全文获取类型
收费全文 | 2177篇 |
免费 | 164篇 |
专业分类
林业 | 214篇 |
农学 | 98篇 |
基础科学 | 17篇 |
580篇 | |
综合类 | 81篇 |
农作物 | 129篇 |
水产渔业 | 262篇 |
畜牧兽医 | 750篇 |
园艺 | 51篇 |
植物保护 | 159篇 |
出版年
2023年 | 21篇 |
2022年 | 38篇 |
2021年 | 84篇 |
2020年 | 89篇 |
2019年 | 80篇 |
2018年 | 87篇 |
2017年 | 119篇 |
2016年 | 89篇 |
2015年 | 81篇 |
2014年 | 101篇 |
2013年 | 143篇 |
2012年 | 181篇 |
2011年 | 191篇 |
2010年 | 101篇 |
2009年 | 98篇 |
2008年 | 115篇 |
2007年 | 106篇 |
2006年 | 75篇 |
2005年 | 92篇 |
2004年 | 83篇 |
2003年 | 69篇 |
2002年 | 63篇 |
2001年 | 45篇 |
2000年 | 39篇 |
1999年 | 26篇 |
1998年 | 12篇 |
1997年 | 10篇 |
1996年 | 10篇 |
1995年 | 7篇 |
1994年 | 3篇 |
1993年 | 8篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 4篇 |
1971年 | 4篇 |
1970年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有2341条查询结果,搜索用时 78 毫秒
991.
Evaluation of the sexual dimorphism in Mangalarga Marchador horses using discriminant analysis 总被引:1,自引:0,他引:1
Luís Fernando Batista Pinto Fernando Queiroz de Almeida Clia Raquel Quirino Pedro Cezar Nehme de Azevedo Grasiele Coelho Cabral Edson Mauro Santos Anderson Corassa 《Livestock Science》2008,119(1-3):161-166
This study used discriminant analysis to evaluate body measures and sexual dimorphism in Mangalarga Marchador horses. Discriminant analysis is a multivariate method that generates functions to classify animals using a prior criterion. In this study a prior criterion is male or female. The study analyzed 25 linear and 11 angular measures obtained from 25 stallions and 56 mares registered with the Mangalarga Marchador Brazilian Breeders Association. Knee girth, cannon girth, chest width, chest girth, back-loin length, hip width, distance from elbow to knee, hind limb hoof length, head width, shoulder length, and body length were found to be linear measures that provided evidence of sexual dimorphism. Angular measures with evidence of sexual dimorphism were shoulder–humerus, metacarpal–phalanx, coxae–femur, and femur–tibial angles. Stallions were larger than mares for almost all linear measures, except for back-loin length, hip width, and distance from elbow to knee. Shoulder–humerus and coxal–femur angles were larger in mares, while metacarpal–phalanx and femur–tibial angles were larger in stallions. Using linear measures, two mares were classified as stallions and three stallions were classified as mares. For angular measures, two other mares were classified as stallions and three other stallions were classified as mares. The discriminant functions can be useful for the selection of horses and to avoid registration of animals not meeting the phenotypic standards of the breed association. 相似文献
992.
