全文获取类型
收费全文 | 137篇 |
免费 | 13篇 |
专业分类
林业 | 9篇 |
农学 | 4篇 |
8篇 | |
综合类 | 5篇 |
农作物 | 11篇 |
水产渔业 | 7篇 |
畜牧兽医 | 96篇 |
园艺 | 1篇 |
植物保护 | 9篇 |
出版年
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 9篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 10篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 4篇 |
2013年 | 6篇 |
2012年 | 16篇 |
2011年 | 15篇 |
2010年 | 12篇 |
2009年 | 4篇 |
2008年 | 5篇 |
2007年 | 2篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1997年 | 1篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1978年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有150条查询结果,搜索用时 578 毫秒
101.
102.
Jochen Schöngart Florian Wittmann Angélica Faria de Resende Cyro Assahira Guilherme de Sousa Lobo Juliana Rocha Duarte Neves Maíra da Rocha Gisele Biem Mori Adriano Costa Quaresma Layon Oreste Demarchi Bianca Weiss Albuquerque Yuri Oliveira Feitosa Gilvan da Silva Costa Gildo Vieira Feitoza Flávia Machado Durgante Aline Lopes Susan E. Trumbore Thiago Sanna Freire Silva Hans ter Steege Adalberto Luis Val Wolfgang J. Junk Maria Teresa Fernandez Piedade 《水产资源保护:海洋与淡水生态系统》2021,31(12):1117-1135
- The Balbina hydropower dam in the Central Amazon basin, established in the Uatumã River in the 1980s, is emblematic for its socio-environmental disaster. Its environmental impacts go far beyond the reservoir and dam, however, affecting the floodplain forests (igapó) in the downstream area (dam shadow), which have been assessed using a transdisciplinary research approach, synthesized in this review.
- Floodplain tree species are adapted to a regular and predictable flood pulse, with high- and low-water periods occurring during the year. This was severely affected by the operation of the Balbina dam, which caused the suppression of both the aquatic phase at higher floodplain elevations and the terrestrial phase at lower floodplain elevations (termed the ‘sandwich effect’).
- During the period of construction and reservoir fill, large-scale mortality already occurred in the floodplains of the dam shadow as a result of reduced stream flow, in synergy with severe drought conditions induced by El Niño events, causing hydraulic failure and making floodplains vulnerable to wildfires.
- During the operational period of the dam, permanent flooding conditions at low topographical elevations resulted in massive tree mortality. So far, 12% of the igapó forests have died along a downstream river stretch of more than 125 km. As a result of flood suppression at the highest elevations, an encroachment of secondary tree species from upland (terra firme) forests occurred.
- More than 35 years after the implementation of the Balbina dam, the downstream impacts caused massive losses of macrohabitats, ecosystem services, and diversity of flood-adapted tree species, probably cascading down to the entire food web, which must be considered in conservation management.
- These findings are discussed critically, emphasizing the urgent need for the Brazilian environmental regulatory agencies to incorporate downstream impacts in the environmental assessments of several dam projects planned for the Amazon region.
103.
Weight records of Brazilian Nelore cattle, from birth to 630 d of age, recorded every 3 mo, were analyzed using random regression models. Independent variables were Legendre polynomials of age at recording. The model of analysis included contemporary groups as fixed effects and age of dam as a linear and quadratic covariable. Mean trends were modeled through a cubic regression on orthogonal polynomials of age. Up to four sets of random regression coefficients were fitted for animals' direct and maternal, additive genetic, and permanent environmental effects. Changes in measurement error variances with age were modeled through a variance function. Orders of polynomial fit from three to six were considered, resulting in up to 77 parameters to be estimated. Models fitting random regressions modeled the pattern of variances in the data adequately, with estimates similar to those from corresponding univariate analysis. Direct heritability estimates decreased after birth and tended to be lowest at ages at which maternal effect estimates tended to be highest. Maternal heritability estimates increased after birth to a peak around 110 to 120 d of age and decreased thereafter. Additive genetic direct correlation estimates between weights at standard ages (birth, weaning, yearling, and final weight) were moderate to high and maternal genetic and environmental correlations were consistently high. 相似文献
104.
