全文获取类型
收费全文 | 421篇 |
免费 | 39篇 |
国内免费 | 2篇 |
专业分类
化学工业 | 25篇 |
机械仪表 | 4篇 |
能源动力 | 2篇 |
轻工业 | 429篇 |
一般工业技术 | 1篇 |
自动化技术 | 1篇 |
出版年
2023年 | 4篇 |
2022年 | 10篇 |
2021年 | 13篇 |
2020年 | 18篇 |
2019年 | 24篇 |
2018年 | 19篇 |
2017年 | 22篇 |
2016年 | 19篇 |
2015年 | 23篇 |
2014年 | 19篇 |
2013年 | 23篇 |
2012年 | 26篇 |
2011年 | 42篇 |
2010年 | 22篇 |
2009年 | 12篇 |
2008年 | 15篇 |
2007年 | 32篇 |
2006年 | 20篇 |
2005年 | 15篇 |
2004年 | 12篇 |
2003年 | 14篇 |
2002年 | 12篇 |
2001年 | 11篇 |
2000年 | 8篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
排序方式: 共有462条查询结果,搜索用时 15 毫秒
1.
P. CRISP T.J. WICKS D. BRUER E.S. SCOTT 《Australian Journal of Grape and Wine Research》2006,12(3):203-211
Grapevine powdery mildew ( Erysiphe necator) affects grape yield and fruit quality worldwide. Managers of conventional vineyards rely mainly on synthetic fungicides and sulfur to control powdery mildew, while in organic vineyards sulfur is the main control agent, often in rotation with canola-based oils, bicarbonates and biological control agents. The efficacy of those materials has not been evaluated critically under field conditions in Australia. Accordingly, a range of materials showing most promise in previous greenhouse trials (Crisp et al. 2006 Australian Journal of Grape and Wine Research 12 , pp. 192–202) were assessed via field trials in commercial vineyards. Applications of either milk or whey (alone, or mixed with a canola oil-based product), as well as applications of potassium bicarbonate (commercial formulation), all reduced the severity of powdery mildew compared with untreated vines. Eight applications of a 1:10 dilution of milk, 45 g/L whey powder or programs comprising rotations of potassium bicarbonate plus oil and whey, applied at 10–14 day intervals, reduced the severity of powdery mildew to levels not significantly different from that on vines sprayed with sulfur (wettable powder, 3–6 g/L). However, the relative control of powdery mildew by the test materials in field trials was dependent on the susceptibility of the grapevine cultivar and the extent of spray coverage achieved. In vineyards where highly susceptible cultivars were planted, and spray coverage was compromised, the resultant control of powdery mildew was reduced; and sometimes to commercially unacceptable levels. 相似文献
2.
Bruno Gabel Denis Thiéry Vaclav Suchy Frédéric Marion-Poll Peter Hradsky Pavel Farkas 《Journal of chemical ecology》1992,18(5):693-701
The European grapevine moth (EGVM),Lobesia botrana, is a major pest of grapes in Europe. Females are attracted to a nonhost plant: tansy (Tanacetum vulgare L.), which is a common weed in Slovakian vineyards. A steam distillate extract of tansy flowers was analyzed by means of a GC-EAG technique to screen constituents detected by the olfactory receptors of EGVM females. From more than 200 GC peaks, nine peaks corresponding to monoterpenoids released an EAG response in more than 70% of the females (N=15):p-cymene,d-limonene,-thujene,-thujone,-thujone, thujyl alcohol, terpinene-4-ol, (Z)-verbenol, and piperitone. The steam distillate of tansy as well as a synthetic blend of identified compounds released consistent attraction in a field cage. The use of nonhost plants and host plant odors in integrated pest management is discussed. 相似文献
3.
Fortuna Iannuzzo Vincenzo Piccolo Ettore Novellino Elisabetta Schiano Emanuela Salviati Vincenzo Summa Pietro Campiglia Gian Carlo Tenore Maria Maisto 《International journal of molecular sciences》2022,23(21)
Proanthocyanidins (PACs) are a group of bioactive molecules found in a variety of plants and foods. Their bioavailability depends on their molecular size, with monomers and dimers being more bioavailable than those that have a higher polymerization degree. This study aimed to develop a method to convert high-molecular-weight PACs to low-molecular-weight ones in a grape seed extract (GSE) from Vitis vinifera L. Therefore, GSE was subjected to alkaline treatment (ATGSE), and its difference in chemical composition, compared to GSE, was evaluated using a molecular networking (MN) approach based on results obtained from HPLC-ESI HRMS/MS characterization analysis. The network analysis mainly noted the PAC cluster with about 142 PAC compounds identified. In particular, the obtained results showed a higher content of monomeric and dimeric PACs in ATGSE compared to GSE, with 58% and 49% monomers and 31% and 24% dimers, respectively. Conversely, trimeric (9%), polymeric (4%), and galloylated PACs (14%) were more abundant in GSE than in ATGSE (6%, 1%, and 4%, respectively). Moreover, in vitro antioxidant and anti-inflammatory activities were investigated, showing the high beneficial potential of both extracts. In conclusion, ATGSE could represent an innovative natural matrix rich in bioavailable and bioaccessible PACs for nutraceutical applications with potential beneficial properties. 相似文献
4.
