全文获取类型
收费全文 | 179篇 |
免费 | 15篇 |
专业分类
林业 | 17篇 |
农学 | 13篇 |
24篇 | |
综合类 | 5篇 |
农作物 | 10篇 |
水产渔业 | 31篇 |
畜牧兽医 | 64篇 |
园艺 | 5篇 |
植物保护 | 25篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 9篇 |
2020年 | 15篇 |
2019年 | 16篇 |
2018年 | 13篇 |
2017年 | 9篇 |
2016年 | 11篇 |
2015年 | 3篇 |
2014年 | 14篇 |
2013年 | 10篇 |
2012年 | 10篇 |
2011年 | 8篇 |
2010年 | 8篇 |
2009年 | 15篇 |
2008年 | 8篇 |
2007年 | 8篇 |
2006年 | 2篇 |
2005年 | 5篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 1篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有194条查询结果,搜索用时 46 毫秒
51.
The Supracloacal Chromolipoid Body of the Black Vulture (Coragyps atratus): Anatomical, Histological and Histochemical Considerations
下载免费PDF全文
![点击此处可从《Canadian journal of veterinary research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
W. M. Corrêa G. H. Silva L. T. Kawabe A. C. Carneiro 《Canadian journal of veterinary research》1969,33(2):160-163
During histological and physiological investigations of black vultures (Coragyps atratus) dissection revealed the presence of an “organ”, the supracloacal chromolipoid body, which has no counterpart among other warm blooded animals.
The organ occurs in both sexes and in birds of different ages. It is located in the median sagittal plane dorsal to the cloaca. It is enveloped by a smooth muscle-connective tissue capsule and has a rich blood supply.
The supracloacal body is yellow-brown in color being composed chiefly of islands of pigment cells.
Histochemically, the pigment is a chromolipoid as defined by Ciaccio.
相似文献52.
C Feltrin CA Cooper N Mohamad‐Fauzi VHV Rodrigues LH Aguiar S Gaudencio‐Neto LT Martins CEM Calderón AS Morais IS Carneiro TM Almeida ING Silva JL Rodrigues EA Maga JD Murray AB Libório LR Bertolini M Bertolini 《Reproduction in domestic animals》2014,49(4):648-656
The presence of the zona pellucida has been perceived as a requirement for the oviductal transfer of cloned embryos at early stages of development while protecting the embryo from an immune system response. We hypothesized that steroid hormone therapy could reduce a potential cellular immune response after the transfer of zona‐free cloned embryos into the oviduct of recipient female goats. In Experiment 1, seven does were used to study the systemic immunosuppressant effect of the methylprednisolone administration (for 3 days) on blood cell counts. Whole blood was collected prior to treatment with methyprednisolone and then on Days 1, 2, 3, 4, 7, 14, 21 and 28 after the first dose of methylprednisolone for the analysis of haematological parameters. Methylprednisolone treatment significantly reduced circulating white blood cells and neutrophils in comparison with pre‐treatment levels, demonstrating a systemic immunosuppressant effect. In Experiment 2, a group of 58 does were used as recipient females to study the effect of administration of methylprednisolone for 3 days on the establishment of pregnancies after the transfer of zona‐free cloned embryos into the oviducts. No effects on pregnancy rates on Day 30 were observed regarding the distinct treatment groups (control vs. methylprednisolone), the source of oocytes (in vivo‐ vs in vitro‐matured) or the presence or absence of the zona pellucida in embryos. In summary, methylprednisolone was effective at inducing a systemic immunosuppressed state in goats, but the treatment prior to embryo transfer did not affect pregnancy rates. Moreover, pregnancy rates were similar between zona‐free and zona‐intact goat cloned embryos. 相似文献
53.
Câmara G Dutra Aguiar AP Escada MI Amaral S Carneiro T Vieira Monteiro AM Araújo R Vieira I Becker B 《Science (New York, N.Y.)》2005,307(5712):1043-4; author reply 1043-4
54.
Maria Filomena Carneiro 《Euphytica》1997,96(1):167-172
The most important advances obtained on in vitro coffee regeneration systems and in coffee genetic transformation, drawing
perspectives and scopes to further studies in these fields are presented and discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
55.
Paulo Marcelo Paiva Marcelino Carneiro Guedes Claudia Funi 《Forest Ecology and Management》2011,261(3):508-514
The regeneration of Brazil nut trees depends on tree-fall gaps in the forest. However, shifting cultivation fallows also create comparable biotic and abiotic opportunities for the dispersion and establishment of this gap-loving species. At the same time, the ability of Brazil nut trees to resprout enables fallow individuals to survive successive slash-and-burn cycles. Recognizing the importance of shifting cultivation for the food security of forest dwellers, we investigated whether the high level of Brazil nut regeneration found in cultivation fallows could be explained by the resprouting capability of Brazil nut trees, the number of cultivation cycles, past agricultural use and distance to the nearest conspecific productive adults. We found that the Brazil nut tree population density increased from 8.86 trees ha−1 to 13.69 trees ha−1 and 27.09 trees ha−1 at sites after one, two and three or more shifting cultivation cycles, respectively. As a consequence of resprouting, after a certain number of shifting cultivation cycles, the fallows become dominated by Brazil nut trees, and the landholders may decide to preserve them and to exclude enriched sites from future agricultural use. Protected for their extractive value, the secondary forests spontaneously enriched with Brazil nut trees are allowed to develop into nut-producing forests that have reduced chances of conversion into crops or pastures, thus reversing the classical process of Amazon forest degradation. 相似文献
56.
