全文获取类型
收费全文 | 266篇 |
免费 | 12篇 |
专业分类
林业 | 20篇 |
农学 | 9篇 |
51篇 | |
综合类 | 6篇 |
农作物 | 24篇 |
水产渔业 | 23篇 |
畜牧兽医 | 117篇 |
园艺 | 10篇 |
植物保护 | 18篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 18篇 |
2020年 | 13篇 |
2019年 | 13篇 |
2018年 | 17篇 |
2017年 | 15篇 |
2016年 | 14篇 |
2015年 | 12篇 |
2014年 | 18篇 |
2013年 | 13篇 |
2012年 | 25篇 |
2011年 | 23篇 |
2010年 | 9篇 |
2009年 | 12篇 |
2008年 | 7篇 |
2007年 | 19篇 |
2006年 | 6篇 |
2005年 | 9篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1980年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有278条查询结果,搜索用时 15 毫秒
141.
Effects of light intensity on growth,feeding activity and development in common sole (Solea solea L.) larvae in relation to sensory organ ontogeny 下载免费PDF全文
Erika Bonvini Luca Parma Pier Paolo Gatta Luciana Mandrioli Rubina Sirri Giovanna Martelli Eleonora Nannoni Attilio Mordenti Alessio Bonaldo 《Aquaculture Research》2016,47(6):1809-1819
The effects of four light intensities (1000 lx, 500 lx, 50 lx, 3 lx) on growth, survival and feeding activity in common sole (Solea solea L.) larvae were studied from 4 to 51 days post hatching (dph). During the pelagic larval stage (4–12 dph), larvae reared at 3 lx showed a lower growth. From 19 onwards, the larvae reared under 3 lx displayed a significant (P ≤ 0.05) higher SGR than the other treatments and a higher final weight compared to 1000 lx and 500 lx. Survival rate was higher under intermediate light intensities (500 and 50 lx). Larvae reared at 3 lx displayed a significant delay in the degree of metamorphosis compared to the other treatments, while at 33 dph metamorphosis was completed under all treatments. Histological examination revealed the importance of vision and light in the first feeding of this species, while after metamorphosis, the full development of other sensory organs indicated that feeding activity is also mediated by chemosensory perception. Results indicate that high light intensity seems to be more suitable during the pelagic larvae, while the opposite would ensure better growth from the onset of metamorphosis to the benthic phase. 相似文献
142.
Pansa Marco G. Blandino Massimo Ingegno Barbara L. Ferrari Ester Reyneri Amedeo Tavella Luciana 《Journal of pest science》2015,88(1):201-208
Journal of Pest Science - Sunn pests are responsible for serious kernel damage on wheat (Triticum aestivum L., Poaceae), affecting bread-making quality from their feeding at the late milk-ripe... 相似文献
143.
Luciana Grange 《Soil biology & biochemistry》2004,36(9):1389-1398
Although rhizobia for common bean (Phaseolus vulgaris L.) are established in most Brazilian soils, understanding of their genetic diversity is very poor. This study characterized bean strains from two contrasting ecosystems in Brazil, the Northeast Region, with a semi-arid climate and neutral soils and the South Region, with a humid subtropical climate and acid soils. Seedlings of the cultivars Negro Argel and Aporé were used to trap 243 rhizobial isolates from 12 out of 14 sites. An analysis of ERIC-PCR products revealed enormous variability, with 81% of the isolates representing unique strains considering a level of 70% of similarity. In general, there was no effect of either the bean cultivar, or the ecosystem on rhizobial diversity. One-hundred and one strains showing genetic relatedness (ERIC-PCR) less than 70% were further analyzed using restriction fragment length polymorphism (RFLP) of the 16 S rDNA cleaved with five restriction enzymes. Twenty-five different profile combinations were obtained. Rhizobium etli was the predominant species, with 73 strains showing similar RFLP profiles, while 12 other strains differed only by the profile with one restriction enzyme. Fifty strains were submitted to sequencing of a 16 S rDNA fragment, and 34 clustered with R. etli, including strains with RFLP-PCR profiles similar to those species or differing by one restriction enzyme. However, other strains differing by one or two enzymes were genetically distant from R. etli and two strains with identical profiles showed higher similarity to Sinorhizobium fredii. Other strains showed higher similarity of bases with R. tropici, R. leguminosarum and Mesorhizobium plurifarium, but some strains were quite dissimilar and may represent new species. Great variability was also verified among the sequenced strains in relation to the ability to grow in YMA at 40 °C, in LB, to synthesize melanin in vitro, as well as in symbiotic performance, including differences in relation to the described species, e.g. many R. etli strains were able to grow in LB and in YMA at 40 °C, and not all R. tropici were able to nodulate Leucaena. 相似文献
144.
