全文获取类型
收费全文 | 474篇 |
免费 | 26篇 |
专业分类
林业 | 41篇 |
农学 | 24篇 |
基础科学 | 3篇 |
94篇 | |
综合类 | 34篇 |
农作物 | 38篇 |
水产渔业 | 52篇 |
畜牧兽医 | 168篇 |
园艺 | 7篇 |
植物保护 | 39篇 |
出版年
2024年 | 1篇 |
2023年 | 7篇 |
2022年 | 15篇 |
2021年 | 41篇 |
2020年 | 26篇 |
2019年 | 31篇 |
2018年 | 16篇 |
2017年 | 22篇 |
2016年 | 24篇 |
2015年 | 18篇 |
2014年 | 28篇 |
2013年 | 36篇 |
2012年 | 41篇 |
2011年 | 31篇 |
2010年 | 23篇 |
2009年 | 16篇 |
2008年 | 16篇 |
2007年 | 17篇 |
2006年 | 19篇 |
2005年 | 17篇 |
2004年 | 12篇 |
2003年 | 16篇 |
2002年 | 13篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有500条查询结果,搜索用时 0 毫秒
381.
Diego Lijavetzky M. Carolina Martínez Fernando Carrari H. Esteban Hopp 《Euphytica》2000,112(2):125-135
One of the most important agronomic problems in the production of sorghum [Sorghum bicolor (L.) Moench] in humid climates is pre-harvest sprouting (PHS). A molecular linkage map was developed using 112molecular markers
in an F2 mapping population derived from a cross between IS 9530 (high resistance to PHS) and Redland B2 (susceptible to PHS). Two
year phenotypic data was obtained. By means of interval mapping analysis, two significant QTL were detected in two different
linkage groups with LOD scores of 8.77and 4.39. Each of these two QTL individually explained approximately 53% of the phenotypic
variance, but together, in a two-QTL model, they explained 83% of the phenotypic variance with a LOD score of 12.37.These
results were corroborated by a one-way ANOVA in which the four flanking markers of the most likely QTL positions displayed
highly significant values in theF-test, and significant variation in trait expression was associated with marker genotypic classes. The four markers with highest
effect in the one-way ANOVA were also detected in the second year replication of the F2 population, and significant genotype × environment interactions was observed. The putative relationship between PHS resistance
in sorghum and the maize Vp1 gene is also discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
382.
Diego Valderrama Sivaraman Iyemperumal M. Krishnan 《Aquaculture Economics & Management (Blackwell Science)》2013,17(4):369-394
Shrimp farming in India has developed at an uneven pace since export-oriented production began in the early 1990s. The introduction of Penaeus vannamei in 2009 along with disease-related production declines in competing Asian nations has led to a remarkable expansion in recent years. It is clear that the long-term success of Indian shrimp farming will continue to rely on the widespread adoption of Better Management Practices (BMPs). A two-round stakeholder Delphi survey was conducted in 2012 to elicit views and build consensus on the relative importance of a comprehensive set of BMPs covering most aspects of shrimp farming production. While the vast majority of BMPs were considered important, respondents placed greater emphasis on those BMPs aimed at improving production efficiency. Also, BMPs focused on overall outcomes were ranked higher than those placing specific restrictions on input usage. Results also yielded interesting policy implications on BMPs that are yet to be widely adopted such as distance between farms and construction of effluent treatment systems. 相似文献
383.
Yanina A TORRES Carlos A BUSSO Oscar A MONTENEGRO Leticia ITHURRART Hugo D GIORGETT Gustavo RODRíGUEZ Diego BENTIVEGNA Roberto E BREVEDAN Osvaldo A FERNáNDEZ María M MUJICA Sandra S BAIONI José ENTíO María N FIORETTI Guillermo TUCAT 《干旱区科学》2014,(2):195-204
Pappophorum vaginatum is the most abundant C4perennial grass desirable to livestock in rangelands of northeastern Patagonia,Argentina.We hypothesized that(1)defoliation reduce net primary productivity,and root length density and weight in the native species,and(2)root net primary productivity,and root length density and weight,are greater in P.vaginatum than in the other,less desirable,native species(i.e.,Aristida spegazzinii,A.subulata and Sporobolus cryptandrus).Plants of all species were either exposed or not to a severe defoliation twice a year during two growing seasons.Root proliferation was measured using the cylinder method.Cylindrical,iron structures,wrapped up using nylon mesh,were buried diagonally from the periphery to the center on individual plants.These structures,initially filled with soil without any organic residue,were dug up from the soil on 25April 2008,after two successive defoliations in mid-spring 2007.During the second growing season(2008–2009),cylinders were destructively harvested on 4 April 2009,after one or two defoliations in midand/or late-spring,respectively.Roots grown into the cylinders were obtained after washing the soil manually.Defoliation during two successive years did reduce the study variables only after plants of all species were defoliated twice,which supported the first hypothesis.The greater root net primary productivity,root length density and weight in P.vaginatum than in the other native species,in support of the second hypothesis,could help to explain its greater abundance in rangelands of Argentina. 相似文献
384.
