全文获取类型
收费全文 | 449篇 |
免费 | 29篇 |
专业分类
林业 | 31篇 |
农学 | 22篇 |
130篇 | |
综合类 | 19篇 |
农作物 | 24篇 |
水产渔业 | 11篇 |
畜牧兽医 | 194篇 |
园艺 | 11篇 |
植物保护 | 36篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 18篇 |
2020年 | 22篇 |
2019年 | 15篇 |
2018年 | 14篇 |
2017年 | 22篇 |
2016年 | 23篇 |
2015年 | 24篇 |
2014年 | 21篇 |
2013年 | 41篇 |
2012年 | 43篇 |
2011年 | 28篇 |
2010年 | 25篇 |
2009年 | 15篇 |
2008年 | 31篇 |
2007年 | 24篇 |
2006年 | 21篇 |
2005年 | 17篇 |
2004年 | 12篇 |
2003年 | 10篇 |
2002年 | 13篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有478条查询结果,搜索用时 15 毫秒
51.
52.
Bodi D Fry H Schafft H Lahrssen-Wiederholt M Preiss-Weigert A 《Journal of agricultural and food chemistry》2012,60(28):6946-6952
Maduramicin is a coccidiostat authorized as feed additive in the European Union for chickens and turkeys for fattening but not for laying hens, considering the risk of residues in eggs. The unavoidable cross-contamination of non-target feed with coccidiostats is regulated by Commission Directive 2009/8/EC and resulting carry-over in food by Commission Regulation (EC) No. 124/2009. To verify the compliance of the maximum levels for maduramicin in feed (50 μg/kg) and eggs (2 μg/kg), the carry-over from feed into eggs was investigated. Diets containing 10, 30, and 50 μg of maduramicin/kg of feed were fed to laying hens. Feed, egg white, and yolk were analyzed by LC-MS/MS. Maduramicin residues were only detected in in egg yolk. Feeding the 10 μg/kg maduramicin diet resulted in maduramicin concentrations up to 2.5 μg/kg in whole eggs, already exceeding the maximum level. A carry-over rate of 8% maduramicin from feed into eggs was calculated. 相似文献
53.
Dennis Rubbenstroth Volker Schmidt Monika Rinder Marko Legler Victor Max Corman Peter Staeheli 《Veterinary microbiology》2014,168(2-4):318-323
Avian bornaviruses (ABV) are known to be the causative agent of proventricular dilatation disease (PDD) in parrots and their relatives (Psittaciformes). A broad range of ABV genotypes has been detected not only in psittacine birds, but also in other avian species including canary birds (Serinus canaria forma domestica) and Bengalese finches (Lonchura striata f. dom.), which are both members of the order songbirds (Passeriformes).During this study 286 samples collected from captive and wild birds of various passerine species in different parts of Germany were screened for the presence of ABV. Interestingly, only three ABV-positive samples were identified by RT-PCR. They originated from one yellow-winged pytilia (Pytilia hypogrammica) and two black-rumped waxbills (Estrilda troglodytes) from a flock of captive estrildid finches in Saxony. The ABV isolates detected here were only distantly related to ABV isolates found in passerine species in Germany and Japan and form a new genotype tentatively called ABV-EF (for “estrildid finches”). 相似文献
54.
Juan Mario Sanz‐Penella Jos Moiss Laparra Yolanda Sanz Monika Haros 《Cereal Chemistry》2012,89(5):223-229
The aim of this investigation was to study the influence of different bran proportions and particle sizes, addition of fungal phytase, and α‐amylase addition on bread quality and phytate levels, and how these treatments affect availability of iron to intestinal epithelial (Caco‐2) cells. Potential mineral contributions to dietary reference intakes and phytate‐to‐mineral molar ratios were also evaluated. Wheat bran supplementation significantly affected bread quality. Smaller bran particle size affected crumb firmness negatively, whereas the use of α‐amylase, in some cases in combination with phytase, could improve technological bread quality. The use of phytase in the formulation significantly reduced the level of phytates, and phytate hydrolysis also led to smaller bran particle size. Increasing the bran proportion used in the bread formulation increased the iron concentration in bread samples by 18.9%. Phytase addition proved to be a useful strategy to improve iron dialyzability; however, incomplete dephytinization still had an inhibitory effect on iron uptake, with the exception of samples formulated with 10% bran. The inhibitory effect of phytate could be predicted from the values of the phytate‐to‐iron ratios. Reduction of particle size did not improve iron availability or uptake by Caco‐2 cells. 相似文献
55.
56.
