全文获取类型
收费全文 | 81篇 |
免费 | 6篇 |
专业分类
林业 | 6篇 |
农学 | 2篇 |
基础科学 | 3篇 |
12篇 | |
综合类 | 2篇 |
农作物 | 1篇 |
水产渔业 | 3篇 |
畜牧兽医 | 49篇 |
园艺 | 6篇 |
植物保护 | 3篇 |
出版年
2021年 | 6篇 |
2020年 | 7篇 |
2019年 | 4篇 |
2017年 | 6篇 |
2016年 | 1篇 |
2015年 | 4篇 |
2014年 | 3篇 |
2013年 | 1篇 |
2012年 | 7篇 |
2011年 | 8篇 |
2010年 | 1篇 |
2009年 | 5篇 |
2008年 | 4篇 |
2007年 | 4篇 |
2006年 | 7篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2002年 | 1篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
排序方式: 共有87条查询结果,搜索用时 31 毫秒
1.
Lasmar Chaim J. Queiroz Antônio C. M. Rosa Clarissa Carvalho Nathália S. Schmidt Fernando A. Solar Ricardo R. C. Paolucci Lucas N. Cuissi Rafael G. Ribas Carla R. 《Landscape Ecology》2021,36(9):2583-2597
Landscape Ecology - Harmful effects of habitat loss and fragmentation can be detected across multiple spatial scales, yet most studies that aim to characterize these effects take place at a single... 相似文献
2.
3.
Marcelo Luiz Laia Acelino Couto Alfenas Sergio Hermnio Brommonschenkel Shinitiro Oda Eduardo Jose de Melo Inae Marie de Arau jo Silva Janana Fernandes Goncalves Ariadne Marques 《林业研究》2015,(3)
Disease-resistant genes play an important role in defending against a variety of pathogens and insect pests in plants. Most of the disease-resistant genes encode pro-teins with conserved leucine rich r... 相似文献
4.
Higher feeding diets effects on age and liveweight gain at puberty in crossbred Nelore × Hereford heifers 总被引:1,自引:1,他引:0
Júlio Otávio Jardim Barcellos Gabriel Ribas Pereira Eduardo Antunes Dias Concepta McManus Leonardo Canellas Mari Lourdes Bernardi Adriana Tarouco Ênio Rosa Prates 《Tropical animal health and production》2014,46(6):953-960
This study was conducted to determine the age and liveweight at puberty of 120 crossbred beef heifers submitted to four diets to achieve predetermined weight gains (kg/day): 0.5 (G500; n?=?32), 0.75 (G750; n?=?32), 1.0 (G1000; n?=?29), and 1.25 (G1250; n?=?27). Animals were classified depending on their level of crossing between Nelore (N) and Hereford (H): 25%N-75%H, 37.5%N-63.5%H, 43.7%N-56.7%H, 50%N-50%H, and 75%N-25%H. Reproductive evaluation was performed at the beginning and at the end of the experimental period by ultrasonography and hormone analysis. The average age and liveweight at puberty were 388.0?±?1.9 days and 331.4?±?1.3 kg, respectively. Animals from the 25%N-75%H group reached puberty earlier than heifers from other genetic groups supplemented with G1250 diet (P?<?0.05). Heifers with higher degree of Nelore (75%N-25%H) fed with G1000 diet showed estrus 42 days prior to mating, but only 57 % reached puberty at mating (P?<?0.05). Heifers with follicles of higher diameter reached puberty (P?<?0.05) earlier. Higher average daily weight gain showed a positive effect on follicular diameter and IGF-I level at puberty (P?<?0.01). Concentrations of GH were lower in heifers fed G1250 compared to G1000 diet (P?<?0.05). There was a significant interaction between nutritional level and insulin levels at puberty (P?<?0.01). We demonstrated the relationship between IGF-I and average daily gain on the onset of puberty in heifers. In conclusion, heifers submitted to the higher feeding level showed a higher follicular diameter and were younger at puberty. 相似文献
5.