Beak microstructure analysis as a tool to identify potential rearing stress for Octopus vulgaris paralarvae 下载免费PDF全文
Rita Melo Franco‐Santos Catalina Perales‐Raya Eduardo Almansa Marleen De Troch Diego Garrido 《Aquaculture Research》2016,47(9):3001-3015
Octopus vulgaris is a viable candidate for commercial aquaculture, but rearing procedures might stress individuals and result in diminished growth and survival. This study investigated the relationship between possible stress sources (tank transposition and syphoning) when rearing O. vulgaris paralarvae and the deposition pattern of growth increments in their beak microstructure. Light intensity at the facility was heterogeneous, and accounted for with an experimental design consisting of blocks without replicates. Growth and survival were estimated and possible effects of handling were tested for both parameters. Increments and stress marks were counted in 120 paralarval upper jaws (UJ), and the number of UJs with a mark on the day of stress application (day 8) was quantified. Differences in light intensity, diet quantity and total number of marks in the UJ were also compared between treatments. Growth and survival were statistically similar between treatments, although the control treatment showed a tendency for higher survival rates. Age at first increment deposition coincided with day 1 of experiment, and a 1 increment day?1 deposition rate was validated for the experiment duration. The number of stress marks was significantly different between the control and other treatments, indicating that handling might cause stress and that marks can be used as a biomarker for stress, although the occurrence of stress marks on day 8 was not significantly different. Light intensity and diet might have also been relevant stressors and confounded the results. The results herein presented are important for improving rearing conditions for O. vulgaris paralarvae. 相似文献
385.
Diego Gomes Trindade Nelson de Almeida de Gouveia Niedja Luana da Costa da Mescouto Hanna Tereza Garcia de Sousa Moura Ualerson Iran Peixoto da Silva Bianca Bentes 《Fisheries Oceanography》2024,33(2):e12662
The aim of this study was to analyze the effects of climate and marine variability on the catches of Lutjanus purpureus in three sectors of the Amazon Continental Shelf. Remote sensing data were compared with landings (CPUE) between 1997 and 2007 and analyzed for partial influence obtained through the Generalized Additive Model. Additionally, significant variables were analyzed through Wavelet Cross-Spectrum, and periods of high correlation between variables in space and time were identified. The results indicated a high coherence between catch per unit effort (CPUE) and environmental variables on an interannual scale, suggesting that Red Snapper fishing is mainly influenced by the seasonal effects of oceanographic variables. These results suggest that fluctuations in Red Snapper catches between 1997 and 2007 may be the result of natural processes that occur in the Amazon Continental Shelf every year in synergy with environmental variables, which are also indirectly affected by the El Niño–Southern Oscillation (ENSO) pattern. 相似文献
386.
387.
388.
Truchado P Tourn E Gallez LM Moreno DA Ferreres F Tomás-Barberán FA 《Journal of agricultural and food chemistry》2010,58(24):12678-12685
To select and establish floral biomarkers of the botanical origin of Diplotaxis tenuifolia honeys, the flavonoids and glucosinolates present in bee-deposited nectar collected from hive combs (unripe honey) and mature honey from the same hives fron which the unripe honey samples were collected were analyzed by LC-UV-PAD-ESI-MS(n). Glycosidic conjugates of the flavonols quercetin, kaempferol, and isorhamnetin were detected and characterized in unripe honey. D. tenuifolia mature honeys contained the aglycones kaempferol, quercetin, and isorhamnetin. The differences between the phenolic profiles of mature honey and freshly deposited honey could be due to hydrolytic enzymatic activities. Aliphatic and indole glucososinolates were analyzed in unripe and mature honeys, this being the first report of the detection and characterization of glucosinolates as honey constituents. Moreover, these honey samples contained different amounts of propolis-derived flavonoid aglycones (1765-3171 μg/100 g) and hydroxycinnamic acid derivatives (29-1514 μg/100 g). Propolis flavonoids were already present in the freshly deposited nectar, showing that the incorporation of these compounds to honey occurs at the early steps of honey production. The flavonoids quercetin, kaempferol, and isorhamnetin and the glucosinolates detected in the samples could be used as complementary biomarkers for the determination of the floral origin of Argentinean Diplotaxis honeys. 相似文献
389.
Alarcón Marcelo Bustos Michelle Mendez Diego Fuentes Eduardo Palomo Ivan Lutz Mariane 《Plant foods for human nutrition (Dordrecht, Netherlands)》2020,75(2):215-222
Plant Foods for Human Nutrition - Cardiovascular disease (CVD) is the leading cause of death throughout the world. A major risk factor for CVD is platelet aggregation. Various plant extracts... 相似文献
390.