Kristina Bachteler Monika Riedel Nikolaus Merkt Wolfgang Schies Jutta Fröhlin Jens Wünsche 《Journal of plant nutrition》2015,38(6):839-853
Berry shrivel and bunch stem necrosis are the economically most important physiological disorders of grapevine. The nutritional status of the plant is considered as one of the main elicitors for the occurrence of these disorders. For foliar fertilization trials, two vineyards that had previously been affected by both diseases were selected in Southwest Germany, one with the variety ‘Zweigelt’ and one with Pinot Blanc. By the use of potassium, magnesium, and calcium foliar fertilizers, a rapid increase of different nutrients in the plants should be caused and the effects on the diseases observed. In 2010, no significant differences in the fertilization treatments were found for both varieties. In ‘Pinot Blanc’, significantly more berries were affected by berry shrivel in 2011 in plots treated with calcium fertilizer compared to those treated with potassium and magnesium. Plots with magnesium fertilizer showed significantly less berries affected by berry shrivel than the untreated control. 相似文献
57.
Monika MIERZWA-HERSZTEK Krzysztof GONDEK Altaf Hussain LAHORI Micha KOPE Ryszard MAZUREK Tomasz ZALESKI Tomasz GB Jerzy WIECZOREK 《土壤圈》2021,31(4):560-571
Composts are considered to be one of the best soil amendments. However, the effects of composts with added polymeric materials on soil physical,hydraulic, and micromorphological properties have not been widely discussed. Changes in soil physical properties influence the numerous services that soils provide. We studied the impacts of composts with the addition of three different polymers(F1–F3) produced from polyethylene and thermoplastic corn starch on the physical, hydraulic, and micromorphological properties of two soils, a Cambic Phaeozem and a Luvic Phaeozem. Applying composts with polymers had limited or no significant effect on soil bulk density and porosity, but increased the field water capacity by 18%–82% and 3%–6% and the plant-available water content by 15%–23% and 4%–17% for the Cambic Phaeozem and Luvic Phaeozem, respectively. The application of composts with polymers had a greater effect on the Cambic Phaeozem than on the Luvic Phaeozem. It was suggested that the use of modified composts led to changes in soil physical properties and micromorphological features and this effect was dependent on the compost application rate. Composts made with the addition of composite synthetic and natural material-derived polymers during composting were found to be a composite mixture that can be successfully used in agriculture. 相似文献
58.
Fallovo C Schreiner M Schwarz D Colla G Krumbein A 《Journal of agricultural and food chemistry》2011,59(8):4198-4207
The effect of three different nitrogen (N) supply forms differing in their ammonium-to-nitrate (NH(4):NO(3)) ratio (100% NH(4), 50% NH(4) + 50% NO(3), 100% NO(3)) under three different levels of daily photosynthetic active radiation (PAR) (low, 5.0; medium, 6.8; high, 9.0 mol m(-2) day(-1)) on a range of desirable health-promoting phytochemicals in Brassica rapa subsp. nipposinica var. chinoleifera and Brassica juncea was determined. The 100% NH(4) supply under medium PAR levels led to the highest concentration of glucosinolates based on a low nitrogen/sulfur ratio as well as high levels of carotenoids in the leaves of both Brassica species. However, the 100% NH(4) supply under low and medium PAR levels resulted in low concentrations of flavonoids based on high N concentration in the leaves. Thus, the data provided here have strong implications for crop management strategies aimed at optimizing both the concentration and composition of a range of phytochemicals. 相似文献
59.
60.
Monika Vilkienė Dalia Ambrazaitienė Danutė Karčauskienė Zenonas Dabkevičius 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2016,66(8):641-646
ABSTRACTMineralization is the main organic matter conversion process, which leads not only to preservation of organic matter in the soil but also to its sequestration. Soil organic matter has equal value as mineral part if we want to improve soil quality or increase the yield. Because of intensive farming, irresponsible use of mineral fertilizers and natural factors, soil organic matter is decreasing. To counteract this process, different soil-friendly management practices and techniques, such as shallow tillage, no-tillage or direct drilling and application of additional organic matter are used. The objective of the present study was to assess the changes in the intensity of soil organic matter mineralization as influenced by primary soil tillage of different intensity in combination with organic matter incorporation. Long-term studies showed that land management practices differentiated the soil into two layers: upper (0–10?cm) layer containing more moisture and nutrients and lower (10–20?cm) layer comprising less moisture and nutrients. The conditions of aeration in the arable soil layer did not change under the effect of ploughing. In this soil, the rate of mineralization was lower than that in the ploughless tillage treatment. The most active mineralization of soil organic matter in the ploughless tillage treatment occurred in the autumn period, when high level of rainfall promoted the loss of nutrients from the topsoil layer. 相似文献