全文获取类型
收费全文 | 221篇 |
免费 | 4篇 |
专业分类
林业 | 10篇 |
农学 | 9篇 |
基础科学 | 10篇 |
70篇 | |
综合类 | 22篇 |
农作物 | 8篇 |
水产渔业 | 11篇 |
畜牧兽医 | 61篇 |
园艺 | 7篇 |
植物保护 | 17篇 |
出版年
2022年 | 5篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 3篇 |
2013年 | 12篇 |
2012年 | 14篇 |
2011年 | 17篇 |
2010年 | 13篇 |
2009年 | 14篇 |
2008年 | 32篇 |
2007年 | 16篇 |
2006年 | 10篇 |
2005年 | 16篇 |
2004年 | 12篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 3篇 |
2000年 | 8篇 |
1999年 | 1篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1979年 | 2篇 |
1976年 | 1篇 |
排序方式: 共有225条查询结果,搜索用时 15 毫秒
71.
van der Sluis AA Dekker M Skrede G Jongen WM 《Journal of agricultural and food chemistry》2004,52(10):2840-2848
There is a great interest in food components that possess possible health-protecting properties, as is the case with flavonoids. Previous research showed that conventional apple juice processing resulted in juices poor in flavonoids and with a low antioxidant activity. This paper shows that it is possible to improve flavonoid content in juice and its antioxidant activity by applying an alcoholic extraction either on the pulp or on the pomace. The levels of flavonoids and chlorogenic acid in enriched juice were between 1.4 (chlorogenic acid) and 9 (quercetin glycosides) times higher than in conventional apple juice. In enriched juice the antioxidant activity was 5 times higher than in conventional apple juice, with 52% of the antioxidant activity of the originating fruits present. The novel processing method had similar effects for three apple cultivars tested (Elstar, Golden Delicious, and Jonagold). The taste and color of enriched juice were different from those of conventional juice. 相似文献
72.
73.
An Integrative Approach to Value‐Added Planning: From Community Needs to Local Authority Revenue 下载免费PDF全文
The concept of value‐added planning (as part of the Valuing Attractive Landscapes in the Urban Economy, INTERREG IVB North West Europe Project) is introduced in this paper to facilitate integrative planning, focusing on the benefits that use and non‐use green spaces can provide to an urban area. The aim is to stress the need to plan for, and protect, green spaces in urban areas by determining the economic values connected to the green spaces and relate that values to community benefit and local authority revenue. The paper identifies tools that can be used to determine the economic value of green spaces based on the environmental, social, and economic benefits. The first section (value) refers to the social value of green spaces as determined from the public perspective and introduces the workbench method as a tool to assist with participatory planning and capturing of the social benefits of green spaces. The second section (added) refers to the environmental benefits of green spaces and, by means of the Green Credit Tool, introduces ways to ensure the protection of the green resources in an area. The final section (planning) refers to the economic benefit of green space, bringing use values and non‐use values of green spaces together. The paper concludes with an integrative framework for value‐added planning, incorporating all the tools presented in the paper, capturing the social, environmental, and economic benefits of green spaces and relating it to community benefit and local authority revenue. 相似文献
74.
Consumer acceptance of cultured meat is expected to depend on a wide diversity of determinants ranging from technology-related perceptions to product-speciifc expectations, and including wider contextu... 相似文献
75.
76.
77.
Steukers L Vandekerckhove AP Van den Broeck W Glorieux S Nauwynck HJ 《Veterinary research》2011,42(1):33
ABSTRACT: In general, members of the Alphaherpesvirinae use the epithelium of the upper respiratory and/or genital tract as a preferential site for primary replication. Bovine herpesvirus type 1 (BoHV-1) may replicate at both sites and cause two major clinical entities designated as infectious bovine rhinotracheitis (IBR) and infectious pustular vulvovaginitis/balanoposthitis (IPV/IPB) in cattle. It has been hypothesized that subtype 1.1 invades preferentially the upper respiratory mucosa whereas subtype 1.2 favors replication at the peripheral genital tract. However, some studies are in contrast with this hypothesis. A thorough study of primary replication at both mucosae could elucidate whether or not different BoHV-1 subtypes show differences in mucosa tropism. We established bovine respiratory and genital organ cultures with emphasis on maintenance of tissue morphology and viability during in vitro culture. In a next step, bovine respiratory and genital mucosa explants of the same animals were inoculated with several BoHV-1 subtypes. A quantitative analysis of viral invasion in the mucosa was performed at 0 h, 24 h, 48 h and 72 h post inoculation (pi) by measuring plaque latitude and penetration depth underneath the basement membrane. All BoHV-1 subtypes exhibited a more profound invasion capacity in respiratory tissue compared to that in genital tissue at 24 h pi. However, at 24 h pi plaque latitude was found to be larger in genital tissue compared to respiratory tissue and this for all subtypes. These similar findings among the different subtypes take the edge off the belief of the existence of specific mucosa tropisms of different BoHV-1 subtypes. 相似文献
78.
