首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   98篇
  免费   5篇
林业   10篇
农学   4篇
  22篇
综合类   11篇
农作物   9篇
畜牧兽医   39篇
植物保护   8篇
  2020年   2篇
  2019年   3篇
  2018年   2篇
  2017年   2篇
  2016年   3篇
  2015年   5篇
  2014年   6篇
  2013年   1篇
  2012年   5篇
  2011年   7篇
  2010年   7篇
  2009年   5篇
  2008年   4篇
  2007年   9篇
  2006年   5篇
  2005年   5篇
  2004年   3篇
  2003年   4篇
  2002年   2篇
  2001年   2篇
  1998年   1篇
  1996年   1篇
  1995年   1篇
  1994年   3篇
  1992年   2篇
  1991年   1篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
  1985年   3篇
  1982年   1篇
  1981年   1篇
  1974年   1篇
  1969年   1篇
  1967年   1篇
排序方式: 共有103条查询结果,搜索用时 15 毫秒
71.
Field surveys were carried out in the main peach-growing areas of Lebanon to assess the presence and distribution of viruses and viroids in commercial orchards. Field inspections were made in spring and summer 2000 to observe symptoms of virus and viroid diseases respectively. In total, 950 trees in 95 commercial plantings from three different regions of Lebanon (Bekaa Valley, Mount Lebanon and north Lebanon) were surveyed and sampled. Immunoenzymatic tests (DAS-ELISA) were used to ascertain the presence of the following: Prunus necrotic ring spot ilarvirus (PNRSV), Prune dwarf ilarvirus (PDV), Apple mosaic ilarvirus (ApMV), Apple chlorotic leaf spot trichovirus (ACLSV), Plum pox potyvirus (PPV), Tomato ringspot nepovirus (ToRSV) and Strawberry latent ringspot nepovirus (SLRSV). Peach latent mosaic pelamoviroid (PLMVd) and Hop stunt hostuviroid (HSVd) were identified by molecular hybridization. About 25% of the tested samples were infected by one or more viruses. In particular, the prevailing virus was PNRSV (61.2% of infection), followed by ACLSV (27.1%), PDV (22.4%) and ApMV (2.1%). Mixed infections were about 13%. ToRSV, SLRSV and PPV were not found. HSVd was apparently absent, whereas PLMVd was identified in 34% of the samples examined. This viroid prevailed in certain areas of Mount Lebanon in both native and foreign cultivars.  相似文献   
72.
73.
Plant Foods for Human Nutrition - Disturbed advanced glycation end products (AGEs)-oxidative stress axis is strongly linked to vascular complications observed in diabetes and other metabolic...  相似文献   
74.
75.
The characterisation of the wheat endosperm by mechanical tests of compression highlighted a relation between the rupture energy and the elasticity modulus for different varieties of wheat; this relation allows us to distinguish mealy and vitreous endosperms. An approach based on the micromechanics of cohesive granular materials is used to analyse these experimental results. A geometrical model of the wheat endosperm made of grains linked by cohesive bonds is proposed. We introduced two parameters, the first one α represents the percentage of active bonds (bonds where the stiffness and strength are non-zero), and the second one β represents the threshold of the bond's rupture. The parameter β can be related to the cross-section of the bond. This model successfully describes the mechanical tests on the wheat endosperm. The comparison with the experimental tests makes it possible to clearly differentiate vitreous wheats and mealy wheats and then attribute this property to the parameter β. The model shows the same tendency as regards the evolution of the rupture energy and the elastic modulus with the parameter α. The modelling of endosperm by the mechanics of cohesive granular media provides a new theoretical framework to interpret the rheology of endosperm. This approach allows us to connect this rheology to the mechanical actions at the scale of the granules.  相似文献   
76.
Human UBIAD1 localizes to mitochondria and converts vitamin K(1) to vitamin K(2). Vitamin K(2) is best known as a cofactor in blood coagulation, but in bacteria it is a membrane-bound electron carrier. Whether vitamin K(2) exerts a similar carrier function in eukaryotic cells is unknown. We identified Drosophila UBIAD1/Heix as a modifier of pink1, a gene mutated in Parkinson's disease that affects mitochondrial function. We found that vitamin K(2) was necessary and sufficient to transfer electrons in Drosophila mitochondria. Heix mutants showed severe mitochondrial defects that were rescued by vitamin K(2), and, similar to ubiquinone, vitamin K(2) transferred electrons in Drosophila mitochondria, resulting in more efficient adenosine triphosphate (ATP) production. Thus, mitochondrial dysfunction was rescued by vitamin K(2) that serves as a mitochondrial electron carrier, helping to maintain normal ATP production.  相似文献   
77.
Malt is known to have an impact on beer flavor stability mainly due to the presence of antioxidants. In this study, five barley varieties were malted at industrial and micro scale, and quality parameters of the resulting malts were measured (diastatic power, friability, beta-glucan content, antiradical power, reducing power, lipoxygenase activity, and nonenal potential) and correlated with the sensory data obtained for the corresponding fresh and forced aged beers. A statistical strategy using multiple linear regressions was applied to explore relationships between the malt chemical parameters and beer sensory data, showing antiradical power as the major contribution of malt to beer flavor stability. Additionally, the measured antiradical power, which is well correlated with the polyphenolic content, was found to be very similar for malt and barley, emphasizing the key role of barley endogenous polyphenols.  相似文献   
78.
During the period December 1998-May 2000, 900 local goats slaughtered at the Irbid Abattoir (northern Jordan) were examined for the larval instars of Przhevalskiana silenus. Of 900 goats, 10% (95% CI: 9,13) were infested with P. silenus larvae. Only the second and third larval instars were seen. A multiple-regression analysis (with the error variance described by the negative-binomial function) suggested that infestation depended on the month of sampling, and that infestation with live larvae was associated with a poorer carcass. The percentage of infested goats and the mean monthly total number of larvae per goat peaked in samples taken in the autumn and winter. Larval numbers were highly aggregated: most animals had no larvae but the maximum was 69. Analysis of the pattern of aggregation suggested that the best model fit was one in which the larvae counts per goat varied with the monthly prevalence.  相似文献   
79.
Corridors increase plant species richness at large scales   总被引:1,自引:0,他引:1  
Habitat fragmentation is one of the largest threats to biodiversity. Landscape corridors, which are hypothesized to reduce the negative consequences of fragmentation, have become common features of ecological management plans worldwide. Despite their popularity, there is little evidence documenting the effectiveness of corridors in preserving biodiversity at large scales. Using a large-scale replicated experiment, we showed that habitat patches connected by corridors retain more native plant species than do isolated patches, that this difference increases over time, and that corridors do not promote invasion by exotic species. Our results support the use of corridors in biodiversity conservation.  相似文献   
80.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号