Francisco de Assis Alves Mourão Filho Rafael Pio Beatriz Madalena Januzzi Mendes Fernando Alves de Azevedo Evandro Henrique Schinor Fábio Albuquerque Entelmann André Siqueira Rodrigues Alves Tatiana Eugenia Cantuarias-Avilés 《Scientia Horticulturae》2008
Somatic hybridization is a biotechnology tool that can be used in citrus breeding programs to produce somatic hybrids with the complete genetic combination of both parents. The goal of this work was to test the reaction of citrus somatic hybrids that may be useful as rootstocks to trunk and root infections caused by Phytophthora nicotianae van Breda de Haan (P. parasitica Dastur) and to citrus tristeza virus (CTV). The somatic hybrids evaluated were ‘Caipira’ sweet orange (Citrus sinensis L. Osbeck) + ‘Rangpur’ lime (C. limonia Osbeck), ‘Caipira’ sweet orange + ‘Cleopatra’ mandarin (C. reshni hort. ex Tanaka), ‘Caipira’ sweet orange + ‘Volkamer’ lemon (C. volkameriana V. Ten. & Pasq.), ‘Caipira’ sweet orange + rough lemon (C. jambhiri Lush.), ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, ‘Cleopatra’ mandarin + sour orange (C. aurantium L.), ‘Rangpur’ lime + ‘Sunki’ mandarin (C. sunki (Hayata) hort. ex Tanaka), ‘Ruby Blood’ sweet orange (C. sinensis L. Osbeck) + ‘Volkamer’ lemon, ‘Rohde Red’ sweet orange (C. sinensis L. Osbeck) + ‘Volkamer’ lemon, and ‘Valencia’ sweet orange + Fortunella obovata hort. ex Tanaka. For P. nicotianae trunk and root infection assays, plants of the somatic hybrids, obtained from 9-month semi-hardwood cuttings, were evaluated and compared with diploid citrus rootstock cultivars after mycelia inoculation in the trunk or spore infestation in the substrate, respectively. ‘Cleopatra’ mandarin + sour orange, ‘Rangpur’ lime + ‘Sunki’ mandarin, ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, ‘Ruby Blood’ sweet orange + ‘Volkamer’ lemon, ‘Rohde Red’ sweet orange + ‘Volkamer’ lemon, and ‘Caipira’ sweet orange + ‘Volkamer’ lemon had less trunk rot occurrence, whereas the somatic hybrids ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, ‘Cleopatra’ mandarin + sour orange, ‘Caipira’ sweet orange + ‘Volkamer’ lemon, and ‘Caipira’ sweet orange + ‘Rangpur’ lime were tolerant to root rot. For CTV assays, plants of the somatic hybrids along with tolerant and intolerant rootstocks were budded with a mild strain CTV-infected or healthy ‘Valencia’ sweet orange budwood. Differences in average scion shoot length indicated that the hybrids ‘Cleopatra’ mandarin + sour orange and ‘Valencia’ sweet orange + Fortunella obovata were intolerant to CTV. 相似文献
993.
Molina JM Ruiz A Hernández B González JF Martín S Hernández YI 《Australian veterinary journal》2008,86(11):444-445
The effect of eprinomectin on goats experimentally infected with the nematode Haemonchus contortus was investigated. Faecal analysis showed that a single dose of eprinomectin 'pour-on' delayed the onset of shedding of eggs for 10 to 17 days. 相似文献
994.
The objective of the study was to estimate genetic parameters for length of productive life (LPL), and determine its genetic correlation with age at first farrowing (AFF), number of piglets weaned at first farrowing (NW), and first wean-to-insemination interval (W2I) in the Finnish Landrace swine population. Data from the Finnish national litter recording scheme were utilized to estimate the genetics of LPL, and genetic associations between LPL, AFF, NW, and W2I. Data from the Finnish Landrace sow records were utilized from farms that farrowed more than 20 gilts annually from 2000 through 2005. The data set included information from 11,222 sows, all of which had AFF and NW information available. The sows producing the records evaluated were daughters of 1,267 sires, and there were 3,684 animals in the pedigree when all of the sires were traced back to founder animals. All data were obtained from FABA Breeding (Vantaa, Finland). Multivariate Bayesian analysis of Gaussian, right censored Gaussian, and categorical traits was utilized to estimate (co)variance parameters of LPL, AFF, NW, and W2I of the sow. From these traits, AFF and NW were treated as Gaussian, LPL as right-censored Gaussian, and W2I as categorical traits. Estimated posterior means of heritabilities were 0.22, 0.16, 0.09, and 0.08 for LPL, AFF, NW, and W2I, respectively. A relatively large proportion of variance due to farm-year interaction was observed (posterior means of f(2) ranged between 0.03 and 0.26). The LPL was moderately genetically correlated with NW and AFF (posterior means were -0.20 and 0.36, respectively), whereas no clear association was found between W2I and LPL. Favorable genetic correlations between AFF and W2I and between NW and W2I were also observed. Additionally, an unfavorable genetic correlation between AFF and NW was observed in the present data set. Because LPL is genetically associated with other economically important prolificacy traits, it should be included in a multiple trait swine breeding value estimation system. 相似文献
995.
de Lucas JJ San Andrés MI González F Froyman R Rodríguez C 《Veterinary research communications》2008,32(4):275-279
This study compared pharmacokinetic profiles in cattle dosed subcutaneously with two different formulations of enrofloxacin
(5% and 10%) at a dose of 5 mg/kg. Plasma concentrations of enrofloxacin and its active metabolite, ciprofloxacin, were determined
by a HPLC/u.v. method. The pharmacokinetic parameters of enrofloxacin and its metabolite were similar in both injectable formulations.
