对(1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基和2,2’-二氮-双(3-乙基苯并噻唑-6-磺酸)二铵盐自由基(2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical,ABTS+·)的清除率均大于VC。相关性分析结果表明红树莓果渣提取物的总还原能力与总黄酮、原花青素含量的相关性较大;对DPPH自由基的清除率与原花青素、花色苷含量的相关性较大;而对ABTS+·的清除率与总酚和总黄酮含量的相关性较大。在6 个红树莓品种中,菲尔杜德和野生果果渣提取物具有较强的抗氧化活性。 相似文献
68.
The Mediterranean diet is considered one of the healthiest diets in the world. This is often attributed to low saturated fat consumption, moderate wine consumption, and high vegetable consumption. However, herbs and spices associated with these diets may also play an important role in the quality of this diet. This review summarizes the most recent research regarding the anti-diabetic, anti-inflammatory, anti-hyperlipidemic and anti-hypertensive properties of this collection of culinary species. Additionally, this review briefly summarizes studies performed on lesser known herbs from around the world, with the goal of identifying new culinary species that may be useful in the treatment or prevention of diseases. 相似文献
69.
Anti‐adhesion activity of thyme (Thymus vulgaris L.) extract,thyme post‐distillation waste,and olive (Olea europea L.) leaf extract against Campylobacter jejuni on polystyrene and intestine epithelial cells 下载免费PDF全文
70.