A total of 20,065 weights recorded on 3016 Nelore animals were used to estimate covariance functions for growth from birth to 630 days of age, assuming a parametric correlation structure to model within-animal correlations. The model of analysis included fixed effects of contemporary groups and age of dam as quadratic covariable. Mean trends were taken into account by a cubic regression on orthogonal polynomials of animal age. Genetic effects of the animal and its dam and maternal permanent environmental effects were modelled by random regressions on Legendre polynomials of age at recording. Changes in direct permanent environmental effect variances were modelled by a polynomial variance function, together with a parametric correlation function to account for correlations between ages. Stationary and nonstationary models were used to model within-animal correlations between different ages. Residual variances were considered homogeneous or heterogeneous, with changes modelled by a step or polynomial function of age at recording. Based on Bayesian information criterion, a model with a cubic variance function combined with a nonstationary correlation function for permanent environmental effects, with 49 parameters to be estimated, fitted best. Modelling within-animal correlations through a parametric correlation structure can describe the variation pattern adequately. Moreover, the number of parameters to be estimated can be decreased substantially compared to a model fitting random regression on Legendre polynomial of age. 相似文献
105.
de Albuquerque Pedro Paulo Feitosa de Melo Renata Pimentel Bandeira de Farias Brito Marilene Bovino Fernanda de Souza Mariana Assunção Lima Anna Monteiro Correia de Oliveira Emerson Antônio Araújo de Moraes Pereira Helder Mota Rinaldo Aparecido 《Tropical animal health and production》2018,50(8):1929-1935
Tropical Animal Health and Production - Paratuberculosis is an incurable disease in ruminants with great worldwide economic impact, caused by Mycobacterium avium subsp. paratuberculosis (MAP). The... 相似文献
106.
Influence of outdoor rearing and oleic acid supplementation on lipid characteristics of muscle and adipose tissues from obese Alentejano pigs
下载免费PDF全文
![点击此处可从《Journal of animal physiology and animal nutrition》网站下载免费的PDF全文](/ch/ext_images/free.gif)
107.
Method for the estimation of genetic merit of animals with uncertain paternity under Bayesian inference
下载免费PDF全文
![点击此处可从《Zeitschrift für Tierzüchtung und Züchtungsbiologie》网站下载免费的PDF全文](/ch/ext_images/free.gif)
L. Shiotsuki F.F. Cardoso L.G. Albuquerque 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2018,135(2):116-123
The use of controlled mating or artificial insemination is impracticable in the case of large herds, mainly because of labour costs and the need to delimit areas during the breeding period. However, the exclusion of information from animals with uncertain paternity reduces genetic progress. The objectives of this study were as follows: (i) propose an iterative empirical Bayesian procedure to implement the hierarchical animal model (ITER); (ii) calculate the posterior probabilities of paternity by the maximum likelihood method following the concepts; (iii) compare an average numerator relationship matrix (ANRM), Bayesian hierarchical (HIER) models and ITER. Records of Nellore animals born between 1984 and 2006 from the zootechnical archive of Agropecuária Jacarezinho Ltda were used. For data consistency, records of contemporary groups (CGs) with fewer than three animals and animals whose records were 3.5 standard deviations above or below the mean of their CG were eliminated. After editing the data, 62,212 animals in the file and 12,876 animals in pedigree file were maintained, respectively. Spearman and Pearson correlations between the posterior mean of the genetic effects of animals were calculated to compare the ranking of animals for selection. Simulated data were used to confirm the veracity of the model. The correlations between ITER and HIER and between ITER and ANRM were similar evaluating different files, which decreased at the same proportion when only high‐ranked animals were evaluated. In conclusion, the model proposed herein is a suitable computational alternative to improve the prediction of breeding values of animals in genetic evaluations using large databases, including animals with uncertain paternity. 相似文献
108.
