全文获取类型
收费全文 | 707篇 |
免费 | 58篇 |
专业分类
林业 | 63篇 |
农学 | 32篇 |
基础科学 | 2篇 |
153篇 | |
综合类 | 27篇 |
农作物 | 52篇 |
水产渔业 | 53篇 |
畜牧兽医 | 327篇 |
园艺 | 6篇 |
植物保护 | 50篇 |
出版年
2023年 | 4篇 |
2022年 | 16篇 |
2021年 | 41篇 |
2020年 | 41篇 |
2019年 | 46篇 |
2018年 | 35篇 |
2017年 | 32篇 |
2016年 | 38篇 |
2015年 | 27篇 |
2014年 | 27篇 |
2013年 | 46篇 |
2012年 | 59篇 |
2011年 | 68篇 |
2010年 | 33篇 |
2009年 | 36篇 |
2008年 | 38篇 |
2007年 | 31篇 |
2006年 | 24篇 |
2005年 | 36篇 |
2004年 | 16篇 |
2003年 | 32篇 |
2002年 | 11篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有765条查询结果,搜索用时 15 毫秒
131.
Cláudio Eduardo Silva Freitas Eduardo Robson Duarte Dorismar David Alves Isabel Martinele Marta D’Agosto Franciane Cedrola Angélica Alves de Moura Freitas Franklin Delano dos Santos Soares Makenzi Beltran 《Tropical animal health and production》2017,49(4):807-812
A ciliate protozoa suppression can reduce methane production increasing the energy efficiency utilization by ruminants. The physicochemical characteristics of rumen fluid and the profile of the rumen protozoa populations were evaluated for sheep fed banana leaf hay in replacement of the Cynodon dactylon cv. vaqueiro hay. A total of 30 male sheep were raised in intensive system during 15 days of adaptation and 63 days of experimental period. The animals were distributed in a completely randomized design that included six replicates of five treatments with replacement levels (0, 25, 50, 75, and 100%) of the grass vaquero for the banana leaf hay. Samples of fluid were collected directly from the rumen with sterile catheters. Color, odor, viscosity, and the methylene blue reduction potential (MBRP) were evaluated and pH estimated using a digital potentiometer. After decimal dilutions, counts of genus protozoa were performed in Sedgewick Rafter chambers. The averages of pH, MBRP, color, odor, and viscosity were not influenced by the inclusion of the banana leaf hay. However, the total number of protozoa and Entodinium spp. population significantly decreased at 75 and 100% inclusions of banana leaf hay as roughage. 相似文献
132.
133.
Virulence-associated trimeric autotransporters of Haemophilus parasuis are antigenic proteins expressed in vivo 总被引:1,自引:0,他引:1
Alex Olvera Sonia Pina Marta P��rez-Sim�� Simone Oliveira Albert Bensaid 《Veterinary research》2010,41(3)
Glässer’s disease is a re-emerging swine disease characterized by a severe septicaemia. Vaccination has been widely used to control the disease, although there is a lack of extended cross-protection. Trimeric autotransporters, a family of surface exposed proteins implicated in host-pathogen interactions, are good vaccine candidates. Members of this family have been described in Haemophilus parasuis and designated as virulence-associated trimeric autotransporters (VtaA). In this work, we produced 15 recombinant VtaA passenger domains and looked for the presence of antibodies directed against them in immune sera by immunoblotting. After infection with a subclinical dose of H. parasuis Nagasaki, an IgG mediated antibody response against 6 (VtaA1, 5, 6, 8, 9 and 10) of the 13 VtaA of the Nagasaki strain was detected, indicating that they are expressed in vivo. IgA production against VtaA was detected in only one animal. VtaA were more likely to be late antigens when compared to early (Omp P5 and Omp P6) and late (YaeT) defined antigens. Antibody cross-reaction with two orthologs of Nagasaki’s VtaA5 and 6, VtaA15 and 16 of strain HP1319, was also detected. No antibodies against VtaA were detected in the sera of animals immunized with a bacterin of the Nagasaki strain, suggesting poor expression in the in vitro conditions used. Taken together, these results indicate that VtaA are good candidate immunogens that could be used to improve H. parasuis vaccines. However, their capacity to confer protective immunity needs to be further studied. 相似文献
134.