Luciana Lasry Benchimol Tatiana de Campos Sérgio Augusto Morais Carbonell Carlos Augusto Colombo Alisson Fernando Chioratto Eduardo Fernandes Formighieri Lígia Regina Lima Gouvêa Anete Pereira de Souza 《Genetic Resources and Crop Evolution》2007,54(8):1747-1762
A common bean genomic library was constructed using the ‘IAC-UNA’ variety enriched for (CT) and (GT) for microsatellite motifs. From 1,209 sequenced clones, 714 showed microsatellites distributed over 471 simple and 243 compound motifs. GA/CT and GT/CA were the most frequent motifs found among these sequences. A total of 123 microsatellites has been characterized. Out of these, 87 were polymorphic (73.7%), 33 monomorphic (26.8%), and 3 (2.4%) did not amplify at all. In a sample of 20 common bean materials selected from the Agronomic Institute Germplasm Bank, the number of alleles per locus varied 2–9, with an average of 2.82. The polymorphic information content (PIC) of each marker varied from 0.05 to 0.83, with a 0.45 average value. Cluster and principal coordinate analysis of the microsatellite data were consistent with the original assignment of the germplasm accessions into the Andean and Mesoamerican gene pools of common bean. Low polymorphism levels detected could be associated with the domestication process. These microsatellites could be a valuable resource for the bean community because of their use as new markers for genetic studies. 相似文献
145.
Phytotoxicity of Flumequine (F) on the aquatic duckweed, Lemna minor L., and plant drug uptake were evaluated by a simple ecotoxicological test. Flumequine, at all concentrations between 50 and 1000 μg L-1 tested, affected the plant growth: leaves and roots were damaged, but duckweed continued to grow on a five weeks period. Furthermore, increasing drug concentrations decreased the chlorophyll b content in plants. These effects depend on F uptake by plants, which is quite high (from 0.72 to 13.93 μg g-1 plant dry weight). Based on this activity, Lemna can be taken into consideration as a tool for in situ remediation of drug contaminated waters: the presence of Lemna significantly lower the F concentration in culture media on a five weeks period. Results strongly support its remediation capability. 相似文献
146.
Ana Clara N. P. C. S. Viana Jeferson L. S. Freitas Lívia C. Magalhães Lívia B. Campos Alexandre R. Silva Moacir F. Oliveira Vicente J. F. Freitas Luciana M. Melo 《Reproduction in domestic animals》2021,56(2):351-359
Ovarian response of collared peccaries (Pecari tajacu), after hormonal stimulation with gonadotropin association (eCG/hCG), was accessed by both gene expression and follicular development. Thus, collared peccaries (n = 8) were treated with the dose used for sows (swine dose, SWD) or with dose adjusted for peccary's weight (allometric dose, ALD). The gene expression of receptors was evaluated for both gonadotropins (FSHR and LHCGR) and growth factors (proteins codified by TGFβR-1, BMPR1-A and BMPR2 genes) in antral follicles, cortex and corpora haemorrhagica (CH). Five days after gonadotropin injection, all females presented CH. The ovulation rate was similar (p > .05) between SWD (4.00 ± 1.17) and ALD (2.50 ± 0.43) group. The total number of follicles per animal and amounts of small (<3 mm), medium (3–5 mm) and large (>5 mm) follicles was similar among groups. However, SWD produced large follicles heavier than ALD group, as accessed by weight of follicular wall biopsies. Ovarian follicles expressed both gonadotropin and growth factor receptors at levels which are independent from gonadotropin dose. In conclusion, the two gonadotropin doses (SWD and ALD) can be used for ovarian stimulation of collared peccary. Additionally, FSH and growth factors (TGFβR-1, BMPR1-A and BMPR2) receptors are more expressed in the early follicle development, while LH receptor seems to be more important in the final of follicular growth. 相似文献
147.