Paiva SR Facó O Faria DA Lacerda T Barretto GB Carneiro PL Lobo RN McManus C 《Tropical animal health and production》2011,43(7):1449-1457
The first registers of Somali sheep in Brazil are from the beginning of the 1900s. This breed, adapted to the dry climate
and scarce food supply, is restricted in the northeast region of the country. Molecular marker technologies, especially those
based on genotyping microsatellite and mtDNA loci, can be used in conjunction with breeding (pedigree analysis) and consequently
the maintenance of genetic variation in herds. Animals from the Brazilian Somali Conservation Nuclei from Embrapa Sheep and
Goats in Ceará State were used to validate genetic monitoring by traditional pedigree methods and molecular markers. Nineteen
microsatellite markers and 404 base pairs from the control region of mtDNA were used. For total herd diversity, an average
5.32 alleles were found, with expected heterozygosity of 0.5896, observed heterozygosity of 0.6451, 0.4126 for molecular coancestrality,
and coefficient of inbreeding (F
IS) was −0.095. Comparing molecular coancestrality means over the years, there was a consistent increase in this parameter within
the herd, increasing from 0.4157 to 0.4769 in 2 years (approx. 12% variation). Sixteen mtDNA haplotypes were identified. Inbreeding
and other estimates from genealogical analyses confirm the results from molecular markers. From these results, it is possible
to state that microsatellites are useful tools in genetic management of herds, especially when routine herd recording is not
carried out, or there were gaps in recent generations. As well as pedigree control, genetic diversity can be optimized. Based
on the results, and despite herd recording in the herd of Brazilian Somali of Embrapa Sheep and Goats, additional management
measures need to be carried out in this herd to reduce inbreeding and optimize genetic variation. 相似文献
57.
de Souza Carneiro Adriana dos Santos Adriano Laviola Bruno Galvas Teodoro Larissa Pereira Ribeiro Teodoro Paulo Eduardo Rodrigues Erina Vitrio 《Genetic Resources and Crop Evolution》2022,69(1):245-254
Genetic Resources and Crop Evolution - Jatropha (Jatropha curcas L.) is an oleaginous potential, howetever, some studies report that there is low genetic diversity in Brazilian genotypes.... 相似文献
58.
da Silva Carneiro Lázaro Ribeiro Milton Cezar Aguiar Willian Moura de de Fátima Priante Camila Frantine-Silva Wilson Gaglianone Maria Cristina 《Landscape Ecology》2022,37(6):1587-1601
Landscape Ecology - Multiscale approaches are essential for understanding ecological processes and detecting the scale of effect. However, nested multiscale approaches retain the effect of the... 相似文献
59.
Vanessa S. Mattos Raycenne R. Leite Marcilene F.A. Santos Cesar B. Gomes Philippe Castagnone-Sereno Juvenil E. Cares Regina M.D.G. Carneiro 《Plant pathology》2021,70(9):2217-2228
Recently a Meloidogyne species complex was detected parasitizing and causing damage to irrigated rice in southern Brazil, highlighting the need to study the genetic diversity of these species and their pathogenicity to Oryza spp. in order to select genotypes of rice with multiple resistance. This study compared the genetic diversity of Brazilian Meloidogyne spp. isolates from irrigated rice and evaluated the reaction of four wild accessions of Oryza species (O. glumaepatula, O. longistaminata, O. grandiglumis, and O. alta) and two cultivated species, O. glaberrima and O. sativa (control) to M. ottersoni, M. oryzae, and two variants of M. graminicola (Est G2 and Est G3). Genetic variability was assessed using RAPD and AFLP markers. M. graminicola and M. ottersoni showed high intraspecific variability: 83.76% and 41.14%, respectively. Cluster analysis showed a clear separation among rice root-knot nematodes (RKNs) into subclades according to their esterase phenotypes with 100% bootstrap. For rice resistance screening, plants were inoculated with 5,000 eggs, and the nematode reproduction factor evaluated 90–120 days postinoculation. O. glumaepatula, an American wild species, was highly resistant or resistant to all rice RKNs tested and is a valuable source of multiple resistance. Overall, the other rice species also showed different levels of resistance. Conversely, O. longistaminata exhibited low levels of resistance. M. graminicola Est G3 was the most aggressive isolate. Sources of resistance against RKN in wild Oryza genotypes, especially in an AA genome like O. glumaepatula, may be of great interest for future breeding programmes in cultivated rice. 相似文献
60.
Development and agronomic performance of common bean lines simultaneously resistant to anthracnose, angular leaf spot and rust 总被引:1,自引:0,他引:1
V. A. Ragagnin T. L. P. O. de Souza D. A. Sanglard K. M. A. Arruda M. R. Costa A. L. Alzate-Marin J. E. de S. Carneiro M. A. Moreira E. G. de Barros 《Plant Breeding》2009,128(2):156-163
The common bean is affected by several pathogens that can cause severe yield losses. Here we report the introgression of resistance genes to anthracnose, angular leaf spot and rust in the 'carioca-type' bean cultivar 'Rudá'. Initially, four backcross (BC) lines were obtained using 'TO', 'AB 136', 'Ouro Negro' and 'AND 277' as donor parents. Molecular fingerprinting was used to select the lines genetically closer to the recurrent parent. The relative genetic distances between 'Rudá' and the BC lines varied between 0.0% and 1.99%. The BC lines were intercrossed and molecular markers linked to the resistance genes were used to identify the plants containing the genes of interest. These plants were selfed to obtain the F2 , F3 and F4 plants which were selected based on the presence of the molecular markers mentioned and resistance was confirmed in the F4 generation by inoculation. Four F4:7 pyramid lines with all the resistance genes showed resistance spectra equivalent to those of their respective donor parents. Yield tests showed that these lines are as productive as the best 'carioca-type' cultivars. 相似文献