Enrofloxacin peak plasma concentration (5%: 0.73 ± 0.32; 10%: 0.60 ± 0.14 μg/mL) was reached at 1.21 ± 0.52 and 1.38 ± 0.52 h
to 5 and 10%, respectively. The terminal half-live and area under curve were 2.34 ± 0.46 and 2.59 ± 0.46 h, and 3.09 ± 0.81
and 2.93 ± 0.58 μg·h/mL, to 5 and 10%, respectively. The AUC/MIC90 and Cmax/MIC90 ratios for both formulations exceed the proposed threshold values for optimized efficacy and minimized resistance development
whilst treating infections or septicaemia caused by P. multocida and E. coli. 相似文献
996.
Martínez-Barbabosa I Quiroz MG González LA Cárdenas EM Edubiel AA Juárez JL Gaona E 《Veterinary parasitology》2008,153(3-4):270-276
Toxocara canis is a common intestinal helminth found in dogs. In humans, it is a cause of Visceral Larva Migrans (VLM), a zoonosis rarely studied in Mexico. The aim of this study is to examine, by means of the indirect haemaglutination test (IHAT), the prevalence of antibodies of T. canis in the serum of stray dogs in Mexico City. METHODS AND MATERIALS: 141 stray dog serum samples from three different districts of the city were analyzed: Iztacalco (49), Iztapalapa (49) and Coyoacan (43). In each location three study groups were formed. Group I with 35 dogs (less than a year old), Group II with 91 dogs (ages 1相似文献
997.
Ruiz A Foronda P González JF Guedes A Abreu-Acosta N Molina JM Valladares B 《Veterinary parasitology》2008,154(1-2):137-141
Giardia duodenalis (syn. Giardia lamblia, Giardia intestinalis) is a wide-spread intestinal protozoa of both humans and animals. Although giardiosis in goat is commonly asymptomatic, young kids may bear an enteric disease associated with persistent diarrhoea and delayed weight gain. In the present study we have analysed the occurrence of Giardia in 315 young goat kids (2–6 months old) from Gran Canaria Island (Spain) through visualization of faecal cysts. The identification of genotypes of G. duodenalis among the farms was attained by nested PCR of the triophosphate isomerase (TPI) and single PCR of β-giardin genes and subsequent sequencing. Positive samples were found in 42.2% of the animals and 95.5% of the farms. Goat faecal specimens were positive for only livestock-associated G. duodenalis assemblage E genotype for both TPI and β-giardin genes. The genetic analysis of these two loci revealed the presence of different haplotypes among the farms included in the survey and high homology with homologous genes from cattle and sheep. Altogether, the data presented here provide additional information to the prevalence and genetic characterization of Giardia isolates. The absence of assemblages A and B in this study suggests that zoonotic transmission of Giardia from goats could be of low epidemiological significance, although these findings should be validated in studies including other geographical areas, age groups and larger number of samples. 相似文献
998.
999.
1000.
Gladys González González Rosa Ma. Salinas Hernández Andrea Marcela Piagentini Fidel Ulín Montejo Edith Miranda Cruz María Élida Pirovani 《International Journal of Fruit Science》2016,16(2):159-170
The aim of this work was to develop kinetic models to describe the sensory changes of minimally processed rambutan. Quality was assessed by a trained panel. The attributes that most decreased were freshness, aroma, and appearance (17–38%), and the defects that were more increased were off-odors and off-flavors (28–67%). Although whole fruit is sensitive to chilling injury, minimally processed rambutan is preserved better at 4.6 °C. Color, sweetness, and off-odor changes were adjusted to first-order kinetic and the other characteristics to zero order. Sourness, aroma, and color have higher activation energies (235–297.4 KJ mol–1), and these characteristics would change faster if failure in the cold chain occurs. 相似文献