乙醇沉淀法提取葡萄多糖的研究 总被引:1,自引:0,他引:1
利用乙醇沉淀法提取葡萄多糖。研究表明此法提取葡萄多糖的最佳条件为:温度90℃,时间2h,料液体积比1∶2,次数为3。在提取液浓缩至原体积1/10的基础上用6倍体积的体积浓度95%乙醇进行沉淀。根据最佳提取工艺可使葡萄多糖的提取率达到99.9%。 相似文献
5.
本试验以刺葡萄已萌发的种子为试材,用不同浓度的秋水仙素(0、0.2%、0.3%、0.4%)处理不同时间(0、24h、36h、48h、60h),观察其诱变效果。结果表明,0.3%秋水仙素处理48h的诱变率在所有处理中为最高(36.8%),0.4%秋水仙素处理48h次之(33.3%),但二者存在极显著差异;0.4%秋水仙素的不同时间处理中,致死率随处理时间延长而增高,诱变植株数递减。 相似文献
6.
7.
Analysis of tannins in seeds and skins of Shiraz grapes throughout berry development 总被引:2,自引:0,他引:2
MARK O. DOWNEY JOHN S. HARVEY SIMON P. ROBINSON 《Australian Journal of Grape and Wine Research》2003,9(1):15-27
The flavan-3-ol and proanthocyanidin composition of both seeds and skin of Vitis vinifera L. cv. Shiraz grapes was determined by reversed-phase HPLC after acetone extraction and acid-catalysis in the presence of excess phloroglucinol. Samples were taken at weekly intervals from fruit-set until commercial harvest. The main period of proanthocyanidin accumulation in grape seeds occurred immediately after fruit-set with maximum levels observed around veraison. Over two seasons there was variation in both the timing and content of proanthocyanidins in seeds. In skin, proanthocyanidin accumulation occurred from fruit set until 1–2 weeks after veraison. Proanthocyanidin subunit composition was different in seeds and skin and changed during berry development but the mean degree of polymerisation of the tannin polymers in skins was higher than in the seeds at all stages of berry development. Proanthocyanidin levels in both seeds and skin decreased between veraison and harvest. Additional proanthocyanidin subunits were released when the residues remaining after acetone extraction were subjected to direct acid-catalysis in the presence of phloroglucinol. In the seeds, these accounted for much of the post-veraison decrease, but not in grape skin. At harvest, 75% of extractable berry proanthocyanidin was in the seeds. Accumulation of proanthocyanidins in the seeds appears to be independent of that in the skins, but in both tissues synthesis occurs early in berry development and maximum levels are reached around veraison. 相似文献
8.
9.
湖南刺葡萄酒主要呈香物质的分析 总被引:1,自引:0,他引:1
采用顶空固相微萃取(HS-SPME)结合气相色谱-质谱联用技术(GC-MS),对湖南省3个品种刺葡萄(米葡萄、涩葡萄和甜葡萄)酒的挥发性组分进行了检测,并根据定量结果和各物质的感官阈值对每种物质的香气活性值(OAV)进行计算。结果表明,3个品种刺葡萄酒中共检出挥发性组分90种,主要包括高级醇类、酯类、萜烯类及C6类化合物等。OAV>1的挥发性组分有21种,包括β-大马士酮、异戊酸乙酯、丁酸乙酯等。基于雷达图的分析结果表明,3个品种刺葡萄酒的香气轮廓较为相似,主要呈现果香、花香和甜香。 相似文献
10.
以市场上常见的8种活性干酵母作为山葡萄北国蓝的发酵剂,通过比较发酵速率、定性定量分析蒸馏酒中香气成分,并结合主成分分析(PCA),综合得出适合酿造山葡萄北国蓝蒸馏酒的酿酒酵母。结果表明,在发酵过程中,发酵速率最快的是酵母ADT,酵母CEC01次之;发酵完成后,酵母菌MST的发酵原酒酒精度最高,为(9.80±0.11)%vol,发酵最彻底,产酒能力优于其他酵母(P<0.05),其次是酵母CEC01,为(9.79±0.01)%vol;酵母菌CEC01发酵的山葡萄蒸馏酒中挥发性物质含量最高,为16 394.24 μg/L,其次是酵母VF(16 163.22 μg/L)、ADT(15 576.32 μg/L);主成分分析综合得分最高的是酵母CEC01,其次是酵母ADT。由此可得,酵母CEC01、ADT发酵能力强,产酒率高,且蒸馏酒的酒香浓郁、品质较好,适合酿造山葡萄蒸馏酒。 相似文献