全文获取类型
收费全文 | 280篇 |
免费 | 9篇 |
专业分类
林业 | 20篇 |
农学 | 14篇 |
基础科学 | 2篇 |
110篇 | |
综合类 | 12篇 |
农作物 | 27篇 |
水产渔业 | 10篇 |
畜牧兽医 | 62篇 |
园艺 | 10篇 |
植物保护 | 22篇 |
出版年
2022年 | 1篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 3篇 |
2017年 | 8篇 |
2016年 | 9篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 20篇 |
2012年 | 17篇 |
2011年 | 32篇 |
2010年 | 16篇 |
2009年 | 12篇 |
2008年 | 30篇 |
2007年 | 14篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 13篇 |
2003年 | 17篇 |
2002年 | 9篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有289条查询结果,搜索用时 32 毫秒
281.
Luigi Milella Danilo Saluzzi Mauro Lapelosa Giuseppe Bertino Piero Spada Ivana Greco Giuseppe Martelli 《Genetic Resources and Crop Evolution》2006,53(8):1715-1720
Random-amplified polymorphic DNA (RAPD) markers were used to evaluate genetic variability among populations of an Italian
strawberry ecotype, and to determinate genetic relationships between genotypes and their putative ancestor. A total of 65
selections and one cultivar ‘Madame Moutot’ (MM), were analysed to evaluate genetic variability present in Etna mountain area
and to confirm as MM was one of the cultivars that originated the ecotype. A total of 222 RAPD markers was obtained using
16 decamer primers and 6 longer primers, 90.8% of the markers obtained by selected primers resulted polymorphic at least within
analysed genotypes. RAPDs were used to calculate genetic similarity coefficients and to generate dendrograms representing
genetic relationships among genotypes analysed. Cluster analysis displays as RAPD polymorphisms were able to characterize
the genotype variability among closely related groups. The data show as MM could be considered the ancestral genotypes introduced
in that area. The results obtained confirm that RAPD markers could be used as reliable markers to perform phylogenetic studies
in Fragaria×ananassa Duch. ex Rozier.
Giuseppe Bertino and Piero Spada - Coauthor involved in genotype selection and field management 相似文献
282.
283.
Flamini G Bader A Cioni PL Katbeh-Bader A Morelli I 《Journal of agricultural and food chemistry》2004,52(3):572-576
Pistacia palaestina Boiss. (Pistacia terebinthus L. var. palaestina (Boiss.) Engl.) is a medicinal and foodstuff plant. The ripe fruits are used largely in the Middle East as a component of the so-called Zaatar, a mix of aromatic and food plants. Results of GC and GC-MS analyses of the essential oils of leaves, galls produced by Baizongia pistaciae (L.), and ripe and unripe fruits of Pistacia palaestinaBoiss. collected in Jordan are reported. Both qualitative and quantitative differences between different parts of the plant were observed. The oil was rich in monoterpenes, and the main constituents were alpha-pinene (63.1%) and myrcene (13.3%) in the leaves and alpha-pinene (49.4%), sabinene (22.8%), and limonene (8.1%) in the galls. (E)-Ocimene (33.8-41.3%), sabinene (20.3-24.1%), and (Z)-ocimene (3.8-13.0%) were the main ones in both unripe and ripe fruits. Sesquiterpenes have been detected in small quantities in leaves and fruits and in trace amounts in galls. 相似文献
284.
Servillo L Giovane A Balestrieri ML Cautela D Castaldo D 《Journal of agricultural and food chemistry》2011,59(1):274-281
The content of proline and various compounds deriving from its metabolism (4-hydroxy-L-proline, N-methyl-L-proline, N,N-dimethylproline, and 4-hydroxy-L-prolinebetaine) was determined in fruits and seeds of Bergamot (Citrus bergamia Risso et Poit), growing in the Calabria region (South Italy). A HPLC-ESI-tandem mass spectrometry method, which allowed rapid determination of L-proline, 4-hydroxy-L-proline, N-methyl-L-proline, N,N-dimethylproline, and 4-hydroxy-L-prolinebetaine in juice and extracts of bergamot fruit with minimum sample preparation and short analysis time (about 10 min), is presented. Proline and 4-hydroxy-L-proline levels in the samples were also determined by HPLC analysis with fluorescence detection and the results compared to those obtained with HPLC-ESI-tandem mass spectrometry. For the first time, the presence of N-methyl-L-proline and 4-hydroxy-L-prolinebetaine in the fruits of a plant of the Citrus genus is reported. 相似文献
285.