Marta Lizandra do Reo Leal Emmanuel Veiga de Camargo Daniel Henrique Ross Marcelo Beltrão Molento Sonia Terezinha dos Anjos Lopes João Batista Teixeira da Rocha 《Veterinary research communications》2010,34(6):549-555
The objective of this study was to evaluate oxidative stress in lambs experimentally infected with Haemonchus contortus and supplemented with selenium and vitamin E. Twenty male Corriedale lambs were divided into four experimental groups with
five animals each: G1 consisted of animals infected and supplemented with 0.2 mg/kg of live weight (LW) sodium selenite by
intramuscular injection (IM); G2 consisted of animals infected with larvae and supplemented with 0.2 mg/kg LW sodium selenite
IM and 2000 IU per animal of Vitamin E IM; G3 consisted of animals infected with larvae and supplemented with 2000 IU per
animal of Vitamin E IM; and G4 consisted of animals infected with larvae. The animals were infected orally with 500 H. contortus larvae (L3) every 48 hours for 20 days. For biochemical analyses and eggs per grams of feces (EPG) evaluation, blood and
feces were both collected at zero (T0), 20 (T1), 40 (T2) and 60 (T3) days. The weight of the animals was also measured at
these times. Lower TBARS values were observed in the supplemented animals compared to the control group. The groups supplemented
with Selenium exhibited blood GSH-Px activity higher than that of non-supplemented animals. Supplementation with selenium
provided greater antioxidant protection against oxidative stress generated from experimental infection of lambs with H. contortus. 相似文献
135.
136.
Studies on the effect of forest loss and fragmentation on plant species richness at different spatial scales have yielded contradictory results that have been attributed to different ways to measure fragmentation. The main goal of this study was to investigate the independent and combined effects of forest loss and habitat fragmentation on woody species richness. Woody species were grouped according to their habitat requirements (forest specialists, forest generalists, non-forest and total woody species). We used regression models to investigate the effect of fragmentation and human occupation on woody species richness. The underlying factors were investigated by partitioning of the variation, i.e. decomposing the variation in species richness between the pure effects of forest loss, fragmentation and human occupation. The relationship between species richness and forest loss resulted extremely non-linear. The models for forest specialist, generalist and total woody species richness accounted for 35%, 31% and 33% of the total variance respectively. Model for non-forest species richness only accounted for 7% of the total variance. The largest fraction of variability in species richness was accounted by fragmentation variables for all groups (except for non-forest species). Results emphasize the larger independent effect of fragmentation over forest loss, suggesting that species variation is mainly conditioned by the spatial configuration of the habitat. 相似文献
137.
138.
Thibaut Olivier Vaidevutis Šveikauskas Elisabeth Demonty Kris De Jonghe Pascal Gentit Mojca Viršček-Marn Sabine Grausgruber-Gröger Sébastien Morio Francesco Faggioli Michèle Visage Frédéric Fauche Maria Gusina Marta Luigi Helena Lasner Irena Mavrič-Pleško 《European journal of plant pathology / European Foundation for Plant Pathology》2016,144(3):645-654
139.
Feasibility of using rare earth elements (REEs) to mark and identify escaped farmed Atlantic salmon Salmo salar L.
下载免费PDF全文
![点击此处可从《Aquaculture Research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Marta Pérez de Nanclares Jens‐Erik Dessen Kjell‐Arne Rørvik Yngvar Thomassen Magny S Thomassen 《Aquaculture Research》2016,47(6):1885-1898
A series of rare earth elements (REEs) were evaluated as potential markers in scales of Atlantic salmon 1+ and 0+ smolt by addition of these elements to the feed. Chlorides of 5 REEs were tested, alone or in combination: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd) and dysprosium (Dy). The labelled‐diets contained 125 or 250 mg REE kg?1 feed and were administered for up to 10 weeks. Fish scales were collected and analysed by inductively coupled plasma‐mass spectrometry (ICP‐MS) before start, 5 and 10 weeks after labelling started and finally 2 or 4 months after marking. The results demonstrated that the five tested elements were clearly incorporated into the scales of the fish fed the supplemented diets. Uptake and concentrations increased gradually during the feeding period, and no principal differences were found between the two smolt types. Combining 2 REEs in the same feed did not affect the incorporation of either of them. After a ‘dilution’‐period of 2–4 months the concentrations of all markers (except La) in the scales of the treated‐fish were still significantly higher than those of the untreated‐fish. The background concentrations of the tested markers and some other elements were also measured and found to give interesting information. 相似文献
140.