全文获取类型
收费全文 | 744篇 |
免费 | 22篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 4篇 |
综合类 | 27篇 |
化学工业 | 125篇 |
金属工艺 | 2篇 |
机械仪表 | 20篇 |
建筑科学 | 58篇 |
矿业工程 | 6篇 |
能源动力 | 6篇 |
轻工业 | 372篇 |
水利工程 | 4篇 |
石油天然气 | 55篇 |
武器工业 | 1篇 |
无线电 | 14篇 |
一般工业技术 | 21篇 |
冶金工业 | 4篇 |
原子能技术 | 3篇 |
自动化技术 | 49篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 10篇 |
2020年 | 18篇 |
2019年 | 7篇 |
2018年 | 17篇 |
2017年 | 35篇 |
2016年 | 24篇 |
2015年 | 20篇 |
2014年 | 45篇 |
2013年 | 55篇 |
2012年 | 46篇 |
2011年 | 67篇 |
2010年 | 48篇 |
2009年 | 57篇 |
2008年 | 59篇 |
2007年 | 60篇 |
2006年 | 37篇 |
2005年 | 21篇 |
2004年 | 24篇 |
2003年 | 32篇 |
2002年 | 23篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1989年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有771条查询结果,搜索用时 156 毫秒
71.
具体分析了日本振兴工业设计的三要素及日本在此方面所作的努力,希望能为振兴我国的工业设计提供有益的借鉴。 相似文献
72.
通过对电视频道整体包装和品牌建设的关系再认识,具体分析了电视频道包装系统的核心内涵,从理念识别系统、视觉识别系统、行为识别系统入手,详细阐述了建立频道形象包装识别系统,打造优势品牌的具体内容,并指出电视品牌时代频道包装的个性化、人文化、内在化、规范化和时尚化的发展趋势. 相似文献
73.
Qingbiao Wang Yong Yang Xiaomin Zhao Bin Zhu Peng Nan Jiayuan Zhao Li Wang Fan Chen Zhijun Liu Yang Zhong 《Food chemistry》2006,98(1):52-58
Hydro-distillated volatile oils of Ephedra sinica Stapf. from six populations of Inner Mongolia in Northeastern China were analyzed by using GC/MS. Ninety-nine compounds were identified in the oils and a relatively high variation in their contents was found. The main constituents of the essential oils were α-terpineol (19.28–52.23%), p-vinylanisole (0.59–11.64%), 3-methyl-2-buten-1-ol (0–5.44%), tetramethylpyrazine (0.63–8.99%), terpine-4-ol (1.17–4.37%), α-linalool (1.62–5.15%), phytol (1.24–15.73%), γ-eudesmol (0–7.77%), and eudesm-7(11)-en-4-ol (0.41–6.13). Six populations were divided into two chemotypes based on cluster analysis and principal component analysis (PCA); one rich in α-terpineol and p-vinylanisole, and the other rich in phytol, γ-eudesmol, and eudesm-7(11)-en-4-ol. 相似文献
74.
本文在界定乡土建筑内涵的基础上,指出可以从乡土建筑的群体布局,平面布置,建筑细部中吸取有益成分,进行现代建筑设计. 相似文献
75.
Adam Figiel Antoni Szumny Antonio Gutiérrez-Ortíz Ángel A. Carbonell-Barrachina 《Journal of food engineering》2010
The influence of the drying method on volatile compounds of Origanum vulgare was evaluated. The drying methods tested were convective (CD) at 60 °C and vacuum-microwave (VMD), as well as a combination of convective pre-drying and VM finish-drying (CPD–VMFD). The volatile compounds of fresh and dried oregano were extracted by steam-hydrodistillation and analyzed by GC–MS. Oregano drying kinetics was described by a simple exponential model for CD and CPD–VMFD, while VMD kinetics consisted of two periods: linear until a critical point and exponential beyond that point. Thirty-four compounds were tentatively identified, with carvacrol, thymol, and γ-terpinene, being the major components. The total volatiles concentration of fresh oregano (33.0 g kg−1) decreased significantly during drying, independently of the method used (CD: 10.2 g kg−1, CPD–VMFD: 13.1 g kg−1, and VMD: 27.9 g kg−1). The final conclusion was that VM dehydrated Polish oregano was of better aromatic quality than that dried using hot air. 相似文献
76.
Fatty acids and essential oils from hydroponically cultivated Salvia officinalis leaves were analyzed by GC and GC–MS. Four different levels of NaCl (25, 50, 75 and 100 mM) were applied. The first results showed that salt treatment reduced significantly the plant growth by 61% and the total fatty acids (TFA) content by 32% at 100 mM NaCl. Alpha-linolenic, gadoleic, palmitic and oleic acids were the major fatty acids. Moreover, the polyunsaturated fatty acids decreased, while the monounsaturated ones increased with respect to increasing salinity. Regarding the essential oil composition, the main compounds were α-and β-thujone, 1,8-cineole, camphor, α-humulene, viridiflorol and manool at all salt treatments. The yield had a maximum increase at 75 mM NaCl. Hence, sage can be considered as moderately salt sensitive. 相似文献
77.