Gambuti A Strollo D Ugliano M Lecce L Moio L 《Journal of agricultural and food chemistry》2004,52(18):5747-5751
The concentrations of trans-resveratrol, (+)-catechin, (-)-epicatechin, and quercetin were evaluated by means of high-performance liquid chromatography-diode array detection in red wines obtained from Aglianico, Piedirosso, and Nerello Mascalese grapes. The trans-resveratrol and epicatechin concentrations did not differ significantly between experimental wines. The concentration of quercetin in Nerello Mascalese wines was more than twice that observed in Aglianico and Piedirosso wines. Nerello Mascalese wines also significantly differed from other wines in the (+)-catechin content, which was significantly higher than those found in the other two wines. During maceration, the maximum extraction of trans-resveratrol was reached after 12 days for Aglianico and Piedirosso, after which a decline was observed. On the contrary, in the case of Nerello Mascalese, the concentration of trans-resveratrol increased steadily throughout the whole maceration process. After 2 days of maceration, the maximum concentration of quercetin was observed in Aglianico must, whereas the maximum quercetin extraction was reached after 12 days for Piedirosso and 17 days for Nerello Mascalese. The maximum levels of (+)-catechin and (-)-epicatechin were generally observed after 12 days of maceration for all wines, although a decline of (-)-epicatechin occurred after maximum extraction in Aglianico and Piedirosso wines. Following marc pressing, a significant increase in the concentration of trans-resveratrol for Aglianico, (+)-catechin and (-)-epicatechin for Piedirosso, and (-)-epicatechin for Nerello Mascalese was observed. 相似文献
286.
287.
What's in an index? Comparing the ecological information provided by two indices to assess the status of coralligenous reefs in the NW Mediterranean Sea 下载免费PDF全文
288.
Carmen Cianfrani Gwenaëlle Le Lay Luigi Maiorano Héctor F. Satizábal Anna Loy Antoine Guisan 《Biological conservation》2011,(8):2068-2080
Climate change has created the need for new strategies in conservation planning that account for the dynamics of factors threatening endangered species.Here we assessed climate change threat to the European otter, a flagship species for freshwater ecosystems, considering how current conservation areas will perform in preserving the species in a climatically changed future. We used an ensemble forecasting approach considering six modelling techniques applied to eleven subsets of otter occurrences across Europe. We performed a pseudo-independent and an internal evaluation of predictions. Future projections of species distribution were made considering the A2 and B2 scenarios for 2080 across three climate models: CCCMA-CGCM2, CSIRO-MK2 and HCCPR HADCM3. The current and the predicted otter distributions were used to identify priority areas for the conservation of the species, and overlapped to existing network of protected areas.Our projections show that climate change may profoundly reshuffle the otter’s potential distribution in Europe, with important differences between the two scenarios we considered. Overall, the priority areas for conservation of the otter in Europe appear to be unevenly covered by the existing network of protected areas, with the current conservation efforts being insufficient in most cases. For a better conservation, the existing protected areas should be integrated within a more general conservation and management strategy incorporating climate change projections. Due to the important role that the otter plays for freshwater habitats, our study further highlights the potential sensitivity of freshwater habitats in Europe to climate change. 相似文献
289.
The Mediterranean region has been regarded as a critical hotspot for desertification due to the impact of soil degradation, the land‐use changes and the climate variations. Few large‐scale studies have been devoted to analyse trends in land sensitivity to desertification in the northern Mediterranean basin. The present paper contributes to this deserving issue by quantifying the level of land sensitivity to desertification in Italy at seven points between 1960 and 2010 at a fine spatial scale. The approach used followed the Environmentally Sensitive Area scheme that assesses changes in four key themes (climate, soil, vegetation and land management) related to land degradation processes. Italian land was classified into four levels of sensitivity to desertification (non‐affected, potentially affected, fragile and critical) according to the Environmentally Sensitive Area framework. Interestingly, although land surface area classified as ‘fragile’ and ‘critical’ grew homogeneously in Italy between 1960 and 1990, the increase observed in the most recent time period was spatially clustered and contributed to reverse the polarisation in ‘structurally vulnerable’ and ‘non‐affected’ regions observed in Italy. The paper discussed these trends in the light of socioeconomic changes that occurred in Italy after World War II. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献