Herlon M. Alhadas Sebastião C. Valadares Filho Luis O. Tedeschi Rizielly S. R. Vilela Gilyard A. P. Souza Bruno C. Lage Breno C. Silva Luciana N. Rennó Mario F. Paulino 《Animal Science Journal》2021,92(1):e13623
This study evaluated the effect of including low-fat dried distillers grains (DDG) on young Nellore bulls performance, nutritional parameters, and nitrogen metabolism. Thirty-five Nellore cattle were randomly divided into four diets: without dried distillers grains (D0) or with the inclusion of DDG at 150 g/kg (D150), 300 g/kg (D300), or 450 g/kg (D450). The evaluation period lasted 126 days, and three periods of collection of feces and urine were carried out. Final body weight (P = 0.099) and average daily gain (P = 0.097) tended to decrease linearly; the digestibility of dry matter (P < 0.001), organic matter (P < 0.001), ether extract (P < 0.001) and nonfiber carbohydrates (P < 0.001), and intakes of total digestible nutrients (TDN, P < 0.001) decreased linearly. The increase in crude protein intake (P < 0.001) did not result in an increase in the amount of nitrogen retained (P = 0.540). We concluded that the inclusion of low-fat DDG in finishing diets up to the level of 450 g/kg tends to reduce animal performance and the intake of TDN. 相似文献
148.
Gomes da Silva Aline Paulino Mário Fonseca da Silva Amorim Lincoln Detmann Edenio Rennó Luciana Navajas de Souza Duarte Márcio Henrique de Moura Felipe Prímola de Melo Luciano Henrique Silva e Paiva Paulo Manso Marcos Rocha Valério de Carvalho Victor 《Tropical animal health and production》2017,49(2):383-387
Tropical Animal Health and Production - Creep feeding has been used to reduce calves’ nutritional dependence on the cow, but research results under tropical conditions have not been... 相似文献
149.
Survey of the Bru1 gene for brown rust resistance in Brazilian local and basic sugarcane germplasm 下载免费PDF全文
Ana Caroline Neuber Fernanda Raquel Camilo dos Santos Juliana Borges da Costa Maicon Volpin Mauro Alexandre Xavier Dilermando Perecin Roberto Carlos Villavicencio Burbano Marcos Guimarães de Andrade Landell Luciana Rossini Pinto 《Plant Breeding》2017,136(2):182-187
Bru1 is currently the major gene conferring brown rust resistance in sugarcane, and diagnostic markers are available. A survey for the presence of this gene was conducted on 391 genotypes including Brazilian cultivars, clones and basic germplasm. The efficiency of these markers for identifying resistant cultivars and artificially inoculated basic germplasm was also evaluated. The Bru1 frequency among cultivars (73.5%) suggests this gene is the prevalent source of brown rust resistance in Brazilian sugarcane breeding programmes. Most of the cultivars known to be resistant were positive for Bru1, although other genes for resistance could be present in lines not having Bru1. Only 17.8% of the basic germplasm accessions were positive for the Bru1 gene, and a low correlation between Bru1 diagnostic markers and brown rust severity was observed for basic germplasm accessions. Overall, Bru1 diagnostic markers proved to be efficient identifying resistant cultivars and clones and have potential to be in screening brown rust resistance in Brazilian breeding programmes. 相似文献
150.
Marcelo?C.?de?AlvesEmail author Fábio?M.?da?Silva Jair?Campos?Moraes Edson?A.?Pozza Marcelo?S.?de?Oliveira Júlio?C.?S.?Souza Luciana?S.?Alves 《Precision Agriculture》2011,12(1):18-31
The advent of geostatistics and geographical information systems has made it possible to analyze complex spatial patterns
of ecological phenomena over large areas in applied insect ecology and pest management. The objective of this study was to
use geostatistics to characterize the spatial structure and map the spatial variation of damage caused by the berry borer
(Hypothenemus hampei) and leaf miner (Leucoptera coffeella) in a coffee agroecosystem planted with the cultivar Catuai Vermelho IAC-99. Infestations of berry borer and leaf miner were
evaluated in fruits and leaves, respectively. The pests were monitored at 67 georeferenced points in an area of 6.6 ha in
2005, 2006 and 2007. Variograms estimated by the method of moments (MoM) and residual maximum likelihood REML were compared.
The latter were generally better in terms of the kriging error coefficients. Spherical variograms estimated by REML for berry
borer infestation in fruits had ranges of spatial dependence of 34.62–118.4 m and for the leaf miner they were 53.93–133.7 m.
For models fitted by weighted ordinary least squares (OLS) to the MoM experimental variogram, the ranges varied between 37.22
and 68.67 m for the berry borer and 100 and 155.4 m for leaf miner infestation. The variogram model parameters were used with
the data for ordinary kriging to map the spatial variation of coffee pests for different monitoring periods. If there was
no suitable variogram, inverse distance weighting was used to map the variation. The maps enabled visualization of the intensity
of infestation of the insect pests for the different periods evaluated. 相似文献