J. Gómez-Estaca A. López de LaceyM.E. López-Caballero M.C. Gómez-GuillénP. Montero 《Food microbiology》2010
Essential oils of clove (Syzygium aromaticum L.), fennel (Foeniculum vulgare Miller), cypress (Cupressus sempervirens L.), lavender (Lavandula angustifolia), thyme (Thymus vulgaris L.), herb-of-the-cross (Verbena officinalis L.), pine (Pinus sylvestris) and rosemary (Rosmarinus officinalis) were tested for their antimicrobial activity on 18 genera of bacteria, which included some important food pathogen and spoilage bacteria. Clove essential oil showed the highest inhibitory effect, followed by rosemary and lavender. In an attempt to evaluate the usefulness of these essential oils as food preservatives, they were also tested on an extract made of fish, where clove and thyme essential oils were the most effective. Then, gelatin–chitosan-based edible films incorporated with clove essential oil were elaborated and their antimicrobial activity tested against six selected microorganisms: Pseudomonas fluorescens, Shewanella putrefaciens, Photobacterium phosphoreum, Listeria innocua, Escherichia coli and Lactobacillus acidophilus. The clove-containing films inhibited all these microorganisms irrespectively of the film matrix or type of microorganism. In a further experiment, when the complex gelatin–chitosan film incorporating clove essential oil was applied to fish during chilled storage, the growth of microorganisms was drastically reduced in gram-negative bacteria, especially enterobacteria, while lactic acid bacteria remained practically constant for much of the storage period. The effect on the microorganisms during this period was in accordance with biochemical indexes of quality, indicating the viability of these films for fish preservation. 相似文献
78.
In this study, total contents of phenolic, flavanol and flavonol, antioxidant activities and antimicrobial activities of the Turkish endemic Salvia pisidica Boiss. & Heldr. ex Bentham (Lamiaceae) extract and essential oil were assessed in vitro. Total phenolic, flavanol and flavonol contents in the extract were 54.57 mg gallic acid equivalents (GAE)/g, 16.70 mg catechine equivalents (CE)/g and 18.19 mg rutin equivalents (RE)/g, respectively. Antioxidant activities (IC50 value) of the extract and essential oil were determined as 4.88 and 6.41 mg/mL by DPPH assay, respectively. 31 compounds were determined in the essential oil using GC-MS and the major compounds (%) were camphor (23.76), sabinol (19.2), α-thujone (14.2) and eucalyptol (1.8-cineole) (5.8).The antimicrobial activity of the methanolic extract and the essential oil against 13 bacterial and two yeast strains was determined. The extract (concentration 5 g/100 ml or 10 g/100 ml) was effective against most of the strains tested, yet not against Bacillus cereus, Staphylococcus aureus, Aeromonas hydrophila and the two yeast strains tested. The essential oil (2 g/100 ml) showed an antimicrobial effect against all the gram (+) bacteria tested, against Saccharomyces cerevisiae, but was not effective against all gram (−) bacteria and Candida albicans. These results show that S.piscidica essential oil and extract could be considered as a natural alternative to traditional food preservatives and be used to enhance food safety and shelf life. 相似文献
79.
Six perennial groundcovers including Alchemilla mollis, Nepeta × faassenii, Phlox subulata, Sedum acre, Solidago cutleri, and Thymus praecox were investigated for the allelopathic potential of their respective foliar tissues via evaluation of volatile constituents produced by foliage. These groundcovers were selected for further laboratory evaluation because of superior performance as weed-suppressive groundcovers in previous field experiments. Foliar volatile components of N. × faassenii exhibited the strongest inhibitory effects on seedling growth of curly cress (Lepidium sativum), but S. cutleri also showed allelopathic potential by reducing shoot growth of curly cress seedlings with extracted volatiles. Although A. mollis and P. subulata exhibited strong weed-suppressive traits in past field experiments, weed suppression is apparently associated with either competition for resources or other allelopathic mechanisms rather than an allelopathic effect caused by volatiles. Volatiles of N. × faassenii were further evaluated with gas chromatography coupled to mass spectrometry (GC-MS). A total of 21 chemical constituents were identified in the volatile cocktail; 17 components were identified from a direct crude leaf sample extraction, including sabinene, β-pinene, β-myrcene, 2-(2-ethoxyethoxy)-ethanol, 1,8-cineole, ocimene, neryl Acetate, 4aα,7α,7aα-nepetalactone, α-copaene, trans-caryophyllene, alloaromadendrene, 4aβ,7α,7aβ-nepetalactone, germacrene D, β-farnesene, χ-cadinene, germacrene B, and β-sesquiphellandrene. Five additional constituents were identified in a methanolic extract of dried of N. × faassenii foliage, but not the volatile cocktail collected from N. × faassenii foliage. These included methyl benzoate, 2,4-decadienal, neryl acetate, isodihydronepetalactone, and caryophyllene oxide. Three components, 2-(2-ethoxyethoxy)-ethanol, alloaromadendrene, and χ-cadinene, were not only detected in both the volatile mixture and the methanolic extract, but also in an aqueous foliar extract that exhibited potential allelopathic activity. 相似文献
80.