Rodríguez-Cortés A Fernández-Bellón H Ramis A Ferrer L Alberola J Solano-Gallego L 《Veterinary immunology and immunopathology》2007,116(3-4):190-198
In the current retrospective study, Leishmania infantum-specific IgG, IgA and IgM levels were determined by ELISA in 106 untreated dogs with clinically-patent leishmaniasis (Sx) and in 171 clinically healthy dogs (Asx) from Spain to investigate the relationship between these Ig isotypes and clinical status. In addition, we studied if different Leishmania-specific humoral pattern exists between Asx dogs with and without cellular mediated immunity (CMI). Fifty-six dogs were assessed by means of lymphoproliferation assay (LPA), interferon production (IFN) and leishmanin skin test (LST), 71 dogs by means of both LPA and IFN and 44 only by LST. Both Sx and Asx dogs produced Leishmania-specific IgG, IgA and IgM antibodies, however the levels and proportion of positive dogs for each Ig isotype were significantly higher in Sx than in Asx ones (P<0.001). Analysis of immunological profiles determined for each cellular technique (positive and negative cellular response for each technique combined with positive or negative specific humoral response) showed that Asx dogs constituted a high heterogeneous group. No correlations were observed between CMI tests and specific IgG or IgM levels. However, a significant inverse correlation was demonstrated between specific IgA levels and LPA response (Spearman's r=-0.220; P=0.035). In general, the low correlation detected between CMI tests and isotype levels might indicate that the immune response is not strongly polarized in the majority of Asx dogs. Additionally, this study suggests that dogs developing T-cell response are probably able to avoid the dissemination of the parasite at least to mucosal surfaces and, as a consequence, to produce low or background specific IgA levels. Further studies are needed to investigate the relationship between specific IgA and parasite load, especially at mucosal site. 相似文献
6.
Serra-Majem L Ribas L Ngo J Ortega RM García A Pérez-Rodrigo C Aranceta J 《Public health nutrition》2004,7(7):931-935
OBJECTIVE: To evaluate dietary habits in Spanish children and adolescents based on a Mediterranean Diet Quality Index tool, which considers certain principles sustaining and challenging traditional healthy Mediterranean dietary patterns. DESIGN: Observational population-based cross-sectional study. A 16-item Mediterranean Diet Quality Index was included in data gathered for the EnKid study (in which two 24-hour recalls, a quantitative 169-item food-frequency questionnaire and a general questionnaire about socio-economic, demographic and lifestyle items were administered). SETTING: Spain. SUBJECTS: In total, 3850 children and youths aged 2-24 years residing in Spain. RESULTS: Of the sample, 4.2% showed very low KIDMED index results, 49.4% had intermediate values and 46.4% had high index results. Important geographical differences were seen, with subjects from the Northeast showing the most favourable outcomes (52% with elevated scores vs. 37.5% of those from the North). Lower percentages of high diet quality were observed in low socio-economic groups, compared with middle and upper income cohorts (42.8%, 47.6% and 54.9%, respectively). Large cities had more positive results and only slight variations were seen for gender and age. CONCLUSIONS: The KIDMED index, the first to evaluate the adequacy of Mediterranean dietary patterns in children and youth, confirms that this collective is undergoing important changes, which makes them a priority target for nutrition interventions. Results challenge certain commonly perceived notions tied to income level, population size and diet quality. 相似文献
7.
Isabel Dorado Li?án Emilia Gutiérrez Ingo Heinrich Laia Andreu-Hayles Elena Muntán Filipe Campelo Gerhard Helle 《European Journal of Forest Research》2012,131(4):933-944
Aging in trees implies a progressive reduction in the growth rate, related to a shortening of the growing period and changes in the photosynthetic capability and efficiency. These changes may continue during the old-growth life stages following the juvenile phase and are reflected in tree-ring properties such as growth increment, density or stable isotopes. We studied possible climate age effects in time series of several tree-ring parameters (ring width, wood density and stable carbon and oxygen isotopes) of mature individuals from two age groups of Pinus uncinata and P. nigra at two locations in Spain. The aim was to test whether age differences in trees in the old-growth life stages could lead to diverging climate responses. The results show some differences in response to climate between age groups at a monthly level, but most of these divergences are not significant for seasonal climate variables. Regardless of the age group, the main limiting climate factors constrained tree growth equally. Although our findings do not support the idea of an age-dependent response to climate that may lead to inaccurate climate reconstructions, further studies using tree-ring density and stable isotope series are urgently needed to verify the current results. 相似文献
8.
