全文获取类型
收费全文 | 1675篇 |
免费 | 49篇 |
国内免费 | 56篇 |
专业分类
林业 | 178篇 |
农学 | 136篇 |
基础科学 | 9篇 |
100篇 | |
综合类 | 725篇 |
农作物 | 165篇 |
水产渔业 | 42篇 |
畜牧兽医 | 199篇 |
园艺 | 204篇 |
植物保护 | 22篇 |
出版年
2024年 | 5篇 |
2023年 | 22篇 |
2022年 | 20篇 |
2021年 | 28篇 |
2020年 | 28篇 |
2019年 | 37篇 |
2018年 | 10篇 |
2017年 | 39篇 |
2016年 | 47篇 |
2015年 | 55篇 |
2014年 | 77篇 |
2013年 | 65篇 |
2012年 | 80篇 |
2011年 | 142篇 |
2010年 | 113篇 |
2009年 | 134篇 |
2008年 | 133篇 |
2007年 | 128篇 |
2006年 | 120篇 |
2005年 | 104篇 |
2004年 | 59篇 |
2003年 | 53篇 |
2002年 | 34篇 |
2001年 | 27篇 |
2000年 | 32篇 |
1999年 | 26篇 |
1998年 | 23篇 |
1997年 | 27篇 |
1996年 | 21篇 |
1995年 | 16篇 |
1994年 | 20篇 |
1993年 | 14篇 |
1992年 | 7篇 |
1991年 | 12篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1977年 | 1篇 |
1963年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有1780条查询结果,搜索用时 15 毫秒
51.
Consumer perception versus scientific evidence of farmed and wild fish: exploratory insights from Belgium 总被引:2,自引:2,他引:0
Wim Verbeke Isabelle Sioen Karen Brunsø Stefaan De Henauw John Van Camp 《Aquaculture International》2007,15(2):121-136
The increasing number of marketable fish being supplied from aquaculture is a response to the increasing demand for healthy
food and is filling the gap left by depleting natural fish stocks. Little is known about the awareness and perception of the
consumer in terms of farmed fish versus fish from capture fisheries. The consumer's subjective point of view is of overriding
importance for the production system and product acceptance as well as for future market success. In this paper consumer perception
in Belgium is explored and compared against scientific evidence of farmed versus wild fish. Primary data were collected through
a consumer survey (April 2003) and focus group discussions (May 2004) with Belgian consumers. The majority of the consumer
sample reported no perceived differences between farmed versus wild fish. However, mean perception scores were slightly in
favour of wild fish on the attributes taste, health and nutritious value, in particular among consumers aged 55 years and
older. The availability of farmed fish was perceived to be better than that of wild fish, while the consumer's perception
of safety did not differ between farmed and wild fish. The focus group discussions indicated that consumers’ opinions and
beliefs about farmed fish are mainly based on emotion and image transfer from intensive terrestrial livestock production rather
than on awareness and factual knowledge of aquaculture.
相似文献
John Van CampEmail: |
52.
对3种野生草本植物进行了坪用栽培,详细观察研究了3种植物的物候期表现、生长习性和绿化效果。试验表明:扁蓄极耐严寒,对干旱、水涝、高温等逆境适应性强,抗污染能力强,保持绿色时间长,发挥绿化功能快,不择土壤,种植管理方便,可作为园林草坪绿化的优良地被植物。 相似文献
53.
54.
55.
We have proposed a new interpretation of fruit softening. This was accomplished by generating a hypothesis that probabilities of decay of fruit structure obey the Weibull probabilistic model that has been used in the field of reliability engineering. The elasticity of individual kiwifruit after harvest was continually and nondestructively measured until decomposition by using a laser Doppler vibrometer. The obtained decreasing pattern of elasticity of individual fruit was complex, diverse, and inhomogeneous. Nonetheless, it was satisfactorily explained by a tandem combination of 2 Weibull models involving 4 types of parameters: “shape” related to probability; “scale,” to velocity of decay; “location,” to time lag; and “mixing ratio,” to contribution of the 2 models. Averages of location, shape, and mixing ratio parameters obtained by the measurement of 33 fruit were significantly different between the 2 models, but the scale parameter was not. The results suggested that the complex softening patterns of individual kiwifruit could be described using the tandem model of Weibull distribution, and that the softening process of kiwifruit consisted of at least 2 independent decay phases that are characterized by 2 of 5 parameters: location and mixing ratio. Commencement of the first decay phase could be caused by ethylene treatment after harvest, and the second one spontaneously triggered after a certain time lag. 相似文献
56.
芭蕉属野生种的地理分布 总被引:1,自引:0,他引:1
芭蕉属起源于热带亚热带区域,对芭蕉属野生种质资源的研究始于20世纪40年代。通过检索INIBAP的多个数据库和相关文献,归纳整理出芭蕉属野生种的分布规律,为野生蕉的种质资源保存、利用以及品种鉴定提供一定的理论依据。经分析,目前已经报道的芭蕉属共有52个野生种,其中真芭蕉组(Eumusa)11个,观赏蕉组(Rhodochlamys)9个,澳蕉组(Australimusa)13个,红花蕉组(Callimusa)18个,不确定组(Incertae sedis)1个。马来西亚、印度尼西亚、巴布亚新几内亚、印度和中国均分布有不同的3组芭蕉属野生种,但马来西亚和印度分布的种数最多,各分布有15种,约占总数的29%,可能是芭蕉属野生种的多样性中心。 相似文献
57.
一氧化氮对猕猴桃果实营养品质和活性氧代谢的影响 总被引:2,自引:0,他引:2
分别用10、20和30μL.L-1一氧化氮(NO)气体熏蒸猕猴桃果实,研究NO对采后徐香猕猴桃(Actinidia chi-nensis Planch.cv.Xuxiang)的营养品质变化和活性氧代谢的影响。结果表明,20μL.L-1 NO处理后的猕猴桃果实含有较低的可溶性固形物和较高的可滴定酸、维生素C,且果实中丙二醛和超氧自由基质量分数低于其他体积分数的NO熏蒸处理(10和30μL.L-1 NO)。20μL.L-1 NO处理降低了猕猴桃果实中LOX活性,延缓了猕猴桃果实采后期间CAT活性的降低,显著提高了猕猴桃果实SOD和POD活性,且显著降低了猕猴桃果实中过氧化氢的质量分数。20μL.L-1 NO气体熏蒸保持了猕猴桃中较高的叶绿素、类胡萝卜素以及维生素E的质量分数。 相似文献
58.
59.
60.