Tâmara Rebecca Albuquerque de Oliveira Hélio Wilson Lemos de Carvalho Moysés Nascimento Emiliano Fernandes Nassau Costa Antonio Teixeira do Amaral Junior Geraldo de Amaral Gravina José Luiz Sandes de Carvalho Filho 《Euphytica》2018,214(4):64
Adaptability and stability analysis methods that use a priori information allow identifying and selecting potentially productive genotypes with greater accuracy. The aim of the current study is to use the Eberhart and Russel’ Bayesian method as an instrument to analyze the adaptability and stability of hybrid maize cultivars and to assess the efficiency of using the distribution of informative and non-informative priors to select cultivars. Twenty-five (25) hybrid maize cultivars were assessed in 11 environments located in the Brazilian Northeastern region, during 2012 and 2013, according to a complete randomized block design, with two repetitions. The Eberhart and Russel’s methodology was performed in the GENES software, whereas the Bayesian procedure was implemented in the free software R, by using the MCMCregress function of the MCMCpack package. The adaptability and stability parameters values and the credibility intervals have shown that the Eberhart and Russel’s method via Bayesian technique has shown greater stability-estimation accuracy and greater efficiency in recommending cultivars adapted to favorable and unfavorable environments. The Bayesian methods using priories informative (M1) and few informative (M2) distributions have presented the same genotype classifications in the comparison between a priori distributions; however, according to the Bayes Factor, the M1 was the most adequate distribution to help finding more reliable estimates. 相似文献
109.
Comparison of two methods of seminal plasma removal on buffalo (Bubalus bubalis) sperm cryopreservation
下载免费PDF全文
![点击此处可从《Reproduction in domestic animals》网站下载免费的PDF全文](/ch/ext_images/free.gif)
RS Albuquerque R Morais AN Reis MS Miranda EAR Dias FM Monteiro CCP Paz M Nichi GKV Kawai CPF Della'Aqua FO Papa RB Viana LU Gimenes 《Reproduction in domestic animals》2017,52(5):905-910
Cryopreservation causes damage to spermatozoa, and methods minimizing this damage are therefore needed. Although much discussed, seminal plasma removal has become an alternative to improve sperm quality and viability after freezing and has been applied to different species in attempt to obtain good results. The objective of this study was to evaluate semen quality in buffaloes submitted to two methods for seminal plasma removal (filtration and centrifugation). Semen samples were collected from seven Murrah buffalo bulls (Bubalus bubalis) once a week for 8 weeks. Each ejaculate was divided into three groups: control (presence of seminal plasma), centrifugation and filtration. Sperm kinetics was evaluated with the computer‐assisted sperm analysis (CASA) system. Plasmalemma and acrosomal membrane integrity, mitochondrial membrane potential and reactive oxygen species (ROS) were measured by flow cytometry, and lipid peroxidation was evaluated by the thiobarbituric acid reactive substances (TBARS) assay. Seminal plasma removal did not improve sperm kinetics compared to the control group. Centrifugation increased the number of cells with damaged acrosomal membranes (0.77 ± 0.05) and filtration caused greater plasmalemma and acrosomal membrane damage (22.18 ± 1.07). No difference in the mitochondrial membrane potential was observed between groups. In contrast, ROS production was higher in the centrifugation group compared to the control and filtration groups, although no differences in TBARS formation were detected. In conclusion, seminal plasma removal did not improve the quality of thawed buffalo semen compared to control in terms of sperm kinetics, membrane integrity, mitochondrial membrane potential or lipid peroxidation. 相似文献
110.
Flavia Rita Ferreira Francisco Ribeiro de Araujo Neto Henrique Barbosa Borges Rusbel Raul Aspilcueta‐Borquis Naudim Alejandro Hurtado‐Lugo Henrique Nunes de Oliveira Lucia Galvão de Albuquerque Humberto Tonhati 《Animal Science Journal》2017,88(8):1212-1219
This article reports genetic analysis of the weight at different ages of Murrah water buffaloes, using random regression models (RRM). Models ranging from third to sixth order polynomial were used to describe direct genetic and animal permanent environmental effects. Contemporary group was included as a fixed effect, and a cubic polynomial was used to model the mean curve of the population. The residual was modeled considering a log‐linear function. Two models were selected for study of genetic parameters. The first model included third and sixth order polynomials for direct genetic and animal permanent environmental effects (M36). The second model included sixth order polynomials for all random effects (M66). The estimates of heritability varied from 0.16 + 0.04 (44 days) to 0.38 + 0.04 (568 days) for model M36 and from 0.16 + 0.05 (33 days) to 0.42 + 0.05 (600 days) for model M66. Regarding estimates of the correlation for all effects, the magnitude tended to decline with the increase of the time span between measurements. These results indicate that the species has potential for genetic selection based on weight at different ages, since we found favorable genetic variability within the herd, with selection likely to be more efficient at ages near 600 days. 相似文献