Silva Silviany Angelica Fernandes Silva Fláive Loyze Baldassarini Ribas Alessandra Ferreira de Souza Silvia Graciele Hülse dos Santos Tiago Benedito 《Journal of Crop Science and Biotechnology》2020,23(3):241-251
Journal of Crop Science and Biotechnology - Superoxide dismutases (SODs) are a group of enzymes that play essential roles in catalyzing the dismutation of superoxide radicals to protect cells from... 相似文献
9.
Charmaine D Espinosa John K Mathai Laia Blavi Yanhong Liu John K Htoo J Caroline Gonzalez-Vega Hans H Stein 《Journal of animal science》2021,99(9)
An N-balance experiment was conducted to test the hypothesis that d-Methionine (d-Met) has the same bioavailability and efficacy as l-Methionine (l-Met) when fed to weanling pigs. A Met-deficient basal diet containing 0.24% standardized ileal digestible (SID) Met was formulated. Six additional diets were formulated by adding 0.036%, 0.072%, or 0.108% d-Met or l-Met to the basal diet, and these diets, therefore, contained 77%, 87%, or 97% of the requirement for SID Met. Fifty-six barrows (10.53 ± 1.17 kg) were housed in metabolism crates and allotted to the seven diets with eight replicate pigs per diet. Feces and urine were collected quantitatively with 7-d adaptation and 5-d collection periods. Blood and tissue samples from pigs fed the basal diet and pigs fed diets containing 0.108% supplemental Met were collected on the last day. Results indicated that N retention (%) linearly increased (P < 0.01) as supplemental d-Met or l-Met increased in diets. Based on N retention (%) as a response, the linear slope-ratio regression estimated the bioavailability of d-Met relative to l-Met to be 101% (95% confidence interval: 57%–146%). The villus height and crypt depth in the jejunum were not affected by the Met level or Met source. Total antioxidant capacity or thiobarbituric acid reactive substance concentrations in plasma or tissue samples from pigs fed the control diet or diets containing 0.108% supplemental d-Met or l-Met were not different. Abundance of mRNA for some AA transporters analyzed in intestinal mucosa of pigs also did not differ. Therefore, it is concluded that d-Met and l-Met are equally bioavailable for weanling pigs. 相似文献
10.
Felicitat Todolí Laia Solano-Gallego Ana Ojeda Josefina Quintana Albert Lloret Xavier Roura Jordi Alberola Alhelí Rodríguez-Cortés 《Veterinary parasitology》2009
Recently, anti-Leishmania IgG has been detected in urine samples from Leishmania-infected dogs and its concentrations have been correlated with impairment of renal function. The presence and relationship with other anti-Leishmania Ig isotypes in urine have not yet been investigated. The current study analyzed the concentrations of anti-Leishmania IgA and IgG in sera (Ig-S) and urine (Ig-U) samples by ELISA in 64 untreated dogs with clinical leishmaniasis. All 64 serum samples tested were positive for anti-Leishmania IgG. Fifty of them (78.1%) were also positive for anti-Leishmania IgA. The results showed the presence of anti-Leishmania IgA-U in 38% of the 50 dogs that were positive for specific IgA-S. Thirty-eight of the 64 dogs positive for Leishmania-specific IgG-S (59.4%) were also positive for Leishmania-specific IgG in urine (IgG-U). The concentrations of anti-Leishmania IgA-U were significantly correlated with urine protein/creatinine (uP/C) ratio (ρ = 0.542; P < 0.001) and with serum biochemical parameters, such as γ-globulins, urea and creatinine. Goldmann–Witmer coefficient (C value) indicated that detection of specific IgA in urine samples from dogs with leishmaniasis might not only be due to impairment of filtration of the glomerular barrier but also be due to local production of this isotype, which might reflect a local immunological response to the presence of the parasite in the genitourinary tract. Anti-Leishmania IgG-U concentrations were highly correlated with uP/C ratio (ρ = 0.779; P < 0.001) and C value did not support in any case local production of this isotype. IgG isotype might be a more suitable and specific tool to evaluate renal damage due to the lower IgA-U sensitivity and correlation coefficients and evidence of IgA local production. However, dogs found positive for both Ig isotypes in urine presented significantly higher specific IgG-U concentrations and higher uP/C ratios than dogs found positive only for IgG-U, thus suggesting that the first group suffered more severe renal damage. This fact makes it necessary to evaluate the prognosis of dogs showing both anti-Leishmania IgA-U and IgG-U in future studies. 相似文献