Paul Vanhaecke Lieven De Vrieze Wim Tackaert Patrick Sorgeloos 《Journal of the World Aquaculture Society》1990,21(4):257-262
Decapsulated Arremia cysts have been evaluated as a direct food source for larvae of the carp Cyprinus carpio L. All decapsulated cyst diets gave excellent survival of carp larvae during the first two weeks of culturing. Unlike traditionally brine-stored decapsulated cysts, dried Artemia embryos provided growth results comparable to those obtained with freshly hatched Artemia nauplii. Furthermore, except for Artemia embryos that lost their hatchability after long-term storage in air, several other inactivation treatments, simulating improper harvesting and processing of cysts, did not produce a significant decrease in the nutritional quality of the decapsulated cysts.
Using decapsulated cysts 89 a direct food source for carp larvae, instead of nauplii, the quantity of cysts needed can be reduced by about 25% to 35% after one and two weeks of culturing, respectively. Moreover, the use of decapsulated cysts advances the possible commercialition of poor-hatching and less expensive cyst products for culture of carp larvae. 相似文献
Using decapsulated cysts 89 a direct food source for carp larvae, instead of nauplii, the quantity of cysts needed can be reduced by about 25% to 35% after one and two weeks of culturing, respectively. Moreover, the use of decapsulated cysts advances the possible commercialition of poor-hatching and less expensive cyst products for culture of carp larvae. 相似文献
79.
Peter K. Jensen Yutaka Matsuno Wim van der Hoek Sandy Cairncross 《Irrigation and Drainage Systems》2001,15(2):117-128
The standards for irrigation water qualityare currently provided by global andnational guidelines that are mostly basedon the assumption that threshold valuescould be applied to protect crops. Thisapproach can create problems for a largelyunrecognized group of people who make useof irrigation water for non-agriculturalpurposes. At the same time, increasingwater scarcity will lead to the need forrecycling of water in irrigated riverbasins, and the use of low qualityirrigation water. Apart from hazards ofhigh pollutant levels, a sustainabilitycriterion has to be included in the waterquality guidelines to account for long-termlow-level application of certain pollutantsthat can accumulate in the environment.Using the example of cadmium, it is arguedthat the current guidelines need to berevised and should take local factors andfuture developments into account. 相似文献
80.
Ex-post evaluation of erosion control measures in southern Mali 总被引:3,自引:0,他引:3
As part of an impact study of a soil and water conservation (SWC) project in southern Mali, the effect of erosion control measures on soil erosion was evaluated. In one village, a baseline situation from 1988 was compared with the situation in 2003, after farmers had installed stone rows, live fences and grass strips, and had started cultivating across to the slope. This comparison showed a spectacular decrease in gully volume in cultivated fields of 87%, from 58 to 8 m3 ha−1. Estimated annual soil loss decreased with 77% from 42 to 10 t ha−1 year−1. However, baseline data on erosion gullies were not available for other villages. In the absence of baseline data, a simple ‘with–without’ comparison does not allow a correct evaluation because farmers install erosion control measures especially in fields with more erosion. Two alternative methods were used: a reconstructed baseline and a virtual time series. Using the reconstructed baseline, looking not only at active gullies but also at (partly) reclaimed gullies, we concluded that line interventions, gully interventions, and a combination of both, reduced the proportion of active gullies by 48%, 47% and 70%, respectively. Using a virtual time series, comparing erosion in fields with erosion control measures installed in different years, we concluded that erosion gradually decreased by 50% during the 3 years after installation of erosion control measures. In a separate study, we found a positive effect of gully interventions and sowing across to the slope in reducing sheet erosion. A reduction of the slope of the sowing direction by 1% reduced the cover of runoff deposit of coarse sand with 8%. Although a documented baseline is preferred, both a reconstructed baseline and a virtual time series are useful tools and make ex-post evaluations more relevant than a simple with–without comparison. 相似文献